Role of adipose-derived stromal cells in pedicle skin flap survival in experimental animal models

The use of skin flaps in reconstructive surgery is the first-line surgical treatment for the reconstruction of skin defects and is essentially considered the starting point of plastic surgery. Despite their excellent usability, their application includes general surgical risks or possible complications, the primary and most common is necrosis of the flap. To improve flap survival, researchers have used different methods, including the use of adipose-derived stem cells, with significant positive results. In our research we will report the use of adipose-derived stem cells in pedicle skin flap survival based on current literature on various experimental models in animals.

Successful management of an equine carpal chip fracture by intra-articularly injected adipose-derived stromal vascular fraction after arthroscopic removal

Carpal chip fractures are common causes of lameness in racehorses. Due to disadvantages in surgical management, adjuvant treatment modalities are usually necessary. Adipose-derived stem cells (ADSCs) have the potential to differentiate into other cell types including bone and cartilage cells. Adipose-derived stromal vascular fraction (SVF) is produced during ADSCs isolation from adipose tissue. The purpose of this report was to present the successful management of a grade III chip fracture in the right carpus of a 5-year-old Thoroughbred gelding by intra-articularly injected autologous SVF one month after the arthroscopic removal of the fracture. This treatment resulted in lameness improvement and short rehabilitation period to previous racing activities. High performance levels and no recurrent injuries were recorded during a twenty month follow-up period.

Stem cell models of polyglutamine diseases and their use in cell-based therapies

Polyglutamine diseases are fatal neurological disorders that affect the central nervous system. They are caused by mutations in disease genes that contain CAG trinucleotide expansions in their coding regions. These mutations are translated into expanded glutamine chains in pathological proteins. Mutant proteins induce cytotoxicity, form intranuclear aggregates and cause neuronal cell death in specific brain regions. At the moment there is no cure for these diseases and only symptomatic treatments are available. Here, we discuss novel therapeutic approaches that aim in neuronal cell replacement using induced pluripotent or adult stem cells. Additionally, we present the beneficial effect of genetically engineered mesenchymal stem cells and their use as disease models or RNAi/gene delivery vehicles. In combination with their paracrine and cell-trophic properties, such cells may prove useful for the development of novel therapies against polyglutamine diseases.

Mobilization of circulating progenitor cells following brain injury in premature neonates could be indicative of an endogenous repair process. A pilot study

BACKGROUND

Preclinical data and adult studies have showed an endogenous regeneration process following brain damage that involves mobilization of progenitor cells. This process is not well described in preterm neonates. The present study aims to investigate the mobilization of Circulating Progenitor Cells (CPCs) and their relation to biomarkers of brain injury in preterm neonates.

METHODS

This is a prospective cohort study of preterm infants with gestational age (GA) <34 weeks. Serial cranial ultrasounds scans were performed in all neonates. Brain injury was defined by the presence of intraventricular hemorrhage grade III/IV, cystic periventricular leukomalacia or infarct. Peripheral blood samples were collected from all neonates on days(d) 1, 3, 9, 18 and 45 of life for the measurement of levels of CPCs [early and late Endothelial Progenitor Cells (EPCs), Haematopoietic Stem Cells (HSCs) and Very Small Embryonic-Like Stem Cells (VSELs)], Neuron-Specific Enolase (NSE), S100b, Erythropoietin (EPO) and Stromal Cell-Derived Factor-1 (SDF-1) .

RESULTS

Ten out of the 23 preterm infants included in the study developed brain injury; the remaining thirteen infants served as controls. In the brain injury group a significant increase of HSCs (d9, d45), early EPCs (d3, d9, d18) and late EPCs (d1, d3, d9, d18, d45) was observed compared to controls. VSELs on d45 were significantly higher in controls. S100b on d1, EPO on d1, SDF-1 on d3 and NSE on d18 were significantly increased in the brain injury group. Moreover, CPCs were significantly related to S100b, NSE, EPO and SDF-1 levels at multiple time points.

CONCLUSIONS

The observed pattern of CPCs mobilization and its association with biomarkers following brain injury in preterm neonates indicate the existence of an endogenous brain regeneration process. Enhancement of this process with exogenous progenitor cell transplantation might be a powerful therapeutic strategy to restore brain damage and improve the neurodevelopmental outcome in premature infants. Hippokratia 2015; 19 (2):141-147.

