Nurten Renda

Effects of Polyglycolic Acid and Polypropylene Meshes on Postoperative Adhesion Formation in Mice

Abstract The purpose of this study was to investigate the effects of polyglycolic acid (PGA), an absorbable (ABS) mesh, and polypropylene (PP), a nonabsorbable (NA) mesh, on intestinal adhesion formation. Altogether 72 mice were divided into a control group of 24, an ABS mesh group of 23, and an NA mesh group of 25. All three groups were divided into two subgroups for evaluation of adhesion severity at postoperative (po) days 5 and 90. Adhesion severity was measured with adhesion grading and tissue hydroxyproline (OHP) levels. Adhesion degree was minimal (1) in all subjects on day 5. Also there was no difference in tissue OHP levels between three groups on day 5 ( p > 0.05). Adhesion degree and tissue OHP levels as determinants of adhesion severity were higher in the PGA mesh group than the control group and the PP mesh group on day 90 (p < 0.001). There was no difference between the control group and the PP mesh groups (p > 0.05). Adhesion degree was higher on day 90 than on day 5 in the control group and the PGA mesh group (p < 0.05), whereas tissue OHP level was higher on day 90 than on day 5 in all three groups (p < 0.001). Also there was linear correlation between adhesion degree and tissue OHP levels (r= 0.86, p < 0.001). The study demonstrates that ABS PGA mesh has higher potential for adhesion formation than the NA PP mesh, probably related to the increased foreign body and inflammatory reactions during the absorption process of the mesh.

The preventive effect of heparin on stricture formation after caustic esophageal burns

BACKGROUND/PURPOSE Preventing thrombus formation after caustic esophageal ingestion has been proposed to have beneficial effects. Therefore, an experimental study was carried out to investigate the effects of heparin on the esophagus after caustic burns. METHODS Caustic esophageal burns were produced in rats by irrigation with 50% NaOH as described by Liu. Rats were divided into four groups as follows: group A, animals with esophageal burns, received placebo and underwent autopsy 48 hours after caustic injury; group B, animals with esophageal burns, received subcutaneous heparin treatment and underwent autopsy 48 hours after caustic injury; group C, animals with esophageal burns, received placebo and underwent autopsy 28 days after caustic injury; group D, animals with esophageal burns, received subcutaneous heparin treatment for 7 days and underwent autopsy 28 days after caustic injury. Histopathologic evaluation was performed in all groups, and collagen content of esophageal sections was analyzed by determination of hydroxyproline levels. RESULTS Submucosal vascular thrombosis was encountered in all group A animals but the submucosal venules and arterioles were patent in most of group B animals. Esophageal strictures did not develop in any of group D animals, although varying degree of esophageal stenoses were encountered in all animals of group C. The circumferences of the burned segment have been narrowed to 3+/-1 mm in group C rats. There was obvious collagen deposition in submucosa, and epithelial regeneration was not complete in group C rats. Submucosa and epithelial integrity seemed normal in group D animals. Hydroxyproline contents in group D were significantly lower compared with group C (P < .05). CONCLUSIONS Heparin has ameliorating effects on stricture formation after caustic esophageal burn. Those effects may occur through possible anticoagulant, antithrombotic, and endothelial protective effects, and modifying effects of heparin on wound healing.

An experimental study of the effect of aprotinin on intestinal adhesion formation.

BACKGROUND Depression of fibrinolysis is known to be a major mechanism for postoperative adhesion formation. Because aprotinin inhibits fibrinolysis it may lead to an increase in adhesion formation whereas its anti-inflammatory effects may lead to a decrease in adhesion formation. Our aim is to clarify conflicting results in previous literature. METHODS Basal levels of intestinal hydroxyproline (OHP) content and local fibrinolytic activity (LFA) were determined using naive groups. In the experiment groups, adhesions were created by scraping and creating a transient ischemia of a segment of terminal ileum. Group I and II rats were injected subcutaneous (s.c.) normal saline (NS) for 3 days and single dose intraperitoneal (i.p.) NS, respectively. Group III and IV rats were injected s.c. aprotinin for 3 days and single dose i.p. aprotinin, respectively. Group V rats were injected intramuscular methylprednisolone (MP) for 3 days. LFA and OHP levels were determined on the second and fifth postoperative days. The severity of adhesion formation was graded on the fifth day. RESULTS Aprotinin decreased both the severity of adhesions and OHP levels whereas MP decreased only the severity of adhesions. There was an early depression of LFA at the second day in both NS and MP groups increasing to basal levels at the fifth day. OHP levels showed significant correlation with adhesion severity. CONCLUSION Results showed that aprotinin decreased intra-abdominal adhesion formation probably by preventing early depression of LFA.

Epidermal growth factor-containing wound closure enhances wound healing in non-diabetic and diabetic rats

Background: This study was designed to elucidate the in vivo efficacy of epidermal growth factor (EGF) on wound healing in non diabetic and diabetic rats.

