review article streptozotocin-induced diabetes models:...

Review ArticleStreptozotocin-Induced Diabetes Models PathophysiologicalMechanisms and Fetal Outcomes

D C Damasceno12 A O Netto1 I L Iessi1 F Q Gallego1 S B Corvino1 B Dallaqua1

Y K Sinzato1 A Bueno1 I M P Calderon1 and M V C Rudge1

1 Laboratory of Experimental Research on Gynecology and Obstetrics Graduate Program in Gynecology Obstetrics and MastologyBotucatu Medical School UNESP-Universidade Estadual Paulista Distrito de Rubiao Junior SN 18618-970 Botucatu SP Brazil

2 Department of Gynecology and Obstetrics Botucatu Medical School UNESP-Univsidade Estadual PaulistaDistrito de Rubiao Junior SN 18618-970 Botucatu SP Brazil

Correspondence should be addressed to D C Damasceno damascenofmbgmailcom

Received 14 March 2014 Revised 30 April 2014 Accepted 14 May 2014 Published 27 May 2014

Academic Editor Luis Sobrevia

Copyright copy 2014 D C Damasceno et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

Glucose homeostasis is controlled by endocrine pancreatic cells and any pancreatic disturbance can result in diabetes Because8 to 12 of diabetic pregnant women present with malformed fetuses there is great interest in understanding the etiologypathophysiological mechanisms and treatment of gestational diabetes Hyperglycemia enhances the production of reactive oxygenspecies leading to oxidative stress which is involved in diabetic teratogenesis It has also been suggested thatmaternal diabetes altersembryonic gene expression which might cause malformations Due to ethical issues involving human studies that sometimes haveinvasive aspects and the multiplicity of uncontrolled variables that can alter the uterine environment during clinical studies it isnecessary to use animal models to better understand diabetic pathophysiology This review aimed to gather information aboutpathophysiological mechanisms and fetal outcomes in streptozotocin-induced diabetic rats To understand the pathophysiologicalmechanisms and factors involved in diabetes the use of pancreatic regeneration studies is increasing in an attempt to understandthe behavior of pancreatic beta cells In addition these studies suggest a new preventive concept as a treatment basis for diabetesintroducing therapeutic efforts to minimize or prevent diabetes-induced oxidative stress DNA damage and teratogenesis

1 Introduction

Diabetes mellitus (DM) is a chronic disease characterized byhyperglycemia resulting in insulin resistance andor insulinsecondary deficiency caused by the failure of beta- (120573-)pancreatic cells Diabetes can be classified into four clinicalcategories type 1 diabetes (due to autoimmune destructionof the 120573 cells usually leading to absolute insulin deficiency)type 2 diabetes (due to a progressive insulin secretory defectin the background of insulin resistance) gestational Diabetesmellitus (GDM) (diabetes diagnosed during pregnancy thatis not clearly overt diabetes) and other specific types ofdiabetes due to other causes for example genetic defects in120573 cell function or insulin action drug- or chemical-inducedalterations (such as in the treatment of HIVAIDS or afterorgan transplantation) and any diseases of the exocrine

pancreas characterized by a process that diffusely injures thepancreas can cause diabetes Diabetes is usually diagnosedbased on plasma glucose criteria either the fasting plasmaglucose (FPG) or the 2 h plasma glucose (2 h PG) value aftera 75 g oral glucose tolerance test (OGTT) Besides recentlyan International Expert Committee added theA1C (thresholdge 65) as a third option to diagnose diabetes In type 1diabetes patients often present acute symptoms of diabetesand markedly increased glucose levels and in some casesketoacidosis Type 2 diabetes is frequently not diagnosed untilcomplications appear ADA for the first time recommendedthat all pregnant women not known to have prior diabetesundergo a 75 gOGTT at 24ndash28weeks of gestation based on anInternational Association of Diabetes and Pregnancy StudyGroups (IADPSG) consensus meeting In US approximatelyone-fourth of the populationmay have undiagnosed diabetes

Hindawi Publishing CorporationBioMed Research InternationalVolume 2014 Article ID 819065 11 pageshttpdxdoiorg1011552014819065

2 BioMed Research International

Acquired processes include pancreatitis trauma infectionpancreatectomy and pancreatic carcinoma (such as cysticfibrosis) However for the clinician and patient it is lessimportant to label the particular type of diabetes than it isto understand the pathogenesis of hyperglycemia and to treatit effectively [1]

Research in health has been improving the quality ofmedical care influencing health policies and ensuring patientsafety Translational research is an important tool that allowsresearchers in clinical practices to establish knowledge andimplement the results [2] Translational research covers twoareas One is the process of applying discoveries generatedduring research in the laboratory and in preclinical studies tothe development of trials and studies in humans The secondarea of translation concerns research aimed at enhancingthe adoption of best practices in the community The cost-effectiveness of prevention and treatment strategies is alsoan important part of translational science [3] According tothis definition translational research is part of a unidirec-tional continuum in which research findings move from theresearcherrsquos bench to the patientrsquos bedside and the commu-nity In the continuum the first stage of translational research(T1) transfers knowledge from basic research to clinicalresearch while the second stage (T2) transfers findings fromclinical studies or clinical trials to practice settings andcommunities where the findings improve health [4] Dueto ethical issues involving human studies that can requireinvasive aspects and themultiplicity of uncontrolled variablesthat can alter the uterine environment during clinical studies[5] it is necessary to use animal models to better understanddiabetic pathophysiology [6] Thus this review aimed togather information about pathophysiological mechanismsand fetal outcomes in streptozotocin-induced diabetic rats

2 Pancreatic Islets Structure and FunctionThe pancreas is a complex organ that consists of twofunctionally and morphologically distinct cell populationsderived from the endoderm The exocrine pancreas consistsof acinar cells that secret digestive enzymes such as amylaseslipases proteases and nucleases which are emptied into thepancreatic duct through an elaborately branched networkof tubules composed of epithelial cells Acinar cells alsoproduce bicarbonate ions and electrolytes which togetherwith exocrine enzymes are transported through the mainduct into the duodenum where they contribute to foodprocessing [7 8]

Groups of endocrine cells called pancreatic islets repre-sent the endocrine portion which composes only approx-imately 2 of the pancreas Each islet is composed ofat least five types of cells including insulin-producing 120573cells (65ndash80) [9] glucagon-releasing 120572 cells (15ndash20)[10] somatostatin-producing 120575 cells (3ndash10) [11] pancre-atic polypeptide-containing PP cells (1) [12] and ghrelin-containing 120576 cells [13] All of these hormones are involvedin the regulation of nutrient metabolism and glucose home-ostasis [14] The cytoarchitecture of rodent and human isletspresents notable differences [15 16] In islets from mice andother rodents the 120573 cells are predominately located in the

central core with 120572 and 120575 cells localized in the peripheryforming amantle [17ndash21] In human andmonkey islets120572 cellsare not localized in the periphery but rather are dispersedthroughout the islet [15 16 19 21 22]

There are several lines of evidence that pancreatic isletscannot be considered aggregates of cells It was well estab-lished more than 20 years ago that the integrated secretoryresponses of isolated islets are greater than those of dispersedislet cells suggesting that cell-to-cell interactions are nec-essary for the normal secretory function of the endocrinepancreas [23ndash27]

However there are no reports regarding the effectendocrine hormones in the diabetic environment Severalstudies have emphasized the importance of interactionsamong the different cells [28 29] and between cells of thesame type [29 30] in metabolic control In normal isletsthe insulin-producing cells are under the influence of otherhormone-secreting islet cells Glucagon is known to enhanceboth insulin and somatostatin secretion while somatostatinexerts an inhibitory effect on insulin and glucagon secretion[31 32] Communication among these hormones is importantto maintain physiological balance and any disorder in thissystem would result in excessive blood glucose levels forexample damaging the organism

Hyperglycemia during pregnancy impairs the intrauter-ine environment affecting normal fetal development andresulting in long-term effects on the function and structureof fetal pancreatic islets [33 34] This status increases theoffspringrsquos risk of obesityadiposity glucose intolerance andtype 2 diabetes later in life [1 35ndash37] Animal studies haveshown that the offspring of diabetic rats can be insulin resis-tant [38 39] and diabetic [39 40] Studies support the conceptthat developing organs have critical periods of intense struc-tural and functional reorganization In the case of the pan-creas this circumstance may render it vulnerable to environ-mental stimuli [41 42] which may lead to consequences forthe next generation [43] and future studies should considerthe hormone interactions involved for this glucose control

The literature shows that the administration of pancreatichormones analogs (insulin glucagon and somatostatin) in invitro studies is important to investigate the mechanisms ofhormonal synthesis and secretion in an isolatedmanner [44ndash46] In addition insulin is the most studied hormone in thematernal and fetal organism in an attempt to understand therepercussions of hyperglycemia [47ndash54] In our laboratorywe hypothesized that glucoregulatory hormones such asglucagon and somatostatin in addition to insulin are relevantfor embryo-fetal development and diabetes-derived alter-ations We performed an experimental study in rats to eval-uate the importance of the endocrine pancreatic hormonaltriad in maternal fetal and neonatal organisms exposed toa hyperglycemic intrauterine environment According to ourresults somatostatin levels were altered in all developmentalpoints studied showing that pancreatic alteration inmaternaland fetal organisms persisted in the neonatal period Theseresults suggest that somatostatin might be a predictor ofadverse effects in adulthood In fact our data show the impor-tance of studying hormonal interactions in the endocrinepancreas to understand the pathophysiological mechanisms

