an investigation on burn wound healing in rats with chitosan gel formulation containing epidermal...
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Burns 32 (2006) 319–327
An investigation on burn wound healing in rats with chitosan gel
formulation containing epidermal growth factor
Ceren Alemdaroglu a, Zelihagul Degim a,*, Nevin Celebi a, Fatih Zor b,Serdar Ozturk b, Deniz Erdogan c
a Department of Pharmaceutical Technology, Gazi University, Faculty of Pharmacy, 06330 Etiler, Ankara, Turkeyb Department of Plastic and Reconstructive Surgery, Gulhane Military Medical Academy, 06010 Etlik, Ankara, Turkey
c Department of Histology, Gazi University, Faculty of Medicine, 06300 Besevler, Ankara, Turkey
Abstract
Various studies have shown that chitosan is effective in promoting wound healing. In this study, we aimed to develop an effective chitosan
gel formulation containing epidermal growth factor (EGF), and to determine the effect on healing of second-degree burn wounds in rats. Ten
micrograms per millilitre EGF in 2% chitosan gel was prepared. In an in vitro study to investigate release of EGF from the formulations, the
release rate was 97.3% after 24 h. In in vivo studies, animals were divided into six groups as follows: silver sulfadiazine [Silverdin1 cream
(SIL)], chitosan gel with and without EGF (EJ, J), EGF solution (ES) and untreated control groups [unburned (S) and untreated (Y) rats]
applied groups, respectively. A uniform deep second-degree burn of the backskin was performed with water heated to 94 � 1 8C during a 15-s
exposure. The EGF formulations were repeatedly applied on the burned areas with a dose of 0.160 mg/cm2 for 14 days (one application per
day). Healing of the wounds was evaluated immunohistochemically, histochemically and histologically on the tissue samples. When the
results were evaluated immunohistochemically, there were significant increases in cell proliferation observed in the EGF containing gel
applied group ( p < 0.001). The histochemical results showed that the epithelization rate in the EJ group was the highest compared to the ES
group results ( p < 0.001). The histological results indicated and supported these findings. It can be concluded that a better and faster
epithelization was observed in the EJ group compared to the other groups.
# 2005 Elsevier Ltd and ISBI. All rights reserved.
Keywords: Epidermal growth factor; Chitosan; Burn; Wound healing
1. Introduction
Disruption of the skin generally leads to increased fluid
loss, infection, hypothermia, scarring, compromised immu-
nity and change in body image [1–3]. All these factors
together are very important; furthermore, large skin damage
can cause mortality. The mortality rate from burns has
declined in the past decade; however, it is still high if more
than 70% of the body surface is injured or burned [4].
Burns are classified according to the depth of the injury.
In superficial second-degree burns, the epidermis and the
superficial dermis are mainly affected. These kinds of burns
are very painful. The main causes of a superficial second-
degree burn are hot liquids [5].
* Corresponding author. Tel.: +90 312 212 21 07; fax: +90 312 212 79 58.
E-mail addresses: [email protected], [email protected] (Z. Degim).
0305-4179/$30.00 # 2005 Elsevier Ltd and ISBI. All rights reserved.
doi:10.1016/j.burns.2005.10.015
Wound healing is a complex process involving various
mechanisms, such as coagulation, inflammation, matrix
synthesis and deposition, angiogenesis, fibroplasia, epithe-
lization, contraction and remodeling. Growth factors are
polypeptides that control the growth, differentiation and
metabolism of cells and regulate the process of tissue repair
[6–9]. The fluids at wound sites may be an important reservoir
of growth factors that promote the wound healing process
[10]. Growth factors bind to specific high-affinity receptors
on the cell-surface to stimulate cell growth. Although they are
present in small amounts, they exert a powerful influence on
the process of wound repair [9]. There are some studies
reported dealing with growth factors in burn wound healing,
in which it is has been suggested that they may play an
important role in the healing process [11–13].
Several defined peptide growth factors, including
epidermal growth factor (EGF), platelet derived growth
C. Alemdaroglu et al. / Burns 32 (2006) 319–327320
factor (PDGF), fibroblast growth factor (FGF) and
transforming growth factor-beta (TGF-b), have been shown
to stimulate cellular proliferation and synthesis of the
extracellular matrix [6,14,15].
Chitosan is a polysaccharide comprising copolymers of
glucosamine and N-acetylglucosamine. It is derived by
partial deacetylation of chitin from crustacean shells [16].