The effects of corticosteroids and vitamin A on the healing of tracheal anastomoses

OBJECTIVE This study investigates the deleterious effects of corticosteroids on tracheal anastomotic healing and the ability of vitamin A to reverse these effects in a rat model. METHODS Forty-two adult Wistar rats were randomly divided into five groups. The animals underwent tracheal transection and primary anastomoses. The groups were assigned as follows: Group I, sham (N=6); Group II, control (N=6); Group III, dexamethasone, 0.1 mg/kg/day intramuscularly (N=10); Group IV, dexamethasone 0.1 mg/kg/day intramuscularly+vitamin A 10000 IU/kg/day by gavages (N=10); and Group V, vitamin A 10000 IU/kg/day by gavages for a week (N=10). After 7 days, anastomotic healing was assessed by measurement of bursting pressure, hydroxyproline content and subsequent histological grading using the modified Ehrlich/Hunt scale. RESULTS Bursting pressures and hydroxyproline contents were as follows: Group I: 977+/-8 mmHg and 11.80+/-0.3 microg/mg (mean+/-standard error of the mean); Group II: 890+/-55 mmHg and 9.93+/-0.6 microg/mg; Group III: 555+/-26 mmHg and 11.90+/-1.3 microg/mg; Group IV: 873+/-73 mmHg and 10.24+/-2.2 microg/mg; Group V: 905+/-45 mmHg and 7.51+/-0.8 microg/mg, respectively. Bursting pressure of Group III was found to be significantly lower when compared to other groups (P<0.0001). However, statistical significance was not found among the study groups for the hydroxyproline content. Except for inflammatory cell infiltration, histological parameters including epithelial regeneration, fibroblast proliferation, collagen content, and angiogenesis demonstrated significant differences among the groups. CONCLUSION The present study demonstrates that dexamethasone significantly impairs the healing of tracheal anastomoses in rats and postoperative administration of vitamin A appreciably reverses this inhibitory effect. Patients receiving corticosteroids may benefit from vitamin A when undergoing prolonged intubation and laryngotracheal reconstruction.

Cod liver oil supplementation improves cardiovascular and metabolic abnormalities in streptozotocin diabetic rats

Abnormalities in the metabolism of essential fatty acids and the results of increased oxidative stress have been implicated in cardiovascular disorders observed in diabetes mellitus. This study, therefore, aimed to investigate the effects of cod liver oil (CLO, Lysi Ltd, Iceland), which comprises mainly an antioxidant vitamin A, n:3 polyunsaturated fatty acids (n:3 PUFAs), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), on cardiovascular abnormalities in streptozotocin (STZ)‐diabetic rats. Two days after single STZ (55 mg kg−1, i.p.) or vehicle injection, diabetes was verified by increased blood glucose, and non‐diabetic and diabetic rats were left untreated or treated with CLO (0.5 mL kg−1 daily, by intragastric probing) for 12 weeks. Plasma glucose, triacylglycerol and cholesterol concentrations were significantly elevated in 12‐week untreated‐diabetic rats; CLO provided better weight gain, entirely prevented the plasma lipid abnormalities, but partially controlled the glycaemia in diabetic rats. In isolated aorta rings, diabetes resulted in increased phenylephrine‐induced vasoconstriction and isoprenaline‐induced vasorelaxation, impaired endothelium‐dependent vasodilatation and unchanged responsiveness to sodium nitroprusside. CLO treatment completely prevented endothelial deficiency, partly corrected the phenylephrine‐induced vasoconstriction and did not affect the responses to isoprenaline and sodium nitroprusside in diabetic aorta. Diabetes also produced a marked decrease in the rate of spontaneously beating right atria and a significant increase in basal contractile force of left ventricular papillary muscle. The responsiveness of right atria to the positive chronotropic effect of isoprenaline was significantly decreased in diabetic rats, and was increased in CLO‐treated diabetic rats. The positive chronotropic effect of noradrenaline was markedly increased in diabetic atria, but prevented by CLO treatment. Diabetes also resulted in an increased positive inotropic response of papillary muscle to both noradrenaline and isoprenaline, which were prevented by CLO treatment. CLO treatment also resulted in lower tissue sensitivity (pD2) to these agonists in diabetic papillary muscle. Ventricular hydroxy‐proline content was found to be unchanged among the experimental groups. The ultrastructure of diabetic myocardium displayed various degenerations (i.e. intracellular oedema, myofibrillar fragmentation, condensed pleomorphic mitochondria, thick capillary irregular basement membrane, swollen endothelial cells), which were partially prevented by CLO treatment. We conclude that the supplementation with CLO is effective in preventing cardiovascular disorders observed in experimental diabetes.