BioMed Research International 3

related to glycemic control in maternal and fetal organisms[55]

3 Pathophysiological Mechanisms ofDiabetic Disease

The chronic hyperglycemia of diabetes is associated withlong-term damage dysfunction and failure of differentorgans especially the eyes kidneys nerves heart and bloodvessels [1] Type 1 Diabetes mellitus results from the cell-mediated autoimmune destruction of the 120573-cells of thepancreas Markers of the immune destruction of the 120573-cellinclude islet cell autoantibodies autoantibodies to insulinautoantibodies to GAD (GAD65) and autoantibodies tothe tyrosine phosphatases IA-2 and IA-2b [1] Autoimmunedestruction of 120573-cells has multiple genetic predispositionsand is also related to environmental factors that are stillpoorly defined Individuals who present Type 2 Diabetesmellitus have insulin resistance and usually develop relative(rather than absolute) insulin deficiency Although the spe-cific etiologies are not known autoimmune destruction of 120573-cells does not occur Most patients with this form of diabetesare obese and obesity itself causes some degree of insulinresistance [1] Elevations in plasma glucose and free fattyacids are thought to increase reactive oxygen species (ROS)levels [56 57] which in turn activate inflammation signalingpathways such as mitogen-activated protein kinases [58] andnuclear factor-kB [59] The activation of these inflammationcascades is thought to cause insulin resistance [60]

Gestational Diabetes mellitus (GDM) has been definedas any degree of glucose intolerance with onset or firstrecognition during pregnancy (ADA) Glucose intolerancewas first introduced in 1979 to replace ldquoborderlinerdquo diabetesand other categories of hyperglycemia that did not appearto carry a risk of microvascular complications [61 62] Itwas only in the most recent reports that the category ofnondiabetic fasting hyperglycemia was defined and given thename impaired fasting glycemia (IFG) [63 64]This indicatesglucose concentrations that are clearly above normal but fallshort of the diagnostic value for diabetes [65]

4 Diabetes and PregnancyExperimental Models

Experimentally induced diabetes through the administrationof 120573-cytotoxic drugs such as streptozotocin (STZ) is wellcharacterized [66] Streptozotocin is an antimicrobial agentandhas also beenused as a chemotherapeutic alkylating agent[67] ldquoStreptozotocin diabetesrdquo [68] is caused by the specificnecrosis of the pancreatic 120573-cells and this agent is the firstchoice for diabetes induction in animals [69 70] Dependingon the animal strain dose route of drug administration andthe life period in which STZ is administered in rats severediabetes (blood glucose superior to 200300mgdL) [71ndash77]or mild diabetes (glycemia between 120 and 200300mgdL)are generated [68 78ndash81] For severe diabetes induction STZis administered at 40ndash50mgkg body weight intravenouslyor intraperitoneally during adulthood After approximately

three days these animals present blood glucose levels greaterthan 300mgdL [79 82ndash86] In our laboratory to inducemilddiabetes which is characterized by low glycemic intensity therats received a STZ injection (dose of 100mgkg body weight)subcutaneously at birth Approximately three days afterSTZ administration these animals developed hyperglycemia(gt300mgdL) and presented low blood glucose levels (120ndash200mgdL) at adulthood [83 85ndash93] This fact might beexplained by the high regenerative capacity of 120573-cell duringthe neonatal period [94 95]

The literature has shown that several organs are able toundergo catch up growth when necessary [96] In case ofsevere cell loss or physiological conditions the pancreatic 120573-cells of rodents can regenerate in the early life period [97]Cell regeneration can occur through different mechanismssuch as neogenesis proliferation [98 99] and transdiffer-entiation [100] Scaglia et al [101] showed that during theneonatal period the pancreas suffers physiological changesevents that can also be identified in other organs for exampleliver kidneys and central nervous system [102ndash105] Thispancreatic remodeling is due to increased replication andapoptosis rates of 120573-cells between days 13 and 17 These datashow that in physiological conditions the organism has adynamic 120573-cell mass maintaining glucose homeostasis [95106]

Because 120573-cells are able to regenerate in physiologicalconditions the next step was to develop an experimentalmodel to induce islet injury to study themechanisms involvedin cell regeneration process Bonner-Weir et al [97] publishedsome of the first data about pancreatic islet regenerationadministrating STZ on the second postnatal day Two daysafter the induction of diabetes the animals presented highblood glucose levels (gt300mgdL) and reduced 120573-cell num-bers compared to the control group At postnatal day 10the animals became euglycemic and partial regenerationof pancreatic 120573-cells was evidenced The authors suggestedcellular proliferation as the mechanism of cell regenerationAfter STZ administration cells that were not affected by STZ-induced necrosis showed increased mitotic characteristicsBonner-Weir et al [107] showed increasedmitosis apoptosisand hypertrophic cells and suggested that hypertrophymightbe related to increased 120573-cell mass given that cell death is amechanism of regulation related to the rate of mitosis whichcould maintain an appropriate number of islet cells There-fore according to these authors the increased 120573-cell masscould be due to replication individual cell hypertrophy orislet neogenesis by ductal cell differentiation [108] Regardingthe regeneration mechanisms of 120573-cells some authors alsosuggest cell transdifferentiation from non-120573-cells to insulin-producing cells In contrast Scaglia et al [101] concluded thatonce cells do not present hormonal co-expression there isno transdifferentiation suggesting that non-120573-cells are notdifferentiating into 120573-cells

In contrast other authors defend the idea that 120572-cellsare able to differentiate into 120573-cells by direct conversion oftranscription factors [100 109ndash112] Some of the essentialtranscription factors involved in pancreatic regeneration havebeen investigated such as neurogenin 3 (Ngn3) paireddomain homeobox gene 4 (Pax4) and homeobox-containing


gene (Arx) Ngn3 is expressed by precursors of the endocrinepancreas Pax4 has selective expression throughout the pan-creatic islet during its development and is then restricted to120573-cells [113 114] and Arx is expressed by pancreatic 120572-cells[100]

Liang et al [95] found that 120573-cells were damaged fourdays after neonatal STZ induction At day 8 these authorsverified that there was 120573-cell recuperation but 20 daysafter STZ injection the 120573-cell mass was still reduced eventhough blood glucose levels reverted to normal This studyfocused on transcription factors and the authors used doubleimmunofluorescence to stain Ngn3 and insulin or glucagonBy analyzing the coexpression of Ngn3 and glucagon theyobserved abundant expression of Ngn3 in the 120572-cells of STZ-treated rats 8 and 12 days after STZ injection However inthe control rats few 120572-cells expressed Ngn3 The results ofthe diabetic group indicated that 120572-cells dedifferentiated intoprecursor cells and may be candidates for 120573-cell formationThe coexpression of Pax4 and insulin or glucagon was alsostudied and indicated a relationship between insulin andPax4 in both the control and STZ groups However thecoexpression of Pax4 and glucagon was verified 12 and 20days after STZ administration Ngn3 expression is necessaryfor transdifferentiation from 120572- to 120573-cells In addition Pax4is an important transcription factor that specifies the 120573-celllineageThe same authors observedPax4 expression in120572-cellsof both control and STZ-treated rats but this coexpressionincreased in the 120572-cells at day 20 These results demon-strate that 120572-cells are sources of 120573-cell regeneration andcan undergo transdifferentiation Another study using STZshowed that Arx inactivation in 120572-cells results in pancreaticislet hypertrophy and increased number of cells that arephenotypically 120573-cells The authors suggest that when 120572-cellsare subjected to Arx inactivation they undergo transdiffer-entiation to 120573-cells These results show that strategies aimingat inhibiting the expression of Arx may offer new avenues fordiabetes treatment [115]

Therefore the literature includes several mechanisms toexplain 120573-cell regeneration and most studies suggest thatthe proliferation of the remaining 120573-cells is the primarysource of regeneration Nevertheless current studies havedemonstrated the direct participation of 120572-cells in 120573-cellregeneration Thus we conclude that the regeneration ofpancreatic 120573-cells may be due to different mechanismsbut further studies are needed to precisely elucidate eachmechanism and its contribution to the regeneration as awhole

5 Diabetes-Induced TeratogenesisDiabetes has been recognized as a disease that increases therisk of birth defects in offspring by 3 to 5 times [116] A sig-nificant improvement has been observed in the evolution ofthe diabetic pregnancy after the discovery of insulin reducingthe incidence of ketoacidosis spontaneous abortions still-births and congenital malformations [117] A total of 25 ofoffspring have been reported presenting these complicationsand early detection and subsequent strictmetabolic control ofpregnantwomenwith diabetes should decrease the frequency

and severity of some of these complications in offspring[118] Studies have shown that spontaneous abortions canresult from the malformation of structures required for fetalviability such as the cardiovascular system or the placentabut could also be attributable to maternal effects such asendocrinopathies or vascular complications affecting uterineperfusion [119]