Due to its high molecular weight of 50–2000 kDa, chitosan
exhibits a positive charge and film-forming and gelation
characteristics [17]. Previously published papers indicate
that chitosan enhances the functions of inflammatory cells
such as polymorphonuclear leukocytes, macrophages and
fibroblasts; thus, it promotes granulation and organization.
Therefore, chitosan can be used for large open wounds
[17,18].
In experimental animal models, chitosan was shown to
influence all stages of wound repair [19]. The hemostatic
activity of chitosan can be seen in the inflammatory phase. It
also interacts with and regulates the migration of neutrophils
and macrophages acting on repairing processes such as
fibroplasia and reepithelization [19,20]. During the inflam-
matory stage, chitosan accelerates the infiltration of
inflammatory cells such as neutrophils; therefore, the wound
area is cleaned from foreign agents. At the new tissue
formation period, formation of granulation tissue takes place
within the wound space. Simultaneously, fibroplasia begins.
Generally wide-open wounds become a hypertrophic scar,
due to the imbalance of type I and type III collagens.
However, as an advantage, open wounds in dogs and cats
which were treated with chitosan did not leave a wide scar
[7].
Chitosan gel also acts as an ideal wound dressing. It is
biocompatible, biodegradable, hemostatic, anti-infective
and, more importantly, it accelerates wound healing [20].
Chitosan gel has a strong tissue-adhesive property. A
previous study showed that chitosan-treated wounds were
epithelized when compared with wounds of the control
group after the treatment [20].
EGF is a small polypeptide of 53 amino acid residues and
has a molecular weight of 6216 Da [10]. EGF has been
reported to accelerate cellular proliferation and synthesis of
the extracellular matrix in numerous papers [9,10,21,22].
EGF acts by binding to the EGF receptor – tyrosine kinase –
thereby initiating a series of events which regulate cell
proliferation [23–25]. Recently, several formulations of EGF
have been studied regarding their ability to accelerate wound
healing. The most commonly used form is solution; there are
only a few studies reported dealing with bioadhesive gel,
microemulsion and liposome [9,10,21,22]. The commonly
used form is ointment formulations of EGF in burn wound
healing [12]. These results suggest that EGF formulations
may play an important role in wound healing after burns.
In vivo, several studies have proven that EGF is effective
for the acceleration of epithelization in human and animal
wounds [9,10,21,26]. EGF stimulates the proliferation of
keratinocytes in culture, and topical administration of EGF
accelerates dermal regeneration of partial thickness burns or
split-thickness incisions in vivo [27], but no study has been
done for the treatment of second-degree burn wounds with
EGF containing chitosan.
In light of the above, we aimed to develop a chitosan gel
formulation of EGF for the treatment of second-degree burn
wounds in rats. The results of the in vivo experiments were
evaluated immunohistochemically, histochemically and
histologically.
2. Materials and methods
2.1. Materials
Human epidermal growth factor (hEGF) was purchased
from Sigma, USA. Chitosan-H was kindly provided by
Dainichiseika Color & Chemicals Mfg. Co. Ltd., Japan.
Bromodeoxyuridine (BrdU) and anti-BrdU were purchased
from Sigma. Glacial acetic acid was supplied from Merck,
Germany. All other chemicals and solvents were of
analytical grade.
2.2. Methods
2.2.1. In vitro studies
2.2.1.1. Preparation of the chitosan gel. Glacial acetic
acid (0.5%) was added into half of the required water. The
weighed amount of chitosan was added and stirred slowly.
After the swelling, the remaining amount of water was
added and mixed. Gel was kept at room temperature
overnight before the application in order to remove the air
bubbles. The pH of the gel was measured as 5.32. After the
preparation of the chitosan gel, the required amount of EGF
solution was added and the final concentration was 10 mg/
mL. The molecular range of chitosan is 650,000 and
viscosity value of 2% chitosan solution is 7903 mPa at
25 8C.
2.2.1.2. In vitro release studies of EGF from the chitosan
gel formulation. An in vitro release study of EGF from the
chitosan gel formulation was also performed. The release
properties of EGF from the formulation were studied
according to the previously reported procedures [22].
Briefly, 1 mL of chitosan gel–EGF formulation with a
concentration of 2 mg/mL was placed in a dialysis sac
having a pore size of 12,000 Da, and the sac was immersed
in a constantly stirred receiver vessel containing a 15-fold
higher volume of the drug free phosphate buffer (pH 5.8) at
32 � 0.5 8C. At the designated periods, the sample (3 mL)
was removed from the receiver vessel and replenished with
fresh buffer. The samples were then analyzed using a
Shimadzu RF-1501 spectrofluorometer [28], and release
profile was observed. The excitation wavelengths were
342 nm with an emission wavelength of 260 run.