Morning and night gastric emptying half-time differed more than 220% in two young healthy adults

OBJECTIVE

It is important to know normal GEHT of a specific meal taken at specific hours and at specific physical and biological conditions in order to better evaluate abnormal GEHT. It seems that it is more specific to study as we have done in the present paper GEHT in the same individual of a certain meal administered at two different hours, i.e. in the morning and at night. Thus, we avoided many errors and issues.

SUBJECTS AND METHODS

We studied 2 healthy individuals, one male 26 years old and one female, 19 years old, who received the same French toast meal at 08.00 and 23.00.

RESULTS

The GEHT for the morning and the night test for the male individual (P.F.) were 55min and 125min, respectively. For the female individual (K. F.) the GEHT were ∼70min and ∼120min, respectively. For both individuals GEHT differed more than 220% between the morning and night tests.

CONCLUSION

We noticed a more than 220% delay of the GEHT in a normal young man and a normal young woman when they received a French toast meal at 23.00h as compared to the same meal at 08.00h. The female had 58% more delayed in GEHT at night as compared to the GEHT of the male individual.

A simple method for the quantitation of the stem cells derived from human exfoliated deciduous teeth using a luminescent cell viability assay

Stem cells from human exfoliated deciduous teeth are a population of highly proliferative postnatal stem cells and have been characterized as multipotent stem cells. In this study we developed a fast and sensitive method for stem cells derived from human exfoliated deciduous teeth count, using a luminescent viability assay. We isolated stem cells from normal exfoliated deciduous teeth using collagenase/dispase digestions solutions. Separated stem cells were placed in opaque-walled multiwall plates in culture alpha Modified Eagle's Medium. For dental pulp stem cells quantitation we used a simple method for determining the number of viable cells based on ATP concentration. Cells attached to the bottom of the multiwall plates were counted with the luminescent assay and were cultured for mesenchymal markers expression. Moreover cells attached to the bottom of the multiwall plates were directed toward the osteogenic, adipogenic, lineages at the respective passages. Flow cytometry was used for immunophenotyping of cultured dental stem cells from exfoliated deciduous teeth. Cells that were counted with the luminescent assay, after culture formed fibroblastic morphology and were expressed the mesenchymal stem cell markers CD29, CD105, CD146, CD44. There was a correlation between the number of cells plated for culture and the number of mesenchymal stem cells after culture. Osteogenic and adipogenic differentiation of the cells counted with the luminescent assay was performed. The luminescent signal of viable mesenchymal dental stem cells isolated from dental pulp of exfoliated teeth represents an ideal method for mesenchymal stem cells count before culturing.

Lateral Traumatic Esophago-Cutaneous fistula in a Child; Platelet-Rich Fibrin Glue Challenge

Introduction

The endoscopic fibrin glue or platelet-rich fibrin glue (PRFG) injection is an easy, safe and effective technique for the fistula. So far, the use of fibrin glue has been limited to selected cases.

Case report

Our case is a three years old male child with a neck trauma resulting in a Esophago-Cutaneous fistula after a 3 month period of follow up we decided to use PRFG for this lesion after fine debridement of the fistula tract, and the surrounding fibrosed tissue twice with a one week interval. Our visit after two weeks showed complete recovery and normal general condition. A contrast study revealed complete disappearance of the lesion.

Conclusions

In our case the PRFG completely resolved a long-standing fistula resistant to exhaustive conservative management. The treatment with PRFG has been proved to be effective in the selected cases and it seems that traumatic esophago-cutaneous fistula may be one of these selections. Application of fibrin sealant should be considered early in the management of these difficult clinical problems.