The following are the two principal advances that haveimproved the offspring survival rate during diabetic preg-nancy (1) a good maternal glycemic control to reducethe morbidity and mortality of both the mother andfetusneonate [120] (2) availability of surfactant to reduceperinatalmortality from respiratory distress syndrome (RDS)[121] Uncontrolled diabetic status throughout the pregnancyhas been associated with a spectrum of disorders involvingneural tube defects (NTDs) including spina bifida anen-cephaly encephalocele holoprosencephaly and cardiovascu-lar [122ndash124] kidney and skeletal system defects in additionto growth delay and miscarriage [116] In fact any organcan be affected and 8 to 12 of diabetic pregnant womenpresented malformed fetuses [125]

Experimental studies have also been performed to under-stand diabetic teratogenesis Damasceno et al [126] and Vol-pato et al [75] administered STZ (40mgkg) to adult virginfemale Wistar rats before mating During pregnancy theserats presented hyperglycemic levels higher than 200mgdLAt term the fetuses from diabetic dams presented skeletal(nonossified sternebrae and cleft palate) and visceral malfor-mations (microphthalmia and hydronephrosis) Gareskog etal [127] using a similar diabetes model recovered embryosfrom diabetic rats at day 10 or 11 of pregnancyThese embryoswere cultured within their intact visceral yolk sac for 24or 48 h and presented decreased Bcl-2 levels and increasedBax levels and increased activation of caspase 3 Thusexposure to diabetes during organogenesis increased cellularapoptosis and embryonic dysmorphogenesis However someskeletal defects that can occur in human diabetic pregnancyparticularly caudal regression syndrome are rarely observedin animal models making it difficult to study their molecularetiology [119]

Several studies have tried to identify biochemical dis-turbances associated with malformations in animal modelsof diabetic pregnancy Teratogenic processes in embryonictissues include alterations of metabolic and signaling systems[118] such as metabolism of inositol [128] the polyol pathway[129] arachidonic acidprostaglandins [130 131] and reactiveoxygen species (ROS) [132] In the polyol pathway thealdose reductase enzyme is responsible for catalyzing excessglucose into sorbitol Sorbitol accumulation has been demon-strated to negatively affect cell function in glucose-permeabletissues However aldose reductase inhibitors (ARIs) candiminish some diabetes-related changes in affected tissueswithout modifying the hyperglycemia It has been proposedthat polyol pathway overactivity is responsible for diabeticnephropathy neuropathy and retinopathy due to the deple-tion of myoinositol and this could be applied to diabeticcongenital malformations [118]

Another theory centers on linoleic acid It is the pre-cursor of arachidonic acid an essential fatty acid required


throughout gestation [133] The literature shows that arachi-donic acid release from plasma membranes by phospho-lipase A2 is lower in diabetic rodents The formation ofthe palate the neural tube the heart and external geni-talia involve the folding and fusion of opposing layers andrequire phosphatidylinositol turnover and arachidonic acidsignaling [131] Several studies have identified PGE2 as aprostaglandin (PG) derived from arachidonic acid involvedin the prevention of malformations in experimental diabeticmodels [134 135] Supporting this idea one study showedthat the concentration of PGE2 decreased during neurula-tion in embryos from a diabetic mouse [136] In vitro aswell as in vivo results demonstrated that a high glucoseconcentration causes decreased cyclooxygenase (enzyme cat-alyzing the synthesis of PGE2 from arachidonic acid) geneexpression [137] suggesting that diabetes causes decreasedprostaglandin biosynthesis and that the inhibition of thearachidonic cascade may be a cause of diabetic embryopathy[138]

Another hypothesis is that increased glucose metabolismenhances the production of ROS causing oxidative stress[139] In the embryo the energy metabolism is characterizedby a high rate of glycolysis and lactic acid production(anaerobic glycolysis) with minimal activity of the Krebscycle-electron transport system [138] In accordance withthe low activity of the mitochondrial oxidative pathwayscavenging enzymes such as superoxide dismutase (SOD)catalase and glutathione peroxidase (GPx) seem to be imma-ture during the period of early organogenesis [140] A studyperformed on cultured rat embryos in high glucose (25 and50mM glucose) showed increased activity of the free radicalscavenging enzyme superoxide dismutase (SOD) providingevidence of enhanced ROS production in a hyperglycemicenvironment [141] Kinalski et al [142] verified an increasein malondialdehyde (MDA) levels and reduced glutathione(GSH) and decreased activity of cytoplasmic CuZn super-oxide dismutase (CuZn SOD) in the infants of motherswith pregestational and gestational diabetesThese data showincreased oxidative stress and lipid peroxidation in thesefetuses which serve as indicators of fetal distress caused bymaternal hyperglycemia [143]

Wentzel and Eriksson [144] evaluated embryoneural crestcells recovered from inbred Sprague-Dawley rat exposed to55 or 30mmolL glucose for 48 hr on gestational day 10 Cellsexposed to 30mmol glucoseL presented decreased mRNAlevels of catalase CuZn SOD manganese superoxide dis-mutase and extracellular superoxide dismutase This alteredgene expression induced by glucose may be the etiology ofmalformations in diabetic pregnancy

6 Diabetes-Induced Oxidative Stress andDNA Damage

In addition to reactive oxygen and nitrogen species theproducts of free radicals which are dependent on fattyacid oxidation can induce chromosome breaks [145 146]Therefore these products can interact with the embryochromatin resulting in congenital malformations [147] Free

radicals can also react with DNA bases impairing theirstructure [148 149] andpotentially leading tomutations [148ndash150] DNA oxidation is the most common type of damage[151] although the methods used to assess this damageare still controversial One marker used to study oxidativeDNA damage [152 153] is 8-OHdG or 8-oxo-78-dihydro-2-deoxyguanosine (8-oxodGuo or 8-oxoGua) It is a productof the deoxyguanosine nucleoside oxidation that is directlyexcreted in urine Qiu et al [154] demonstrated that the 8-OHdG urine concentrationmight be related to increased riskfor gestational diabetes mellitus

To evaluate DNA damage levels the comet assay presentsadvantages compared to other methods to detect genotoxicsubstances This test is not useful for detecting mutations butcan detect genomic lesions which can result in mutationIn contrast to mutations the genomic lesions detected bythe comet assay can be repaired The comet assay is fastand sensitive moreover it can detect oxidized DNA basesusing endonucleases such as endonuclease III (Endo III) andformamidopyrimidine DNA glycosidase (Fpg) Use of Fpgand Endo III allows the identification of both oxidized purineand pyrimidine bases respectively [155 156]

Although streptozotocin is an alkylating agent it is alsouseful in genotoxicity studies Some authors have suggestedthat STZ can irreversibly damage 120573-cell DNA To investigatethis hypothesis Mossman et al [157] performed an in vitrostudy showing that STZ induces single-strand DNA breaksin rodent cells (RINr 38) and these lesions are repaired 24hours after STZ exposition Studying the same cell lineagePettepher et al [158] demonstrated that STZ also inducesalkali-labile site breaks in mitochondrial DNA and eventhough the formation of this lesion is dose-dependent it canbe repaired as well After 8 hours of STZ exposition 55of the mitochondrial DNA lesions were repaired rising to70 in 24 hours These data confirm that STZ by itself is notresponsible for the high levels of DNA damage

In regard to experimental studies with mild and severediabetes Lima et al [86] evaluated oxidative damage inthe lymphocytes of pregnant diabetic rats and whole bloodsamples of their offspring by the comet assay using repairenzymes (Endo III and Fpg)These authors found that mildlydiabetic rats and their offspring presentedmore sensitive sitesto Fpg reflecting damage related to hyperglycemia Tats withsevere diabetes and their offspring showed oxidative DNAdamage detected by Fpg as well as by Endo III typical generaldiabetes outcomesThe enzymatic indication ofDNAdamagesuggests that the repercussions of maternal diabetes areassociated with oxidative lesions in maternal and fetal DNADamasceno et al [159] demonstrated that severely diabeticrats presented higher DNA damage levels at term pregnancycompared to control rats In addition their offspring alsoshowed higher DNA damage levels and increased rate ofcongenital malformations at term confirming the interactionbetween hyperglycemia-induced genotoxicity and teratoge-nesis These studies show the relationship among diabetesoxidative stress and oxidative DNA damage

Although many studies have been performed to under-stand the congenital malformations induced by diabetesadditional research is necessary to identify new markers


involved in the regulation of embryogenesis and occurrenceof congenital malformations It is necessary to comprehendDNA damage trigger factors in diabetes to reduce the impair-ment of gene expression avoid fetal congenitalmalformationand contribute to the normal development of organs duringorganogenesis

7 Conclusion

Pancreatic islet loss and reduction of insulin-producing betacell mass are relevant aspects to diabetic pathogenesis It isimportant to study the regeneration of pancreatic beta cellsnot only to understand the mechanisms and factors involvedin this process but also to provide new preventive concepts asa basis for the treatment of diabetes Thus these therapeuticeffortsmightminimize or prevent diabetes-induced oxidativestress DNA damage and teratogenesis