C. Alemdaroglu et al. / Burns 32 (2006) 319–327 321
Table 1
Design of experimental animal groups
Group codes Treatment
S Unburned
Y Burned but untreated
J Burned and treated by chitosan gel without EGF
EJ Burned and treated by chitosan gel with EGF
SIL Burned and treated by Silverdin1
ES Burned and treated by EGF solution
Fig. 1. In vitro release profile of EGF from chitosan–gel at pH 5.8
phosphate buffer at 32 � 0.5 8C (n = 6).
2.2.2. In vivo studies
2.2.2.1. Design of animal experiments. All animal experi-
ments were conducted under the protocols approved by the
Animal Care and Use Committee of Gulhane Military
Medical Academy. For the in vivo experiments, female
Sprague–Dawley rats weighing 250 � 10 g were used.
Rats were housed in individual cages with unrestricted
food and water access. The animals were divided into six
groups. The unburned group consisted of 4 rats and there
were 12 animals in each group. The design of the animal
groups is shown in Table 1.
2.2.2.2. Formation of the burn wounds. The trauma was
performed by exposing the shaved backskin of anesthetized
animals to hot water. For this procedure, a cylindrical shaped
bar with the radius of 1 cm was placed on the backs of rats
and then hot water (94 � 1 8C) was poured into this bar and
held for 15 s [29]. After the formation of standard, second-
degree burns wounds, the formulations were repeatedly
applied (one application every day) to the burned areas for
14 days. Full thickness skin biopsies were collected at the
3rd, 7th and 14th days after wound formation, and the degree
of healing was evaluated both immunohistochemically and
histochemically.
2.2.2.3. Immunohistochemical studies. For the evaluation
of the healing, bromodeoxyuridine technique was used.
BrdU is a pyrimidine analogue that is incorporated into
DNA-synthesizing nuclei. In immunohistochemical studies,
the BrdU incorporated into DNA has been detected using
antibodies against BrdU [30].
One hour before animals were sacrificed, BrdU (100 mg/
kg body weight) dissolved in saline was injected i.p. The
animals were then sacrificed and full thickness skin biopsies
were collected.
After all the steps of immunohistochemical staining had
been performed, the samples were assessed using Ks400
Vision Imaging Analysis Program under Zeiss Axioskop
light microscope. The values were represented as BrdU per
10 high power field (HPF).
2.2.2.4. Histochemical studies. The skin biopsies taken
from all groups were embedded in paraffin and the sections
were stained using hematoxylin and eosine and trichrome
staining techniques.
2.2.2.5. Measurement of epidermis thicknesses. Increment
in the epidermis thickness is one of the important indicators
of wound healing. Measurements were carried out using
Ks400 Vision Screening Analysis Program.
2.2.2.6. Measurement of fibroblast nucleus area. The area
of the fibroblast nuclei was measured using Ks400 Vision
Screening Analysis Program under Zeiss Axioskop light
microscope after trichrome staining. The increment in the
fibroblast nucleus sizes indicates a faster healing process.
Fifteen different areas from each preparation were examined.
2.2.2.7. Histological investigation. In order to compare the
effects on EJ, ES, SIL and J groups and untreated control
groups [unburned (S) and untreated (Y) rats] histologically,
structural changes in the skin layers were examined using
transmission electron microscope (TEM 911 Carl Zeiss).
Tissues were fixed in phosphate-buffered solution contain-
ing 2.5% glutaraldehyde for 2 h, then they were post-fixed in
1% osmium tetroxide (OsO4) and dehydrated in a series of
graded alcohols. After passing through propylene oxide, the
specimens were embedded in Araldyt CY212, 2-dodecen-1-
yl succinic anhydride (DDSA) and benzyldimethyl amine
(BDMA). Ultra-thin sections were stained with uranyl
acetate and lead citrate and examined with the electron
microscope.
2.2.2.8. Statistical analysis. All data are expressed as
means � S.D. Statistical analysis of data was performed
using one-way ANOVA.
