Maternal green tea extract supplementation to rats fed a high-fat diet ameliorates insulin resistance in adult male offspring
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overweight and obesity in women of child-bearing age , it ispertinent to investigate the role of maternal overnutrition and
for many cultures and is consumed worldwide. The health benefits oftea have appeared in numerous reviews, and the effects are usually
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stryexplore potential intervening strategies. To this end, emergingevidence  suggests that the increased risk of chronic disease inlater life is related, at least in part, to the process of developmentalprogramming originally proposed by Hales and Baker to explain theimpact of undernutrition in utero and early postnatal life .
Numerous studies have demonstrated a potential role forbioactive food components (BFCs) as an adjunct to the treatment ofobesity and metabolic syndrome [10,11]. Common to these BFCs isthat most possess strong antioxidant properties. Indeed, a recentstudy had demonstrated a protective role of supplementing antiox-
attributable to the catechins [14,15]. Epigallocatechin gallate (EGCG)is the most abundant catechin in green tea. Being an insulinpotentiating factor and antioxidant, EGCG is postulated to play arole in preventing metabolic syndrome . Dietary EGCG supple-mentation reduced body fat in male mice , and EGCG injected intolean and obese Zucker rats significantly reduced blood glucose andinsulin levels . Dietary EGCG supplementation also reduced bodyweight as well as plasma glucose, insulin and lipids in human [18,19].
To our best knowledge, the effect of GT on developmentalprogramming has not been studied. Hence, this study aimed to testrats born to GT dams were 57%, 23% and 26% lower, accompanied by improved gene/protein expressions related to lipid and glucose metabolism, compared withthe HF/HF rats (Pb.05). Although HF/GT1 and HF/GT2 rats had lower serum NEFA, their insulin and IRI were comparable to HF/HF rats. This study shows thatmetabolic derangements induced by an overnourished mother could be offset by supplementing GT to the maternal diet and that this approach is more effectivethan giving GT to offspring since weaning. Hence, adverse effects of developmental programming are reversible, at least in part, by supplementing bioactive foodcomponent(s) to the mother's diet. 2012 Elsevier Inc. All rights reserved.
Keywords: Developmental programming; High-fat; Green tea; Insulin resistance; Offspring
A growing body of literature suggests a causal link betweenmaternal and child obesity . With the increasing proportion of
supplement obviously is critical because others have reportedincrease in adiposity in young rats fed an obesogenic diet whendams received excessive amount of vitamin during pregnancy .
Our interest in tea stems from the fact that it is a popular beverageGT2, GT1/HF and GT2/HF). At week 13, they had similar weight but insulin resupplementation can alleviate metabolic derangements in high-fat-diet-fed rats born of obese dams. Female SpragueDawley rats were fed low-fat (LF, 7%),high-fat (HF, 30%) or HF diet containing 0.75% or 1.0% GT extract (GT1, GT2) prior to conception and throughout gestation and lactation. Both doses of GTsignificantly improved metabolic parameters of HF-fed lactating dams (Pb.05). Birth weight and litter size of offspring from HF dams were similar, but GTsupplementation led to lighter pups on day 21 (Pb.05). The weaned male pups received HF, GT1 or GT2 diet (dam/pup diet groups: LF/HF, HF/HF, HF/GT1, HF/
sistance index (IRI), serum nonesterified fatty acid (NEFA) and liver triglyceride ofMaternal green tea extract supplementainsulin resistance in
Shiying Li, Iris M.Y
Food and Nutritional Science Division, School of Biological Scienc
Received 3 May 2011; received in revised form
Maternal overnutrition is associated with increased risk of metabolic disor
Journal of Nutritional Biochemiidants to the dam's diet. In the latter study, maternal-obesity-inducedoxidative imbalance was restored when Western-diet-fed damsreceived a mixture of antioxidant supplement, and that benefit inoffspring was a decrease in adiposity . The type of vitamin
This study was supported by an HKU grant. Corresponding author. Tel.: +852 2299 0807; fax: +852 2559 9114.E-mail address: email@example.com (E.T.S. Li).
0955-2863/$ - see front matter 2012 Elsevier Inc. All rights reserved.http://dx.doi.org/10.1016/j.jnutbio.2011.11.008n to rats fed a high-fat diet amelioratesult male offspring
e, Edmund T.S. Li
University of Hong Kong, Hong Kong, People's Republic of China
ovember 2011; accepted 23 November 2011
n the offspring. This study tested the hypothesis that maternal green tea (GT)
23 (2012) 16551660the hypothesis that the beneficial effects of green tea extract (GTE) onmetabolic control of dams would pass on to the offspring as adults,that is, themetabolic derangements in offspring born to high-fat-diet-fed dams could be ameliorated if dams are supplemented with GTE.Different frommost programming studies inwhich the offspringwerenormally fed a control diet, in the present study, the male pups werealso given a high-fat diet. This two-generation fat exposure designaims to simulate the worse case scenario in our modern societies. We
first established the impacts of maternal high fat in the presence andabsence of GTE supplementation on dams and then compared theeffects of prenatal vs. postweaning GTE supplementation on maleoffspring. Males were selected because the programming effects oninsulin response appear to be gender specific, with insulin resistanceand hyperinsulinemia readily observed in male pups born of obesedams . In this study, two doses of GTE were added to the maternalHF diet or postweaning HF diet separately, generating six maternal/postweaning diet combinations: LF/HF, HF/HF, HF/GT1, HF/GT2,GT1/HF and GT2/HF pups. The glucose, insulin concentration andlipid profile of adult male were monitored, and changes in theirmetabolic regulation by maternal dietary manipulations weredescribed in the context of relevant mRNA/protein expressions inliver, adipose tissues and muscle.