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgment

The authors are grateful to FAPESP (Fundacao de Amparo aPesquisa do Estado de Sao Paulo Brazil) for financial supportof the projects developed in their laboratory

References

[1] American Diabetes Association (ADA) ldquoStandards of medicalcare in diabetesmdash2014rdquoDiabetes Care vol 37 supplement 1 ppS14ndashS80 2014

[2] S Bakken and D A Jones ldquoContributions to translationalresearch for quality health outcomesrdquoNursing Research vol 55no 2 pp S1ndashS2 2006

[3] National Institutes of Health ldquoDefinitions under Subsection 1(Research Objectives) Section I (Funding OpportunityDescription) Part II (Full Text of Announcement) of RFA-RM-07-007rdquo Institutional Clinical and Translational ScienceAward (U54) 2007 httpgrantsnihgovgrantsguiderfa-filesRFA-RM-07-007html

[4] D M Rubio E E Schoenbaum L S Lee et al ldquoDefiningtranslational research implications for trainingrdquo AcademicMedicine vol 85 no 3 pp 470ndash475 2010

[5] I Lopez-Soldado and E Herrera ldquoDifferent diabetogenicresponse to moderate doses of streptozotocin in pregnant ratsand its long-term consequences in the offspringrdquo ExperimentalDiabesity Research vol 4 no 2 pp 107ndash118 2003

[6] M V Rudge F Piculo G Marini D C Damasceno I MCalderon and A P Barbosa ldquoTranslational research in ges-tational diabetes mellitus and mild gestational hyperglycemiacurrent knowledge and our experiencerdquo Arquivos Brasileiros deEndocrinologia amp Metabologia vol 57 no 7 pp 497ndash508 2013

[7] J M W Slack ldquoDevelopmental biology of the pancreasrdquoDevelopment vol 121 no 6 pp 1569ndash1580 1995

[8] F C Pan and C Wright ldquoPancreas organogenesis from bud toplexus to glandrdquo Developmental Dynamics vol 240 no 3 pp530ndash565 2011

[9] P E Lacy ldquoElectronmicroscopy of the beta cell of the pancreasrdquoThe American Journal of Medicine vol 31 no 6 pp 851ndash8591961

[10] T J Kieffer and J F Habener ldquoThe glucagon-like peptidesrdquoEndocrine Reviews vol 20 no 6 pp 876ndash913 1999

[11] R Luft S Efendic T Hokfelt O Johansson and A ArimuraldquoImmunohistochemical evidence for the localization ofsomatostatinmdashlike immunoreactivity in a cell populationof the pancreatic isletsrdquo Medical Biology vol 52 no 6 pp428ndash430 1974

[12] E Ekblad and F Sundler ldquoDistribution of pancreatic polypep-tide and peptide YYrdquo Peptides vol 23 no 2 pp 251ndash261 2002

[13] C L Prado A E Pugh-Bernard L Elghazi B Sosa-Pinedaand L Sussel ldquoGhrelin cells replace insulin-producing 120573 cellsin two mouse models of pancreas developmentrdquo Proceedings ofthe National Academy of Sciences of the United States of Americavol 101 no 9 pp 2924ndash2929 2004

[14] A Assmann C Hinault and R N Kulkarni ldquoGrowth factorcontrol of pancreatic islet regeneration and functionrdquo PediatricDiabetes vol 10 no 1 pp 14ndash32 2009

[15] M Brissova M J Fowler W E Nicholson et al ldquoAssessmentof human pancreatic islet architecture and composition by laserscanning confocal microscopyrdquo Journal of Histochemistry andCytochemistry vol 53 no 9 pp 1087ndash1097 2005

[16] O Cabrera D M Berman N S Kenyon C Ricordi PBerggren and A Caicedo ldquoThe unique cytoarchitecture ofhuman pancreatic islets has implications for islet cell functionrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 103 no 7 pp 2334ndash2339 2006

[17] L Orci and R H Unger ldquoFunctional subdivision of islets ofLangerhans and possible role of D cellsrdquoThe Lancet vol 2 no7947 pp 1243ndash1244 1975

[18] E Samols S Bonner-Weir and G C Weir ldquoIntra-islet insulin-glucagon-somatostatin relationshipsrdquo Clinics in Endocrinologyand Metabolism vol 15 no 1 pp 33ndash58 1986

[19] G Wieczorek A Pospischil and E Perentes ldquoA comparativeimmunohistochemical study of pancreatic islets in laboratoryanimals (rats dogs minipigs nonhuman primates)rdquo Experi-mental and Toxicologic Pathology vol 50 no 3 pp 151ndash1721998

[20] M Yukawa T Takeuchi T Watanabe and S Kitamura ldquoPro-portions of various endocrine cells in the pancreatic isletsof wood mice (Apodemus speciosus)rdquo Anatomia HistologiaEmbryologia vol 28 no 1 pp 13ndash16 1999

[21] S R Sujatha A Pulimood and S Gunasekaran ldquoComparativeimmunocytochemistry of isolated rat ampmonkey pancreatic isletcell typesrdquo Indian Journal of Medical Research vol 119 no 1 pp38ndash44 2004

[22] A Sanchez S Cenani and I vonLawzewitsch ldquoPancreatic isletsin Platyrrhini monkeys Callithrix jacchus Saimiri boliviensisAotus azarae and Cebus apella A cytological and immunocy-tochemical studyrdquo Primates vol 32 no 1 pp 93ndash103 1991

[23] D Pipeleers P Inrsquot Veld E Maes and M van de WinkelldquoGlucose-induced insulin release depends on functional coop-eration between islet cellsrdquo Proceedings of the National Academyof Sciences of the United States of America vol 79 no 23 I pp7322ndash7325 1982

[24] D W Hopcroft D R Mason and R S Scott ldquoStructure-function relationships in pancreatic islets support for intraisletmodulation of insulin secretionrdquo Endocrinology vol 117 no 5pp 2073ndash2080 1985


[25] P A Halban S L Powers K L George and S Bonner-WeirldquoSpontaneous reassociation of dispersed adult rat pancreaticislet cells into aggregates with three-dimensional architecturetypical of native isletsrdquoDiabetes vol 36 no 7 pp 783ndash790 1987

[26] D Bosco L Orci and P Meda ldquoHomologous but not het-erologous contact increases the insulin secretion of individualpancreatic B-cellsrdquo Experimental Cell Research vol 184 no 1pp 72ndash80 1989

[27] I Baca G E Feurle I Klempa A Ziegler and V SchusdziarraldquoMorphometry and function of islet cells after different formsof drainage at pancreatic transplantation in ratsrdquo EuropeanSurgical Research vol 22 no 3 pp 151ndash159 1990

[28] E R Trimble P A Halban C B Wollheim and A E RenoldldquoFunctional differences between rat islets of ventral and dorsalpancreatic originrdquo Journal of Clinical Investigation vol 69 no2 pp 405ndash413 1982

[29] A Jorns ldquoImmunocytochemical and ultrastructural hetero-geneities of normal and glibenclamide stimulated pancreaticbeta cells in the ratrdquoVirchowsArchiv vol 425 no 3 pp 305ndash3131994

[30] P Meda J F Denef A Perrelet and L Orci ldquoNonrandomdistribution of gap junctions between pancreatic beta-cellsrdquoTheAmerican Journal of Physiology vol 238 no 3 pp C114ndashC1191980

[31] AWojtusciszynMArmanet PMorel T Berney andD BoscoldquoInsulin secretion from human beta cells is heterogeneous anddependent on cell-to-cell contactsrdquo Diabetologia vol 51 no 10pp 1843ndash1852 2008

[32] R Jain and E Lammert ldquoCell-cell interactions in the endocrinepancreasrdquoDiabetes Obesity andMetabolism vol 11 supplement4 pp 159ndash167 2009

[33] A Edvell and P Lindstrom ldquoDevelopment of insulin secretoryfunction in young obese hyperglycemic mice (Umea obob)rdquoMetabolism Clinical and Experimental vol 44 no 7 pp 906ndash913 1995

[34] A L Fowden and D J Hill ldquoIntra-uterine programming of theendocrine pancreasrdquo The British Medical Bulletin vol 60 pp123ndash142 2001

[35] D J Pettitt P H Bennett M F Saad M A Charles RG Nelson and W C Knowler ldquoAbnormal glucose toleranceduring pregnancy in Pima Indian women long-term effects onoffspringrdquo Diabetes vol 40 no 2 pp 126ndash130 1991

[36] G V Krishnaveni S R Veena J C Hill S Kehoe S C Karatand C H D Fall ldquoIntrauterine exposure to maternal diabetesis associated with higher adiposity and insulin resistance andclustering of cardiovascular risk markers in Indian childrenrdquoDiabetes Care vol 33 no 2 pp 402ndash404 2010

[37] B Portha A Chavey and J Movassat ldquoEarly-life origins oftype 2 diabetes fetal programming of the beta-cell massrdquoExperimental Diabetes Research vol 2011 Article ID 105076 16pages 2011