3. Results
3.1. In vitro studies
3.1.1. In vitro release of EGF from the gel formulation
The release of EGF from the chitosan gel was found to be
97.3% to the pH 5.8 phosphate buffer during 24 h. The in
vitro release of EGF is shown in Fig. 1. The release kinetics
C. Alemdaroglu et al. / Burns 32 (2006) 319–327322
Table 2
The average stained cell number labeled with BrdU at various days of
treatment for the different groups
Groups The average stained cell number
labeled with BrdU (%) � S.D.
3rd day 7th day 14th day
S 2.11 � 0.12 2.10 � 0.10 2.13 � 0.15
Y –a 1.27 � 0.15 2.33 � 0.38
J 1.20 � 0.17 2.43 � 0.61 3.10 � 0.68
EJ 1.63 � 0.35 4.20 � 0.18 4.95 � 0.39
ES 1.43 � 0.28 4.25 � 0.13 3.90 � 0.64
SIL 1.48 � 0.29 3.27 � 0.15 4.53 � 0.53
a No healing.
Fig. 2. The average cell number labeled with BrdU at the: (a) 3rd day, (b)
7th day and (c) 14th day of the treatment for the different groups (%) (n = 6)
( p < 0.001).
Fig. 3. Stained proliferated cell (shown with arrows).
from the gel formulation were found to be the first order.
This result indicated that the release rate of EGF from the gel
varies with time.
3.2. In vivo studies
3.2.1. Evaluation of the immunohistochemical studies
Full thickness skin biopsies from the 3rd, 7th and 14th
days of therapy from all animal groups were examined
immunohistochemically using BrdU technique.
The average numbers of proliferating cells (%) labeled
with BrdU are shown in Table 2 and Fig. 2a–c at the 3rd, 7th
and 14th days, respectively. When the results were evaluated
immunohistochemically, the rate of healing in the EJ group
was found to be increased ( p < 0.001).
A sample image of the proliferated cell stained with BrdU
technique is shown in Fig. 3.
3.2.2. Evaluation of the histochemical studies
The full thickness skin samples of the untreated group,
the gel without EGF applied group, the EGF–gel formula-
tion applied group and the Silverdin1 (commercial silver
sulfadiazine cream) applied group were examined at the
14th day of the treatment after trichrome staining.
The epidermis thickness (Table 3; Fig. 4a–e) and
fibroblast nucleus areas (Fig. 5a–c) were also examined.
The histochemical findings of EJ and ES groups were found
to be similar.
Fibroblast nucleus areas in J, EJ, ES and control groups
were comparable at the 3rd day. The largest nucleus areas
were observed in EJ, ES and SIL groups at the 7th day. At the
14th day, the areas of the nucleus in the EJ group were
observed to have reached normal size (10.3 mm2 considering
S group) (Fig. 5a–c) ( p > 0.05). The results of the areas of
fibroblast nucleus are shown in Fig. 5a–c.
3.3. Histological studies
The wound tissues were investigated by ultra-thin
sectional preparation under a transmission electron micro-
scope at the 14th day of treatment. The results are
summarized as follows:
C. Alemdaroglu et al. / Burns 32 (2006) 319–327 323
Table 3
The 14th day epidermis thickness results according to group
Groups Average epidermis thickness (mm) � S.D.
S 6.03 � 0.09
Y –a
J –a
EJ 10.2 � 0.0
SIL 9.02 � 0.05
ES 11.5 � 0.4
a Ulcered tissue.
Fig. 4. The epidermis thickness of skin samples from different experimental groups: (a
(c) gel formulation without EGF applied group (J), (d) EGF–gel formulation applied
applied group (SIL), at the 14th day of treatment after trichrome staining (�5).
Healthy experimental group—S: Skin layers were clearly
identified, epidermis and dermis were observed to be
normal. A significant number of fibrils were also
observed (Fig. 6a).
Burn wound made but no treatment received group—Y:
Inflamed cells observed around the burn wound. Burned
cells were observed but detailed structure could not be
identified. Cell response was observed not to be proper at
deeper layer and epithelial tissues and collagen fibers
were irregular. Neutrophilic infiltrations were present at
) untreated group (Y), (b) EGF solution formulation applied group (ES),
group (EJ) and (e) Silverdin1 (commercial silver sulfadiazine cream)
C. Alemdaroglu et al. / Burns 32 (2006) 319–327324
Fig. 5. The areas of the fibroblast nucleus at the: (a) 3rd day (b) 7th day and
(c) 14th day of the treatment according to group ( p > 0.05).