Angiotensin-II-dependent NHE1 activation in human monocytes

Angiotensin II, a potent vasoconstrictor, has been demonstrated to be involved in the pathogenesis of atherosclerosis, and its complications. Na(+)/H(+) exchanger isoform-1 (NHE1) is related to hypertension activation and can augment atherosclerosis-related functions in human monocytes. The purpose of this study is to investigate in monocytes the signal transduction pathway induced by angiotensin II, in which the Na(+)/H(+) exchanger (NHE1) takes part. Monocytes were isolated, and intracellular pH (pHi) was measured by the use of Bis-(carboxyethyl)-5(6)-carboxy-fluorescein acetoxymethylester. Superoxide anions were measured by nitroblue tetrazolium. Monocyte binding to laminin-1 was quantified using the myeloperoxidase assay. Angiotensin II caused a significant increase in pHi of monocytes, which indicates NHE activation. Cariporide, an NHE1 inhibitor, GF109203X, and Gö6976, inhibitors of isoforms of protein kinase C (PKC), diphenyleneiodonium chloride, the inhibitor of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, and N(omega)-Nitro-L-arginine methyl ester hydrochloride, the inhibitor of nitric oxide (NO) synthase, reversed this effect. Moreover, it was shown that angiotensin II caused an increase in superoxide ion (O(2)(-.)) levels as well as an increase in monocytes' adhesion to laminin-1, in relation to controls. The use of cariporide inhibited these effects. Furthermore, angiotensin II caused an increase in pHi, which was reversed by cariporide in monocytes derived from hypertensive patients. Consequently, in human monocytes angiotensin II caused NHE1 activation through pathways involving isoforms of PKC with the participation of O(2)(-.) and NO. In addition, a link between angiotensin II and the atherogenic properties of monocytes was shown, where NHE1 plays a central role.

Intramyocardial implantation of autologous bone marrow-derived stem cells combined with coronary artery bypass grafting in patients with ischemic cardiomyopathy: a pilot study

BACKGROUND

Ischemic cardiomyopathy has the distinctiveness of irreversible myocardial damage with scar tissue formation and mainly impaired perfusion of the remaining viable myocardium. We present results of the first series of patients with severe ischemic cardiomyopathy managed in our institution with intramyocardial implantation of autologous bone marrow stem cells at the time of coronary artery bypass grafting. The aim is to evaluate feasibility and safety of the procedure in our institution.

PATIENTS AND METHODS

Nine patients with severe ischemic cardiomyopathy scheduled for elective coronary artery bypass grafting were managed with concurrent intramyocardial autologous bone marrow stem cells injection in pre-defined viable peri-infarct areas that showed poor perfusion and could not be grafted. Detailed mapping of infracted and hibernating myocardial segments was performed in all patients with single photon emission computed tomography segmental analysis.

RESULTS

There was no perioperative 30-day mortality. Improvement was evident in left ventricular ejection fraction which was increased significantly from 31.3% preoperatively to 42.4%, 46.6% and 52.5% at 3, 6 and 12 months respectively. Postoperative thallium scintigraphy revealed increased perfusion in myocardial segments corresponding to areas of stem cell injection and a net reduction in the estimated infarct size at 6 and 12 months in 5/8 (62.5%) patients.

CONCLUSIONS

Preliminary data from this pilot study show that intramyocardial administration of bone marrow stem cells in patients undergoing coronary bypass grafting for ischemic cardiomyopathy is safe and associated with an improvement in left ventricular function and enhanced reperfusion of non-viable myocardial territories.

The effects of iloprost on colonic anastomotic healing in rats

PURPOSE

The purpose of this experimental study is to investigate the effects of iloprost on colonic anastomotic healing in rats, after intraperitoneal administration.

METHODS

Forty male Albino-Wistar rats were randomized into two groups of twenty animals each. They all underwent colonic resection followed by an inverted anastomosis. The rats of Group A (control) received 3 ml of NaCl intraperitoneally, while those of Group B (iloprost) received iloprost (2 μg/kg body weight), immediately postoperatively and daily until killed. Each group was further divided into two equal subgroups, depending on the day of killing. The animals of subgroups 1 were killed on the fourth postoperative day, while those of subgroups 2 on the eighth. Macroscopical and histological assessments were performed. Besides, anastomotic bursting pressures and the tissue concentrations in hydroxyproline and collagenase I were also evaluated.

RESULTS

No anastomotic dehiscence was noted. The mean bursting pressure was higher in the iloprost group compared with the control group, but a significant difference was revealed only on the fourth postoperative day. Furthermore, iloprost significantly increased the new vessel formation on the fourth, as well as on the eighth postoperative day.

CONCLUSION

Iloprost enhances the early phase of colonic anastomotic healing in rats.

The effects of the intraperitoneal administration of oxaliplatin and 5-FU on the healing of colonic anastomoses: an experimental study

BACKGROUND

The purpose of this experimental study was to assess the effects of the immediate postoperative intraperitoneal administration of oxaliplatin and 5-FU on the healing of colonic anastomoses in rats.