[38] V Grill B Johansson P Jalkanen and U J Eriksson ldquoInfluenceof severe diabetes mellitus early in pregnancy in the rat effectson insulin sensitivity and insulin secretion in the offspringrdquoDiabetologia vol 34 no 6 pp 373ndash378 1991

[39] J Boloker S J Gertz and R A Simmons ldquoGestational diabetesleads to the development of diabetes in adulthood in the ratrdquoDiabetes vol 51 no 5 pp 1499ndash1506 2002

[40] F A Van Assche L Aerts and K Holemans ldquoThe effects ofmaternal diabetes on the offspringrdquoBaillierersquos Clinical Obstetricsand Gynaecology vol 5 no 2 pp 485ndash492 1991

[41] A Lucas ldquoProgramming by early nutrition an experimentalapproachrdquo Journal of Nutrition vol 128 no 2 supplement pp401Sndash406S 1998

[42] C Aguayo-Mazzucato C Sanchez-Soto V Godinez-Puig GGutierrez-Ospina and M Hiriart ldquoRestructuring of pancreaticislets and insulin secretion in a postnatal critical windowrdquo PLoSONE vol 1 no 1 article e35 2006

[43] A L Fowden J W Ward F P B Wooding A J ForheadandM Constancia ldquoProgramming placental nutrient transportcapacityrdquo Journal of Physiology vol 572 part 1 pp 5ndash15 2006

[44] S W J Lamberts J W Koper and J C Reubi ldquoPotential roleof somatostatin analogues in the treatment of cancerrdquo EuropeanJournal of Clinical Investigation vol 17 no 4 pp 281ndash287 1987

[45] B Setyono-Han M S Henkelman J A Foekens and J G MKlijn ldquoDirect inhibitory effects of somatostatin (analogues) onthe growth of human breast cancer cellsrdquo Cancer Research vol47 no 6 pp 1566ndash1570 1987

[46] T Nobuhiko N Miho F Mitsuko et al ldquoOctreotide-treateddiabetes accompanied by endogenous hyperinsulinemic hypo-glycemia and protein-losing gastroenteropathyrdquoCase Reports inMedicine vol 2011 Article ID 381203 8 pages 2011

[47] L Aerts and F A van Assche ldquoIslet transplantation in dia-betic pregnant rats normalizes glucose homeostasis in theiroffspringrdquo Journal of Developmental Physiology vol 17 no 6 pp283ndash287 1992

[48] M de Gasparo and R D G Milner ldquoThe timing of fetal B cellhyperplasia in diabetic rat pregnancyrdquo Diabetologia vol 19 no1 pp 54ndash57 1980

[49] E A Ryan D Liu R C Bell D T Finegood and J CrawfordldquoLong term consequences in offspring of diabetes in preg-nancy studieswith syngeneic islet-transplanted streptozotocin-diabetic ratsrdquo Endocrinology vol 136 no 12 pp 5587ndash55921995

[50] J Han J Xu Y S Long P N Epstein and Y Q Liu ldquoRatmaternal diabetes impairs pancreatic 120573-cell function in theoffspringrdquo The American Journal of PhysiologymdashEndocrinologyand Metabolism vol 293 no 1 pp E228ndashE236 2007

[51] C J Zeng L Zhang and H X Yang ldquoEffects of severehyperglycaemia in pregnancy and early overfeeding on isletdevelopment and insulin resistancerdquo Zhonghua Fu Chan Ke ZaZhi vol 45 no 9 pp 658ndash663 2010

[52] K C Marchand E J Arany and D J Hill ldquoEffects ofatorvastatin on the regeneration of pancreatic 120573-cells afterstreptozotocin treatment in the neonatal rodentrdquoTheAmericanJournal of PhysiologymdashEndocrinology and Metabolism vol 299no 1 pp E92ndashE100 2010

[53] R C S Branco J C de Oliveira S Grassiolli et al ldquoMaternalprotein malnutrition does not impair insulin secretion frompancreatic islets of offspring after transplantation into diabeticratsrdquo PLoS ONE vol 7 no 2 Article ID e30685 2012

[54] A B Aref O M Ahmed L A Ali and M Semmler ldquoMaternalrat diabetes mellitus deleteriously affects insulin sensitivity andbeta-cell function in the offspringrdquo Journal of Diabetes Researchvol 2013 Article ID 429154 10 pages 2013

[55] I L Iessi Y K Sinzato I M P Calderon M V C Rudge andD C Damasceno ldquoPancreatic islet hormonal triad in diabeticpregnant rats and their offspringrdquo PLoS ONE In press

[56] J L Evans B A Maddux and I D Goldfine ldquoThe molecularbasis for oxidative stress-induced insulin resistancerdquo Antioxi-dants and Redox Signaling vol 7 no 7-8 pp 1040ndash1052 2005


[57] F Folli D Corradi P Fanti et al ldquoThe role of oxidativestress in the pathogenesis of type 2 diabetes mellitus micro-andmacrovascular complications avenues for a mechanistic-basedtherapeutic approachrdquo Current Diabetes Reviews vol 7 no 5pp 313ndash324 2011

[58] E K Kim and E J Choi ldquoPathological roles of MAPK signalingpathways in human diseasesrdquo Biochimica et Biophysica ActamdashMolecular Basis of Disease vol 1802 no 4 pp 396ndash405 2010

[59] I Sigala P Zacharatos D Toumpanakis et al ldquoMAPKs andNF-120581B differentially regulate cytokine expression in the diaphragmin response to resistive breathing the role of oxidative stressrdquoTheAmerican Journal of PhysiologymdashRegulatory Integrative andComparative Physiology vol 300 no 5 pp R1152ndashR1162 2011

[60] G Muscogiuri A B Salmon C Aguayo-Mazzucato et alldquoGenetic disruption of SOD1 gene causes glucose intoleranceand impairs 120573-cell functionrdquo Diabetes vol 62 no 12 pp 4201ndash4207 2013

[61] National Diabetes Data Group ldquoClassification and diagnosis ofdiabetes and other categories of glucose intolerancerdquo Diabetesvol 28 no 12 pp 1039ndash1057 1979

[62] WHO Expert Committee on Diabetes Mellitus TechnicalReport Series 646 Second Report World Health OrganisationGeneva Switzerland 1980

[63] R Kahn ldquoReport of the expert committee on the diagnosis andclassification of diabetes mellitusrdquo Diabetes Care vol 20 no 7pp 1183ndash1197 1997

[64] World Health Organisation Definition Diagnosis and Classi-fication of Diabetes Mellitus and Its Complications Report ofa WHO ConsultationmdashPart 1 Diagnosis and Classification ofDiabetesMellitus WorldHealth Organisation Geneva Switzer-land 1999

[65] N Unwin J Shaw P Zimmet and K G M M AlbertildquoImpaired glucose tolerance and impaired fasting glycaemiathe current status on definition and interventionrdquo DiabeticMedicine vol 19 no 9 pp 708ndash723 2002

[66] D T Ward S K Yau A P Mee et al ldquoFunctional molecularand biochemical characterization of streptozotocin-induceddiabetesrdquo Journal of the American Society of Nephrology vol 12no 4 pp 779ndash790 2001

[67] S Lenzen ldquoThe mechanisms of alloxan- and streptozotocin-induced diabetesrdquoDiabetologia vol 51 no 2 pp 216ndash226 2008

[68] B Portha C Levacher L Picon andG Rosselin ldquoDiabetogeniceffect of streptozotocin in the rat during the perinatal periodrdquoDiabetes vol 23 no 11 pp 889ndash895 1974

[69] S Lenzen M Tiedge A Jorns and R Munday ldquoAlloxanderivatives as a tool for the elucidation of the mechanism ofthe diabetogenic action of alloxanrdquo in Lessons from AnimalDiabetes E Shafrir Ed pp 113ndash122 Birkhauser Boston MassUSA 1996

[70] R N Arison E I Ciaccio M S Glitzer J A Cassaro andM P Pruss ldquoLight and electron microscopy of lesions in ratsrendered diabetic with streptozotocinrdquo Diabetes vol 16 no 1pp 51ndash56 1967

[71] U J Eriksson L A H Borg J Cederberg et al ldquoPathogenesisof diabetes-induced congenital malformationsrdquo Upsala Journalof Medical Sciences vol 105 no 2 pp 53ndash84 2000

[72] U J Eriksson J Cederberg and P Wentzel ldquoCongenitalmalformations in offspring of diabetic mothersmdashanimal andhuman studiesrdquo Reviews in Endocrine and Metabolic Disordersvol 4 no 1 pp 79ndash93 2003

[73] D C Damasceno G T Volpato M C Ide R Aguilar and MV C Rudge ldquoEffect of Bauhinia forficata extract in diabeticpregnant rats maternal repercussionsrdquo Phytomedicine vol 11no 2-3 pp 196ndash201 2004

[74] M V C Rudge D C Damasceno G T Volpato F C GAlmeida I M P Calderon and I P Lemonica ldquoEffect ofGinkgo biloba on the reproductive outcome and oxidative stressbiomarkers of streptozotocin-induced diabetic ratsrdquo BrazilianJournal of Medical and Biological Research vol 40 no 8 pp1095ndash1099 2007