2. Materials and methods
2.1. GTE and experimental diets
1656 S. Li et al. / Journal of Nutritional BiochThe GTE was a commercial product (Teavigo) purchased from DSM NutritionProducts Ltd., Switzerland. It contains a minimum of 90% EGCG.
The formulation of diets was based on the AIN-93G recommendation . Thecontrol diet was the low-fat (LF) diet which contained corn oil (70 g/kg), casein(200 g/kg), corn starch (529.5 g/kg), mineral mix (35 g/kg) and vitamin mix (10 g/kg).The high-fat (HF) diet contained corn oil (70 g/kg), Crisco shortening (230 g/kg;Procter & Gamble, Cincinnati, OH, USA), casein (235 g/kg), corn starch (255.5 g/kg),mineral mix (42 g/kg) and vitamin mix (12 g/kg). In addition, all diets containedsucrose (100 g/kg), cellulose (50 g/kg) andmiscellaneous ingredients (2.5 g/kg cholinebitartrate, 3.0 g/kg L-cystine and 0.014 g/kg tert-butylhydroquinone). Green tea extractwas added to the HF diet at the expense of cornstarch. GT1 and GT2 diets contained,respectively, 7.5 g and 10 g GTE/kg. Energy density of the LF and HF diet was 16.5 and21.1 MJ/kg, respectively.
2.2. Animal experiments
All animal protocols were approved by the Committee on the Use of Live Animals inTeaching and Research at The University of Hong Kong (no. 1949-09). Virgin femaleSpragueDawley rats, at 4 weeks of age, andmale SpragueDawley rats (for mating), at7 weeks of age, were obtained from the animal unit of the Medicine Faculty. Rats werehoused individually and kept in a controlled environment at 22C under a 12-h-light/12-h-dark cycle with light on from 7:00 a.m. to 7:00 p.m. Water and laboratoryfood (Lab Diet, The Richmond Standard; PMI Nutritional International Inc., St. Louis,MO, USA) were available ad libitum to male rats at all time and female rats for a fewdays before they were assigned to their respective diet groups. Food intake and bodyweight were measured two to three times weekly.
The female rats (n=8 per group) were given LF, HF, GT1 or GT2 diet for 8 weeks.Tail blood was collected at the end of week 8. Starting at week 9, female rats and malerats (450500 g) were housed together. On the day that a copulation plug was found(referred to as G1 in Table 1), the pregnant female was separately housed and
Table 1Body weight, energy intake, energy efficiency and fat mass of dams1
LF HF GT1 GT2
Before matingBody weight (week 1), g 1166 1203 1193 1183Body weight (week 8), g 31110b 34510a 2958bc 2785c
Weight gain (week 18), g 19513b 2258a 1768bc 1604c
Energy intake (week 18), MJ 16.30.3ab 17.20.3a 15.60.4bc 15.00.5c
Energy efficiency (week 18),g gain/MJ consumed
11.90.6ab 13.10.3a 11.30.4bc 10.60.3c
GestationBody weight (G1), g 31912ab 3339a 2908b 28913b
Body weight (G15),2 g 41719 42716 37814 37919Weight gain (G115), g 9811 948 888 8910Energy intake (G121), MJ 8.30.7 9.50.4 9.40.3 8.30.3LactationBody weight (PPD1), g 38016ab 40817a 35414b 34614b
Weight change (PPD121), g 257bc 467c 128ab 47aEnergy intake (PPD121), MJ 17.11.2 14.41.3 15.20.7 14.40.9Visceral fat (PPD21), g 14.81.7ab 18.02.5a 11.22.1b 11.61.6b
1 Values are meansS.E.M., n=8. Means within a row lacking a common superscriptlettera,b,c,d differ (Pb.05).
2 To avoid disturbing the dams near parturition, body weight of dams was onlymeasured up to day 15 of gestation.remained on its original diet throughout gestation and lactation. At parturition, thepups were weighed, and litter size was standardized to eight per dam. At weaning[postpartum day (PPD) 21], male pups (with median body weight [BW]) were selectedfrom each litter and weaned to the HF, GT