METHODS

Sixty rats were randomized into 4 groups of 15 rats each and were subjected to colonic anastomoses. To the 1st group, saline solution was administered immediately postoperatively, intraperitoneally. To the 2nd group, 5-FU was administered, to the 3rd group oxaliplatin and to the 4th group 5-FU and oxaliplatin were administered immediately postoperatively, intraperitoneally. After killing the rats on the 8th postoperative day, the anastomoses were examined macroscopically and the anastomotic bursting pressures were measured. The anastomoses were also examined histologically and the hydroxyproline contents were determined.

RESULTS

Rupture of the anastomosis was observed in no rats of the 1st group, in 3 rats of the 2nd group, in 4 rats of the 3rd group and in 7 rats of the 4th group (P = 0.016). The bursting pressure (P < 0.001), the hydroxyproline content (P < 0.001) and the concentration of collagen (P < 0.001) and fibroblasts (P < 0.001) were significantly lower in the 2nd, 3rd and 4th group in comparison with the 1st group. The formation of adhesions and the leukocytosis on the anastomoses were significantly higher in the 2nd, 3rd and 4th group than in the 1st group (P < 0.001).

CONCLUSIONS

The immediate postoperative, intraperitoneal administration of oxaliplatin, 5-FU or the combination of 5-FU and oxaliplatin impairs the healing of colonic anastomoses in rats.

Intraperitoneally administered irinotecan with 5-fluorouracil impair wound healing of colonic anastomoses in a rat model: an experimental study

AIM

The aim of this experimental study is the assessment of the effects of the immediate post-operative intraperitoneal administration of 5-fluorouracil and irinotecan on the healing process of large bowel anastomoses in rats.

MATERIALS AND METHODS

Sixty male Wistar rats were divided into 4 groups of 15 rats each. The rats underwent large bowel resection and anastomosis, followed by the intraperitoneal administration of normal saline (group 1), 5-fluorouracil (group 2), irinotecan (group 3) or the combination of 5-fluorouracil and irinotecan (group 4). All animals were killed on the eighth post-operative day. During post-mortem examination, the anastomoses were assessed macroscopically for a possible anastomotic leak and the extent of adhesion formation. Subsequently, the anastomotic bursting pressure was measured, and the anastomoses were assessed histologically.

RESULTS

No anastomotic dehiscence was observed in the rats of group 1. In groups 2 and 3, we observed 3 anastomotic leaks in each group, and in group 4, we observed 5 leaks (P = 0.111). The mean bursting pressure of the anastomoses in group 1 was significantly higher compared to groups 2, 3 and 4 (P < 0.001). The least inflammatory cell infiltration score was observed in group 1 (P < 0.001). The lowest neoangiogenesis score was observed in group 2 and the highest in group 4. The collagen formation in group 1 was significantly higher compared to the other 3 groups (P < 0.001). Similar results were observed for the fibroblast activity, where group 1 revealed significantly higher fibroblast scores compared to groups 2, 3 and 4 (P < 0.001). Finally, groups 2, 3 and 4 showed significantly lower hydroxyproline levels compared to the control group (P < 0.001).

CONCLUSION

The immediate, post-operative intraperitoneal administration of 5-fluorouracil or irinotecan had a negative effect on the healing process of the large bowel anastomoses in rats. The negative effects of the combination of 5-fluorouracil and irinotecan were statistically more significant compared to the single use of 5-fluorouracil or irinotecan.

The effects of tacrolimus on colonic anastomotic healing in rats

AIM

The aim of this experimental study is to investigate the effects of tacrolimus on colonic anastomotic healing after subcutaneous administration.

MATERIALS AND METHODS

Forty Albino-Wistar male rats were divided into two groups, with two equal subgroups each. They all underwent colonic resection followed by a single-layer, inverted colon anastomosis and were injected subcutaneously with either 1 ml of 0.9% NaCl solution or tacrolimus (0.1 mg/kg body weight) depending on their group. Half of the rats were sacrificed on the fourth postoperative day, while the remaining half were sacrificed on the eighth postoperative day. Macroscopical and histological assessment was performed, while anastomotic bursting pressures and the tissue concentrations in hydroxyproline and collagenase I were evaluated.