[75] G T Volpato D C DamascenoMV C Rudge C R Padovaniand I M P Calderon ldquoEffect of Bauhinia forficata aqueousextract on the maternal-fetal outcome and oxidative stressbiomarkers of streptozotocin-induced diabetic ratsrdquo Journal ofEthnopharmacology vol 116 no 1 pp 131ndash137 2008

[76] S de SouzaMda P H O Lima Y K Sinzato M V C Rudge OC M Pereira and D C Damasceno ldquoEffects of cigarette smokeexposure on pregnancy outcome and offspring of diabetic ratsrdquoReproductive BioMedicine Online vol 18 no 4 pp 562ndash5672009

[77] S de Souza Mda Y K Sinzato P H O Lima I M P CalderonM V C Rudge and D C Damasceno ldquoOxidative stress statusand lipid profiles of diabetic pregnant rats exposed to cigarettesmokerdquo Reproductive BioMedicine Online vol 20 no 4 pp547ndash552 2010

[78] K Tsuji T Taminato M Usami et al ldquoCharacteristic featuresof insulin secretion in the streptozotocin-induced NIDDM ratmodelrdquo Metabolism Clinical and Experimental vol 37 no 11pp 1040ndash1044 1988

[79] H Merzouk S Madani D C Sari J Prost M Bouchenak andJ Belleville ldquoTime course of changes in serum glucose insulinlipids and tissue lipase activities inmacrosomic offspring of ratswith streptozotocin-induced diabetesrdquo Clinical Science vol 98no 1 pp 21ndash30 2000

[80] Y K Sinzato P H Lima K E de Campos A C I Kiss M VC Rudge and D C Damascene ldquoNeonatally-induced diabeteslipid profile outcomes and oxidative stress status in adult ratsrdquoRevista da Associacao Medica Brasileira vol 55 no 4 pp 384ndash388 2009

[81] D C Damasceno A C I Kiss Y K Sinzato et al ldquoMaternal-fetal outcome lipid profile and oxidative stress of diabeticrats neonatally exposed to streptozotocinrdquo Experimental andClinical Endocrinology and Diabetes vol 119 no 7 pp 408ndash4132011

[82] J Y Uriu-Hare C L Keen E A Applegate and J S SternldquoThe influence of moderate exercise in diabetic and normalpregnancy on maternal and fetal outcome in the ratrdquo LifeSciences vol 45 no 7 pp 647ndash654 1989

[83] A Bueno Y K Sinzato M J Sudano et al ldquoShort and long-term repercussions of the experimental diabetes in embryofetaldevelopmentrdquoDiabetesMetabolismResearch andReviews 2014

[84] D C Damasceno H P Silva G F Vaz et al ldquoDiabetic ratsexercised prior to and during pregnancymaternal reproductiveoutcome biochemical profile and frequency of fetal anomaliesrdquoReproductive Sciences vol 20 no 7 pp 730ndash738 2013

[85] FH SaitoDCDamasceno BDallaqua et al ldquoHeat shock pro-tein production and immunity and altered fetal development indiabetic pregnant ratsrdquo Cell Stress and Chaperones vol 18 no 1pp 25ndash33 2013

[86] P H O Lima Y K Sinzato R B Gelaleti I M P Calderon MV C Rudge and D C Damasceno ldquoGenotoxicity evaluationin severe or mild diabetic pregnancy in laboratory animalsrdquo


Experimental and Clinical Endocrinology and Diabetes vol 120no 5 pp 303ndash307 2012

[87] F Piculo G Marini A M Barbosa et al ldquoUrethral striatedmuscle and extracellular matrix morphological characteristicsamong mildly diabetic pregnant rats translational approachrdquoInternational Urogynecology Journal vol 25 no 3 pp 403ndash4152014

[88] A C I Kiss B Woodside Y K Sinzato et al ldquoNeonatallyinducedmild diabetes influence on development behavior andreproductive function of female Wistar ratsrdquo Diabetology andMetabolic Syndrome vol 5 no 1 article 61 2013

[89] A P Spada D C Damasceno Y K Sinzato et al ldquoOxidativestress in maternal blood and placenta from mild diabetic ratsrdquoReproductive Sciences 2014

[90] B Dallaqua F H Saito T Rodrigues et al ldquoAzadirachta indicatreatment on the congenitalmalformations of fetuses from ratsrdquoJournal of Ethnopharmacology vol 150 no 3 pp 1109ndash11132013

[91] B Dallaqua F H Saito T Rodrigues et al ldquoTreatment withAzadirachta indica in diabetic pregnant rats negative effects onmaternal outcomerdquo Journal of Ethnopharmacology vol 143 no3 pp 805ndash811 2012

[92] A C I Kiss B Woodside L F Felıcio J Anselmo-Franciand D C Damasceno ldquoImpact of maternal mild hyperglycemiaon maternal care and offspring development and behavior ofWistar ratsrdquo Physiology and Behavior vol 107 no 3 pp 292ndash300 2012

[93] Y K Sinzato G T Volpato I L Iessi et al ldquoNeonatally inducedmild diabetes in rats and its effect on maternal placental andfetal parametersrdquo Experimental Diabetes Research vol 2012Article ID 108163 7 pages 2012

[94] S Georgia and A Bhushan ldquo120573 cell replication is the primarymechanism for maintaining postnatal 120573 cell massrdquo Journal ofClinical Investigation vol 114 no 7 pp 963ndash968 2004

[95] X D Liang Y Y Guo M Sun et al ldquoStreptozotocin-inducedexpression of Ngn3 and Pax4 in neonatal rat pancreatic 120572-cellsrdquoWorld Journal of Gastroenterology vol 17 no 23 pp 2812ndash28202011

[96] R J Goss ldquoModes of growth and regeneration mechanismsregulation distributionrdquo in Human Growth A ComprehensiveTreatise F Falkner and J M Tanner Eds vol 1 pp 3ndash26Plenum Press New York NY USA 2nd edition 1986

[97] S Bonner-Weir D F Trent R N Honey and G C WeirldquoResponses of neonatal rat islets to streptozotocin limited B-cell regeneration and hyperglycemiardquoDiabetes vol 30 no 1 pp64ndash69 1981

[98] S Bonner-Weir and G C Weir ldquoNew sources of pancreatic 120573-cellsrdquo Nature Biotechnology vol 23 no 7 pp 857ndash861 2005

[99] KMinami and S Seino ldquoRegeneration of the pancreasrdquoNipponRinsho vol 66 no 5 pp 926ndash931 2008

[100] P Collombat AMansouri J Hecksher-Soslashrensen et al ldquoOppos-ing actions of Arx and Pax4 in endocrine pancreas develop-mentrdquo Genes and Development vol 17 no 20 pp 2591ndash26032003

[101] L Scaglia C J Cahill D T Finegood and S Bonner-WeirldquoApoptosis participates in the remodeling of the endocrinepancreas in the neonatal ratrdquo Endocrinology vol 138 no 4 pp1736ndash1741 1997

[102] R W Oppenheim ldquoCell death during development of thenervous systemrdquo Annual Review of Neuroscience vol 14 pp453ndash501 1991

[103] H S R Coles J F Burne and M C Raff ldquoLarge-scale normalcell death in the developing rat kidney and its reduction byepidermal growth factorrdquo Development vol 118 no 3 pp 777ndash784 1993

[104] T Terada and Y Nakanuma ldquoDetection of apoptosis andexpression of apoptosis-related proteins during human intra-hepatic bile duct developmentrdquoTheAmerican Journal of Pathol-ogy vol 146 no 1 pp 67ndash74 1995

[105] A J Blaschke K Staley and J Chun ldquoWidespread programmedcell death in proliferative and postmitotic regions of the fetalcerebral cortexrdquo Development vol 122 no 4 pp 1165ndash11741996

[106] B Portha O Blondel P Serradas et al ldquoThe rat models ofnon-insulin dependent diabetes induced by neonatal strepto-zotocinrdquo Diabete et Metabolisme vol 15 no 2 pp 61ndash75 1989

[107] S Bonner-Weir D Deery J L Leahy andG CWeir ldquoCompen-satory growth of pancreatic 120573-cells in adult rats after short-termglucose infusionrdquo Diabetes vol 38 no 1 pp 49ndash53 1989

[108] S Bonner-Weir ldquoRegulation of pancreatic 120573-cell mass in vivordquoRecent Progress in Hormone Research vol 49 no 1 pp 91ndash1041994

[109] GGradwohl A DierichM LeMeur and F Guillemot ldquoNeuro-genin3 is required for the development of the four endocrine celllineages of the pancreasrdquo Proceedings of the National Academy ofSciences of the United States of America vol 97 no 4 pp 1607ndash1611 2000

[110] M Jenny C Uhl C Roche et al ldquoNeurogenin3 is differentiallyrequired for endocrine cell fate specification in the intestinaland gastric epitheliumrdquo The EMBO Journal vol 21 no 23 pp6338ndash6347 2002

[111] G Gu J R Brown and D A Melton ldquoDirect lineage tracingreveals the ontogeny of pancreatic cell fates during mouseembryogenesisrdquoMechanisms of Development vol 120 no 1 pp35ndash43 2003