Fig. 6. The microscopic image of the epidermis and dermis from the different experime
the treatment. E: epidermis; D: dermis (�3000).
the dermal surface and early development of scar tissue
was observed. The healing process was found to be
started after 14th day (Fig. 6b).
Burn wound made and a gel formulation without EGF
applied group—J: continuation of fibroblastic activity
was observed. Although no differentiation of epithelial
basal cell was observed, some degeneration of mitochon-
dria and loss of crista were noted. There was some wound
healing, indicated by active fibroblasts observed at
dermis (Fig. 7a).
Burn wound made and EGF containing gel applied
group—EJ: Emphasized epidermis layers and swollen
cells were observed under the wound scar. Some
vacuolization of the dermal cells and healing were
observed. An infiltration of inflamed cells was noticed.
The structures of surface epithelial cells were normal, but
some active fibroblasts and inflamed cells were present at
connective tissue layer. The microscopic image of the
EGF–gel formulation applied group at the 14th day of the
treatment is shown in Fig. 7b.
Burn wound made and EGF solution applied group—ES:
Although the epidermis could not be observed under the
wound scab, some inflammatory cells were found.
Infiltrations were observed; irregular myofibroblast
distributions, collagen fibers and many fibroblasts were
present. The continuation of fibroblastic activity, wound
scab and invasive niflammatory cell infiltrations under-
neath were also noticed. A degeneration of cells at
epithelial surface was seen, but some myofibroblasts,
accepted as one of the indications of wound healing, were
observed at dermis. The image of the EGF solution
applied group at the 14th day of the treatment is shown in
Fig. 7c.
ntal groups: (a) healthy group and (b) untreated group, at the 14th day of
C. Alemdaroglu et al. / Burns 32 (2006) 319–327 325
Fig. 7. The microscopic image of the epidermis and dermis from the different experimental groups: (a) gel formulation without EGF applied group, (b) EGF–
gel formulation applied group, (c) EGF solution applied group and (d) Silverdin1 (commercial silver sulfadiazine cream) applied group, at the 14th day of the
treatment. E: epidermis; Mf: myofibroblast; F: fibroblast (�3000).
Burn wound made and commercial Silverdin1 cream
applied group—SIL: Inflammatory cell infiltrations were
observed. At intercellular space of enlarged epidermis
cells and irregular formations at dermis were noticed.
Random distributions of myofibroblasts were present.
There were also some vacuoles; the healing process of the
wound was not completed. Epithelization was found to be
higher than in J and Y groups, but wound scab was still
present. The image of Silverdin1 (commercial silver
sulfadiazine cream) applied group at the 14th day of the
treatment is shown in Fig. 7d.
4. Discussion
Healing of skin wounds is quite a complicated process
involving epidermal regeneration, fibroblast proliferation,
neovascularization and synthesis. Although there have been
some advances, the best treatment remains undecided. Many
investigators have studied acceleration and whether the
duration of wound healing could be shortened. Some studies
have shown that exogenous application of growth factors
may decrease the healing period in burns [13,31].
Brown and colleagues [9] found that application of
epidermal growth factor accelerated healing in burns and
shortened the time and improved the quality of healing.
However, efficient delivery of the growth factor must be
considered. Trials have included liquids, gels and collagen
sponges as delivery vehicles for the growth factor. Chitosan
was proposed and used in burn wounds as a polymer for
delivery in this study. Chitosan is a biodegradable polymer
and it accelerates wound healing [32,33]. It has been
reported that chitosan permits regeneration of tissue
elements in skin wounds and has positive application
effects on wound healing [34]. Also, chitosan exhibits many
advantages for topical application, including good flow
properties, non-irritancy, some antibacterial effect and a
potential for a suitable release rate from the dosage form
[34]. It was shown in this study that treatment with EGF–
chitosan gel formulation decreased the wound healing
period, accelerated epidermal regeneration and stimulated
granulation; tissue formation could be obtained.
C. Alemdaroglu et al. / Burns 32 (2006) 319–327326
Monteglione et al. determined the tertiary structure of
murine EGF at pH 3.1 and a temperature of 28 8C using
NMR analysis and distance geometry calculations and
restrained energy minimization [35]. The molecular
architecture of murine EGF was found to be as same as
that described previously. Kohda et al. have done similar
experiments and the tertiary structure of mouse epidermal
growth factor in solution (28 8C, at pH 2.0) was studied by
two-dimensional NMR spectroscopy. The chain folds in the
two structural domains of mouse EGF and again the
structure was found to be very similar to those previously
reported ones [35]. The tertiary structure of the EGF was
found to be similar to other reported structures in acidic
medium [36]. The isoelectric point of the EGF was 4.5 [37].