RESULTS

On the fourth postoperative day, the bursting pressures (217.00 ± 11.12, p < 0.001), the fibroblast activity (2.80 ± 0.42, p = 0.022), the neoangiogenesis (2.10 ± 0.32, p = 0.007) and the tissue hydroxyproline concentration (254.23 ± 67.10, p = 0.001) were significantly higher in the tacrolimus-treated animals. Furthermore, tacrolimus significantly decreased the inflammatory cell infiltration (1.50 ± 0.53, p < 0.001) and the tissue collagenase I concentration (4.16 ± 0.76, p = 0.002). On the eighth day, the bursting pressure (264.00 ± 32.61, p < 0.001) and the hydroxyproline tissue concentration (331.04 ± 55.56, p = 0.002) were significantly higher in the tacrolimus subgroups. The inflammatory cell infiltration (1.20 ± 0.42, p < 0.001) and the collagenase I concentration (1.61 ± 0.83, p < 0.001) were significantly lower. In addition, the adhesion formation score was significantly lower (1.20 ± 0.92, p = 0.065).

CONCLUSION

Tacrolimus, when injected subcutaneously, promotes healing of colonic anastomoses in rats. It impairs not only inflammatory response but also collagen degradation, resulting to increased anastomotic strength on the fourth as well as on the eighth postoperative day.

Stem cell therapy for idiopathic pulmonary fibrosis: a protocol proposal

Background

Idiopathic pulmonary fibrosis represents a lethal form of progressive fibrotic lung disorder with gradually increasing incidence worldwide. Despite intense research efforts its pathogenesis is still elusive and controversial reflecting in the current disappointing status regarding its treatment. Patients and Methods: We report the first protocol proposal of a prospective, unicentric, non-randomized, phase Ib clinical trial to study the safety and tolerability of the adipose-derived stem cells (ADSCs) stromal vascular fraction (SVF) as a therapeutic agent in IPF. After careful patient selection based on functional criteria (forced vital capacity-FVC > 50%, diffuse lung capacity for carbon monoxide-DL_CO > 35% of the predicted values) all eligible subjects will be subjected to lipoaspiration resulting in the isolation of approximately 100- 500 gr of adipose tissue. After preparation, isolation and labelling ADSCs-SVF will be endobronchially infused to both lower lobes of the fibrotic lungs. Procedure will be repeated thrice at monthly intervals. Primary end-point represent safety and tolerability data, while exploratory secondary end-points include assessment of clinical functional and radiological status. Results: Preliminary results recently presented in the form of an abstract seem promising and tantalizing since there were no cases of clinically significant allergic reactions, infections, disease acute exacerbations or ectopic tissue formation. In addition 6 months follow-up data revealed a marginal improvement at 6-minute walking distance and forced vital capacity.

Conclusions

Adipose tissue represents an abundant, safe, ethically uncontested and potentially beneficial source of stem cells for patients with IPF. Larger multicenter phase II and III placebo-controlled clinical trials are sorely needed in order to prove efficacy. However, pilot safety studies are of major importance and represent the first hamper that should be overcome to establish a rigid basis for larger clinical trials.

Plasma neuropeptide Y (NPY) and alpha-melanocyte stimulating hormone (a-MSH) levels in patients with or without hypertension and/or obesity: a pilot study

AIM

Obesity frequently co-exists with hypertension (HTN). Hypothalamus neuropeptides such as neuropeptide Y (NPY) and alpha-melanocyte stimulating hormone (a-MSH) interact with leptin, an anorexic peptide produced mainly by adipose tissue and are involved in the regulation of appetite, energy balance and sympathetic nervous system (SNS) activity, possibly contributing to blood pressure (BP) elevation. We compared plasma NPY and a-MSH levels between patients with or without hypertension and/or obesity and the differences in these neuropeptides between patients with or without pathological heart echo findings, aiming to investigate the possible role of these peptides in obesity induced HTN.

PATIENTS AND METHODS

160 non-diabetic, treatment-naïve individuals were randomly recruited from our outpatient clinics. Study population was divided into 6 groups, according to body mass index-BMI (OB=obese, OW=overweight, NW=normal weight) and blood pressure. Waist circumference (WC) and heart rate (HR) were also recorded. A heart echo was performed and plasma NPY and a-MSH levels were measured for all participants.