[112] S W Li V Koya Y Li et al ldquoPancreatic duodenal homeobox 1protein is a novelΒ-cell-specific autoantigen for type I diabetesrdquoLaboratory Investigation vol 90 no 1 pp 31ndash39 2010

[113] S B Smith H C Ee J R Conners andM S German ldquoPaired-homeodomain transcription factor PAX4 acts as a transcrip-tional repressor in early pancreatic developmentrdquo Molecularand Cellular Biology vol 19 no 12 pp 8272ndash8280 1999

[114] C Dohrmann P Gruss and L Lemaire ldquoPax genes and thedifferentiation of hormone-producing endocrine cells in thepancreasrdquoMechanisms of Development vol 92 no 1 pp 47ndash542000

[115] M Courtney E Gjernes N Druelle et al ldquoThe inactivationof Arx in pancreatic 120572-cells triggers their neogenesis andconversion into functional 120573-like cellsrdquo PLoS Genetics vol 9no 10 Article ID e1003934 2013

[116] D G Garcıa and D R Garcıa ldquoAvances en la patogenesis de laembriopatıa diabeticardquo Revista Medica de Chile vol 137 no 12pp 1627ndash1635 2009

[117] T R Moore ldquoDiabetes in pregnancyrdquo in Maternal FetalMedicine Principles and Practice R K Creasy and R ResnikEds pp 964ndash995 WB Saunders Philadelphia Pa USA 4thedition 1999

[118] U J Eriksson ldquoCongenital anomalies in diabetic pregnancyrdquoSeminars in Fetal and Neonatal Medicine vol 14 no 2 pp 85ndash93 2009

[119] S Zabihi and M R Loeken ldquoUnderstanding diabetic teratoge-nesis where are we now and where are we goingrdquo Birth Defects


Research A Clinical andMolecular Teratology vol 88 no 10 pp779ndash790 2010

[120] P White ldquoPregnancy complicating diabetesrdquo The AmericanJournal of Medicine vol 7 no 5 pp 609ndash616 1949

[121] N Freinkel E Ogata and B E Metzger ldquoThe offspring of themother with diabetesrdquo inDiabetesMellitusTheory and PracticeH Rifkin and D Porte Jr Eds pp 651ndash660 Elsevier ScienceNew York NY USA 1990

[122] K Fuhrmann H Reiher K Semmler and E Glockner ldquoTheeffect of intensified conventional insulin therapy before andduring pregnancy on the malformation rate in offspring ofdiabeticmothersrdquoExperimental andClinical Endocrinology vol83 no 2 pp 173ndash177 1984

[123] M M Cohen Jr and K Shiota ldquoTeratogenesis of holoprosen-cephalyrdquoTheAmerican Journal of Medical Genetics vol 109 no1 pp 1ndash15 2002

[124] A Correa S M Gilboa L M Besser et al ldquoDiabetes mellitusand birth defectsrdquo The American Journal of Obstetrics andGynecology vol 199 no 3 pp 237e1ndash237e9 2008

[125] C Calciu S Kubow and H M Chan ldquoInteractive dysmor-phogenic effects of toxaphene or toxaphene congeners andhyperglycemia on cultured whole rat embryos during organo-genesisrdquo Toxicology vol 175 no 1ndash3 pp 153ndash165 2002

[126] D C Damasceno G T Volpato I M P Calderon andM V CRudge ldquoOxidative stress and diabetes in pregnant ratsrdquo AnimalReproduction Science vol 72 no 3-4 pp 235ndash244 2002

[127] M Gareskog J Cederberg U J Eriksson and P WentzelldquoMaternal diabetes in vivo and high glucose concentrationin vitro increases apoptosis in rat embryosrdquo ReproductiveToxicology vol 23 no 1 pp 63ndash74 2007

[128] M Hod S Star J Passonneau T G Unterman andN FreinkelldquoGlucose-induced dysmorphogenesis in the cultured rat con-ceptus prevention by supplementation with myo-inositolrdquoIsrael Journal of Medical Sciences vol 26 no 10 pp 541ndash5441990

[129] U J Eriksson P Naeser and S E Brolin ldquoIncreased accumula-tion of sorbitol in offspring of manifest diabetic ratsrdquo Diabetesvol 35 no 12 pp 1356ndash1363 1986

[130] E Pinter E A Reece C Z Leranth et al ldquoYolk sac failurein embryopathy due to hyperglycemia ultrastructural analysisof yolk sac differentiation associated with embryopathy in ratconceptuses under hyperglycemic conditionsrdquo Teratology vol33 no 1 pp 73ndash84 1986

[131] A S Goldman and M P Goto ldquoBiochemical basis of thediabetic embryopathyrdquo Israel Journal ofMedical Sciences vol 27no 8-9 pp 469ndash477 1991

[132] Z J Hagay Y Weiss I Zusman et al ldquoPrevention of diabetes-associated embryopathy by overexpression of the free radicalscavenger copper zinc superoxide dismutase in transgenicmouse embryosrdquoThe American Journal of Obstetrics and Gyne-cology vol 173 no 4 pp 1036ndash1041 1995

[133] E Herrera ldquoImplications of dietary fatty acids during preg-nancy on placental fetal and postnatal developmentmdasha reviewrdquoPlacenta vol 23 supplement A no 1 pp S9ndashS19 2002

[134] E A Reece Y K Wu Z Zhao and D DhanasekaranldquoDietary vitamin and lipid therapy rescues aberrant signalingand apoptosis and prevents hyperglycemia-induced diabeticembryopathy in ratsrdquo The American Journal of Obstetrics andGynecology vol 194 no 2 pp 580ndash585 2006

[135] Y I Cha L Solnica-Krezel and R N DuBois ldquoFishingfor prostanoids deciphering the developmental functions of

cyclooxygenase-derived prostaglandinsrdquo Developmental Biol-ogy vol 289 no 2 pp 263ndash272 2006

[136] R Piddington J Joyce P Dhanasekaran and L Baker ldquoDia-betes mellitus affects prostaglandin E2 levels in mouse embryosduring neurulationrdquo Diabetologia vol 39 no 8 pp 915ndash9201996

[137] P Wentzel N Welsh and U J Eriksson ldquoDevelopmental dam-age increased lipid peroxidation diminished cyclooxygenase-2 gene expression and lowered prostaglandin E2 levels in ratembryos exposed to a diabetic environmentrdquo Diabetes vol 48no 4 pp 813ndash820 1999

[138] S Akazawa ldquoDiabetic embryopathy studies using a rat embryoculture system and an animal modelrdquo Congenital Anomaliesvol 45 no 3 pp 73ndash79 2005

[139] M Brownlee ldquoBiochemistry and molecular cell biology ofdiabetic complicationsrdquo Nature vol 414 no 6865 pp 813ndash8202001

[140] S El-Hage and S M Singh ldquoTemporal expression of genesencoding free radical-metabolizing enzymes is associated withhigher mRNA levels during in utero development in micerdquoDevelopmental Genetics vol 11 no 2 pp 149ndash159 1990

[141] U J Eriksson and L A H Borg ldquoDiabetes and embryonicmalformations role of substrate-induced free-oxygen radicalproduction for dysmorphogenesis in cultured rat embryosrdquoDiabetes vol 42 no 3 pp 411ndash419 1993

[142] M Kinalski A Sledziewski B Telejko I Kowalska A Kre-towski and I Kinalska ldquoEvaluation of lipid peroxidation andacid-base status in cord blood of newborns after diabetes inpregnancyrdquo Przeglad Lekarski vol 58 no 3 pp 120ndash123 2001

[143] A Ornoy ldquoBiomarkers of maternal diabetes and its complica-tion in pregnancyrdquo Reproductive Toxicology vol 34 no 2 pp174ndash179 2012

[144] P Wentzel and U J Eriksson ldquoAltered gene expression in ratcranial neural crest cells exposed to a teratogenic glucose con-centration in vitro-paradoxical downregulation of antioxidativedefense genesrdquo Birth Defects Research BmdashDevelopmental andReproductive Toxicology vol 92 no 5 pp 487ndash497 2011

[145] I Emerit ldquoReactive oxygen species chromosomemutation andcancer possible role of clastogenic factors in carcinogenesisrdquoFree Radical Biology and Medicine vol 16 no 1 pp 99ndash1091994

[146] I Emerit ldquoClastogenic factors detection and assayrdquoMethods inEnzymology vol 186 pp 555ndash564 1990

[147] I D Young ldquoCongenital malformations incidence and geneticsof congenital malformationsrdquo in Prenatal Diagnosis and Screen-ing D J H Brock C H Rodeck and M A Ferguson-SmithEds pp 171ndash188 Churchill Livingstone London UK 1992

[148] A P Breen and J A Murphy ldquoReactions of oxyl radicals withDNArdquoFree Radical Biology andMedicine vol 18 no 6 pp 1033ndash1077 1995

[149] L J Marnett ldquoOxyradicals and DNA damagerdquo Carcinogenesisvol 21 no 3 pp 361ndash370 2000