According to the report of Medved et al., the stability of the
EGF was found to be decreased if the pH of the solution is
below than 3.8 [38]. Both epidermal growth factor and
transforming growth factor bind to EGF receptors and TGF
has been reported to be more potent than EGF as far as many
biological effects are concerned. One possible reason for this
is thought to be the difference in their dissociation from the
receptors in intracellular acidic compartments, which may
affect the final pathway (lysosomal degradation or recycling
to cell-surface) of endocytosed ligands [38]. According to
the report of Meada et al., there are some experiments that
have been performed to clarify the relationship between
intracellular dissociation from the receptors and the fate of
the endocytosed ligands. In these experiments, the
magnitude of the dissociation rate constants were deter-
mined for each ligand at pH 6.0, which is reported to be
similar to that inside early endosomes. pH 6.0 was reported
as a suitable pH for experiments with EGF considering the
stability in the solution, intracellular ligand/receptor
interaction and a dissociation reported as a minimal effect
on the affinity to the receptors on the cell-surface [39]. After
consideration of all these, pH 5.8 was chosen as a suitable
medium for in vitro EGF release experiments.
According to the in vitro release studies, the release of
EGF from the chitosan gel was found to be 97.3% after 24 h.
The release kinetics from the gel formulation were found to
be of the first order, and the release rate of EGF from the gel
varied with time. The burst effect or faster release was
observed from the gel at the initial period, after which EGF
was released for a longer time period at a lower rate; the
occlusive effect was also observed.
After the formation of second-degree burn wounds, the
EGF formulations were repeatedly applied on the burned
areas at a dose of 0.160 mg/cm2 for 14 days (one application
per day). Skin biopsies were collected at the 3rd, 7th and
14th days after the wound formation and the degree of
healing was evaluated histologically, immunohistochemi-
cally and histochemically.
When the results were evaluated immunohistochemically
at the 7th day of the therapy, the maximum cell proliferation
was found in the EJ group. The healing in the EJ and ES
groups was also found to be rather good, and it was seen that
the healing ratios were very similar ( p > 0.05). It was also
observed that the cell proliferation in J and other control
groups (S and Y groups) was extremely low. There were
significant increases in cell proliferation observed in the EGF
containing gel applied group ( p < 0.001). At the 14th day of
the therapy, the healing in the EJ and ES groups was noted as
being faster than that of other groups. When EJ, ES and SIL
groups were compared, the healing and the rate of healing in
the EJ group were found to be increased ( p < 0.001).
The histochemical results showed that the increase in the
epidermis thickness in the EJ group was the highest (Fig. 4a–
e). This observation indicates that the maximum healing
effect was in the EJ group. An increment in the diameter of
the fibroblasts is one of the indications of accelerated wound
healing. The areas of the fibroblast cell nucleus were also
measured in this study (Fig. 5a–c). The area of the cell
nucleus is related to the diameter of the fibroblast cells.
Therefore, the area of the cell nucleus was used for
comparison and conclusion. When the fibroblast nuclei areas
were evaluated at the 7th day, the healing rates in the ES and
EJ groups were similar, and the healing rate in the EJ group
was found to be the fastest. At the 14th day, the healing in the
EJ group was found to be the fastest compared with the ES
and SIL groups results.
Although an effect on the fibroblastic cells was observed
with the use of commercially available Silverdin1 ointment,
it can be used for a small burn wound [40]. Therefore, silver
sulfadiazine containing preparation may be useful for small
burn wounds.
The histological results indicated and supported that the
healing in the EJ group was better and more rapid when
compared with the other groups.
In conclusion, when the results were evaluated, it was
determined that EGF-containing formulations are effective
in the wound healing process. Growth factor formulations,
which play an important role in burn wound treatment, are
found to be promising for use in humans.
Acknowledgements
This study was supported by a research grant from Gazi
University (SBE-11/2002-14). The authors are grateful to
Assoc. Prof. Dr. Mustafa Deveci and Prof. Dr. Mustafa
Sengezer for providing the facilities for the in vivo
experiments; to Dr. Ahmet Nacar and Prof. Dr. Candan
Ozogul for their kind help in histological analysis; to Dr.
Melih Alomeroglu for analyzing the samples for the
immunohistochemical and histochemical studies.
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