RESULTS

Plasma NPY levels and HR were higher in OW and OB hypertensives compared with NW hypertensives. OW and OB hypertensives had also higher NPY concentrations compared with OW and OB normotensives, respectively. However, in NW patients, plasma NPY concentrations did not differ between hypertensives and normotensives. Patients with central obesity (COB) had also higher NPY levels compared with patients without COB, a difference also observed in hypertensives but not in normotensive patients. Furthermore, plasma NPY concentrations were significantly correlated with BMI, WC, HR, systolic and diastolic BP. Patients with left ventricle hypertrophy had higher plasma NPY levels compared with those with normal findings, but this was not seen in hypertensives. The majority of these differences were also observed in male and female patient populations. In contrast, plasma a-MSH levels were similar in all study groups.

CONCLUSIONS

These results suggest that NPY may be involved in obesity-related HTN, possibly via increased SNS activity. Further investigation is needed to elucidate the role of both NPY and a-MSH in obesity-related HTN.

NHE-1 and β1 integrin dependent monocyte adhesion and migration after glucose, insulin or PPARγ stimulation

In the present study the effect of high glucose concentrations, insulin, PPARγ activators (rosiglitazone) and NHE-1 inhibitors (cariporide) in atherosclerosis-related functions of human monocytes was investigated. Monocyte adhesion to laminin-1, collagen type IV and endothelial cells, as well as monocyte migration through the same substrates were studied. Incubation of the monocyte suspension with high glucose concentrations, insulin and rosiglitazone induced all the studied atherosclerosis-related functions of the monocytes. In all these functions the addition of cariporide counteracted the activity of glucose, insulin and rosiglitazone. The use of antigen for β1 integrin also counteracted the activity of the above in monocyte adhesion in all three substrates. The data of the present study suggests that PPARγ activation in monocytes induces atherosclerosis, and that NHE-1 and β1 integrin play an important role in the beginning of atherosclerosis.

Treatment of non-healing wounds with autologous bone marrow cells, platelets, fibrin glue and collagen matrix

BACKGROUND AIMS

Recalcitrant diabetic wounds are not responsive to the most common treatments. Bone marrow-derived stem cell transplantation is used for the healing of chronic lower extremity wounds.

METHODS

We report on the treatment of eight patients with aggressive, refractory diabetic wounds. The marrow-derived cells were injected/applied topically into the wound along with platelets, fibrin glue and bone marrow-impregnated collagen matrix.

RESULTS

Four weeks after treatment, the wound was completely closed in three patients and significantly reduced in the remaining five patients.

CONCLUSIONS

Our study suggests that the combination of the components mentioned can be used safely in order to synergize the effect of chronic wound healing.

Intraperitoneal administration of bevacizumab intraoperatively does not affect abdominal wound healing in rats

BACKGROUND

Bevacizumab is a monoclonal antibody targeted at vascular endothelial growth factor (VEGF) to treat advanced colorectal cancer as well as other malignancies, but the ideal time point for its administration in patients scheduled for surgery is not well defined due to serious concerns regarding possible side effects on wound healing. Therefore, we conducted an experimental study in rats to clarify this issue.

METHODS

Four groups of 10 Wistar rats each underwent a 4-cm midline laparotomy and closure of the wound in 2 layers. In the treatment groups (A and B), bevacizumab (Avastin(®)) received a single dose of 5 mg/kg i.p., and an equal amount of saline was given to the control groups (C and D). Groups A and C were sacrificed on the 7th postoperative day, and groups B and D on the 14th postoperative day. Wounds were inspected by two independent observers upon sacrifice and results were recorded; wound tissues were sent for histology to assess the degree of fibrosis and measurement of tissue hydroxyproline levels. Serum levels of endothelin-1, C-reactive protein, pro-oxidant/antioxidant balance and carbonylated proteins were also determined. For statistical analysis, the Mann-Whitney U test was used.

RESULTS

Wound healing did not differ among groups both on the 7th and the 14th postoperative days, and there was also no significant difference regarding the degree of inflammation, fibroblast proliferation and collagen synthesis, as well as hydroxyproline and biochemical marker levels among the groups.

CONCLUSIONS

Intraperitoneal bevacizumab administered intraoperatively does not significantly affect abdominal wound healing in rats.