[150] T G Newcombe and L A Loeb ldquoMechanism of mutagenicityof oxidatively-modified basesrdquo in Molecular Biology of FreeRadicals in HumanDisease O I Aruoma and B Halliwell Edspp 139ndash166 OICA International Paris France 1998

[151] A Azqueta S Shaposhnikov and A R Collins ldquoDNA oxida-tion investigating its key role in environmental mutagenesiswith the comet assayrdquo Mutation ResearchmdashGenetic Toxicologyand Environmental Mutagenesis vol 674 no 1-2 pp 101ndash1082009


[152] S Loft K Vistisen M Ewertz A Tjonneland K Overvadand H E Poulsen ldquoOxidative DNA damage estimated by8-hydroxydeoxyguanosine excretion in humans influence ofsmoking gender and body mass indexrdquo Carcinogenesis vol 13no 12 pp 2241ndash2247 1992

[153] M Erhola S Toyokuni K Okada et al ldquoBiomarker evidenceof DNA oxidation in lung cancer patients association of uri-nary 8-hydroxy-21015840-deoxyguanosine excretion with radiother-apy chemotherapy and response to treatmentrdquo FEBS Lettersvol 409 no 2 pp 287ndash291 1997

[154] C Qiu K Hevner D Abetew D A Enquobahrie and MA Williams ldquoOxidative DNA damage in early pregnancy andrisk of gestational diabetes mellitus a pilot studyrdquo ClinicalBiochemistry vol 44 no 10-11 pp 804ndash808 2011

[155] A R Collins S J Duthie and V L Dobson ldquoDirect enzymicdetection of endogenous oxidative base damage in humanlymphocyte DNArdquo Carcinogenesis vol 14 no 9 pp 1733ndash17351993

[156] A R Collins M Dusinska C M Gedik and R StetinaldquoOxidative damage to DNA do we have a reliable biomarkerrdquoEnvironmental Health Perspectives vol 104 supplement 3 pp465ndash469 1996

[157] B T Mossman C M Ireland M Filipak S LeDoux and G LWilso ldquoComparative interactions of streptozotocin and chloro-zotocin with DNA of an insulin-secreting cell line (RINr)rdquoDiabetologia vol 29 no 3 pp 186ndash191 1986

[158] C C Pettepher S P LeDoux V A Bohr and G L WilsonldquoRepair of alkali-labile sites within the mitochondrial DNA ofRINr 38 cells after exposure to the nitrosourea streptozotocinrdquoThe Journal of Biological Chemistry vol 266 no 5 pp 3113ndash31171991

[159] D C Damasceno G T Volpato Y K Sinzato et al ldquoGenotox-icity and fetal abnormality in streptozotocin-induced diabeticrats exposed to cigarette smoke prior to and during pregnancyrdquoExperimental and Clinical Endocrinology and Diabetes vol 119no 9 pp 549ndash553 2011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Anatomy Research International

PeptidesInternational Journal of


Hindawi Publishing Corporation httpwwwhindawicom

International Journal of

Volume 2014

Zoology


Molecular Biology International

GenomicsInternational Journal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014


BioinformaticsAdvances in

Marine BiologyJournal of



Signal TransductionJournal of


BioMed Research International

Evolutionary BiologyInternational Journal of



Biochemistry Research International

ArchaeaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014


Genetics Research International


Advances in

Virolog y

Hindawi Publishing Corporationhttpwwwhindawicom

Nucleic AcidsJournal of

Volume 2014

Stem CellsInternational



Enzyme Research



Microbiology


Acquired processes include pancreatitis trauma infectionpancreatectomy and pancreatic carcinoma (such as cysticfibrosis) However for the clinician and patient it is lessimportant to label the particular type of diabetes than it isto understand the pathogenesis of hyperglycemia and to treatit effectively [1]

Research in health has been improving the quality ofmedical care influencing health policies and ensuring patientsafety Translational research is an important tool that allowsresearchers in clinical practices to establish knowledge andimplement the results [2] Translational research covers twoareas One is the process of applying discoveries generatedduring research in the laboratory and in preclinical studies tothe development of trials and studies in humans The secondarea of translation concerns research aimed at enhancingthe adoption of best practices in the community The cost-effectiveness of prevention and treatment strategies is alsoan important part of translational science [3] According tothis definition translational research is part of a unidirec-tional continuum in which research findings move from theresearcherrsquos bench to the patientrsquos bedside and the commu-nity In the continuum the first stage of translational research(T1) transfers knowledge from basic research to clinicalresearch while the second stage (T2) transfers findings fromclinical studies or clinical trials to practice settings andcommunities where the findings improve health [4] Dueto ethical issues involving human studies that can requireinvasive aspects and themultiplicity of uncontrolled variablesthat can alter the uterine environment during clinical studies[5] it is necessary to use animal models to better understanddiabetic pathophysiology [6] Thus this review aimed togather information about pathophysiological mechanismsand fetal outcomes in streptozotocin-induced diabetic rats

2 Pancreatic Islets Structure and FunctionThe pancreas is a complex organ that consists of twofunctionally and morphologically distinct cell populationsderived from the endoderm The exocrine pancreas consistsof acinar cells that secret digestive enzymes such as amylaseslipases proteases and nucleases which are emptied into thepancreatic duct through an elaborately branched networkof tubules composed of epithelial cells Acinar cells alsoproduce bicarbonate ions and electrolytes which togetherwith exocrine enzymes are transported through the mainduct into the duodenum where they contribute to foodprocessing [7 8]

Groups of endocrine cells called pancreatic islets repre-sent the endocrine portion which composes only approx-imately 2 of the pancreas Each islet is composed ofat least five types of cells including insulin-producing 120573cells (65ndash80) [9] glucagon-releasing 120572 cells (15ndash20)[10] somatostatin-producing 120575 cells (3ndash10) [11] pancre-atic polypeptide-containing PP cells (1) [12] and ghrelin-containing 120576 cells [13] All of these hormones are involvedin the regulation of nutrient metabolism and glucose home-ostasis [14] The cytoarchitecture of rodent and human isletspresents notable differences [15 16] In islets from mice andother rodents the 120573 cells are predominately located in the

central core with 120572 and 120575 cells localized in the peripheryforming amantle [17ndash21] In human andmonkey islets120572 cellsare not localized in the periphery but rather are dispersedthroughout the islet [15 16 19 21 22]

There are several lines of evidence that pancreatic isletscannot be considered aggregates of cells It was well estab-lished more than 20 years ago that the integrated secretoryresponses of isolated islets are greater than those of dispersedislet cells suggesting that cell-to-cell interactions are nec-essary for the normal secretory function of the endocrinepancreas [23ndash27]

However there are no reports regarding the effectendocrine hormones in the diabetic environment Severalstudies have emphasized the importance of interactionsamong the different cells [28 29] and between cells of thesame type [29 30] in metabolic control In normal isletsthe insulin-producing cells are under the influence of otherhormone-secreting islet cells Glucagon is known to enhanceboth insulin and somatostatin secretion while somatostatinexerts an inhibitory effect on insulin and glucagon secretion[31 32] Communication among these hormones is importantto maintain physiological balance and any disorder in thissystem would result in excessive blood glucose levels forexample damaging the organism

Hyperglycemia during pregnancy impairs the intrauter-ine environment affecting normal fetal development andresulting in long-term effects on the function and structureof fetal pancreatic islets [33 34] This status increases theoffspringrsquos risk of obesityadiposity glucose intolerance andtype 2 diabetes later in life [1 35ndash37] Animal studies haveshown that the offspring of diabetic rats can be insulin resis-tant [38 39] and diabetic [39 40] Studies support the conceptthat developing organs have critical periods of intense struc-tural and functional reorganization In the case of the pan-creas this circumstance may render it vulnerable to environ-mental stimuli [41 42] which may lead to consequences forthe next generation [43] and future studies should considerthe hormone interactions involved for this glucose control

The literature shows that the administration of pancreatichormones analogs (insulin glucagon and somatostatin) in invitro studies is important to investigate the mechanisms ofhormonal synthesis and secretion in an isolatedmanner [44ndash46] In addition insulin is the most studied hormone in thematernal and fetal organism in an attempt to understand therepercussions of hyperglycemia [47ndash54] In our laboratorywe hypothesized that glucoregulatory hormones such asglucagon and somatostatin in addition to insulin are relevantfor embryo-fetal development and diabetes-derived alter-ations We performed an experimental study in rats to eval-uate the importance of the endocrine pancreatic hormonaltriad in maternal fetal and neonatal organisms exposed toa hyperglycemic intrauterine environment According to ourresults somatostatin levels were altered in all developmentalpoints studied showing that pancreatic alteration inmaternaland fetal organisms persisted in the neonatal period Theseresults suggest that somatostatin might be a predictor ofadverse effects in adulthood In fact our data show the impor-tance of studying hormonal interactions in the endocrinepancreas to understand the pathophysiological mechanisms



































7 Conclusion




Acknowledgment


References















































































































































































Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology



































7 Conclusion




Acknowledgment


References















































































































































































Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology























































































































































Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology

review article streptozotocin-induced diabetes models:...

Documents