Locally applied granulocyte-macrophage colony-stimulating factor improves the impaired bowel anastomoses in rats with long-term corticosteroid treatment

Inflammation is an essential component of the first phase of anastomotic wound healing, and it is suppressed by corticosteroids. The anti-inflammatory effect of corticosteroids is largely responsible for the impairment of wound healing in bowel anastomosis. It has been reported that local application of granulocyte-macrophage colony-stimulating factor (GM-CSF) improves the healing process in dermal wounds. In the present study, we investigated the effects of locally injected GM-CSF on anastomotic wound healing in long-term corticosteroid treated rats. Eighty male Sprague-Dawley rats were randomized into four groups. 1: control, 2: steroid, 3: steroid + local GM-CSF, 4: steroid + systemic GM-CSF. In groups 2, 3, and 4, methylprednisolone (5 mg/kg) was injected IM daily for 14 days. After 14 days, following anesthesia and laparotomy, colonic anastomosis was performed 3 cm away from the peritoneal reflection. In group 3, 50 mg GM-CSF was injected into the perianastomotic area. In group 4, 50 mg GM-CSF was applied subcutaneously. On postoperative day 3, repeat laparotomies were performed and bursting pressures, hydroxyproline levels, and histopathology examinations were studied. The mean values of bursting pressures and hydroxyproline levels in group 3, treated with steroid + local GM-CSF, were significantly higher than that of the group 2 and group 4 values. In the histopathology examination, the mean score of group 3 was significantly higher than that of groups 2 and 4. Our study indicates that local application of GM-CSF significantly improves the impaired anastomotic wound healing in rats treated with long-term corticosteroid.

The effects of local and sustained release of fibroblast growth factor on wound healing in esophageal anastomoses.

BACKGROUND/PURPOSE Postsurgical complications, such as anastomotic leaks in patients with esophageal atresia, have remained unchanged during the last 3 decades. Growth factors enhance healing in several wound-healing models. Therefore, an experimental study was used to evaluate the effects of local and sustained release of basic fibroblast growth factor (FGF) on wound healing in esophageal anastomoses. MATERIALS AND METHODS Twenty-four male Wistar albino rats, which were subjected to a 1-cm segmental resection of the abdominal esophagus followed by end-to-end anastomosis, were allocated into 3 groups. Group I, the control group, had no gelatin film applied to the anastomosis. In group II (gelatin film without FGF) and group III (gelatin film with FGF), anastomoses were covered with unloaded and 2.55 mug FGF-loaded gelatin films, respectively. On postoperative day 7, bursting pressures, histopathologic collagen deposition, and tissue hydroxyproline concentrations of the anastomoses were then analyzed and compared. RESULTS Mean bursting pressures, mean submucosal and muscular collagen deposition scores, and mean tissue hydroxyproline concentrations differed significantly between groups. Mean bursting pressures were 22.5 +/- 3.1 mm Hg in group I, 29 +/- 1.6 mm Hg in group II, and 63.2 +/- 6.8 mm Hg in group III (P < .001). Mean submucosal collagen deposition scores (group I: 0.7 +/- 0.2, group II: 0.7 +/- 0.1, group III: 1.5 +/- 0.2; P = .02) and mean muscular collagen deposition scores (group I: 0.8 +/- 0.2, group II: 0.8 +/- 0.1, group III: 1.8 +/- 0.1; P = .01) were significantly higher in FGF animals than the other in the other 2 groups. Mean tissue hydroxyproline concentrations were 2.4 +/- 0.5 microg/mg in group I, 3.9 +/- 0.4 microg/mg in group II, and 6.0 +/- 1.0 microg/mg in group III (P = .007). CONCLUSION Local and sustained release of FGF enhanced wound healing in esophageal anastomoses in this animal model.

An Experimental Study of the Adhesive Potential of Different Meshes

OBJECTIVE To assess the adhesive potential and incidence of incisional hernia with three meshes. DESIGN Open experimental study. SETTING Surgical Research Laboratory, Turkey. ANIMALS 75 Wistar albino rats INTERVENTIONS Abdominal walls were excised, and defects closed primarily or with polyglactin 910, polypropylene, or dura mater. Adhesions were graded and hydroxyproline concentrations measured on days 14 and 180. On day 180, the incidence of incisional hernia, and the grades of inflammation and fibrosis were also recorded. RESULTS The polyglactin 910 group had a higher adhesion grading than the control and dura mater groups on day 14, whereas the polypropylene group had higher adhesion grading than controls. Both polypropylene and polyglactin 910 groups had significantly higher concentration of hydroxyproline than the control and dura mater groups. On day 180, the polypropylene group had a higher adhesion grading than the controls. There were no differences in hydroxyproline concentrations, incidence of hernias, or grading of fibrosis levels among the groups. CONCLUSION Polyglactin 910 induced more fibrotic adhesions in the early postoperative period whereas polypropylene did in both the early and late postoperative periods.

The effect of erythropoietin on healing of obstructive vs nonobstructive left colonic anastomosis: an experimental study.

BackgroundAnastomotic leakage is an important problem following primary resection in the left colon and is even more prominent when obstruction is present. We aimed to evaluate the possible effects of erythropoietin on the healing of anastomosis under both obstructive and non-obstructive states.MethodsForty male Wistar albino rats were divided into four groups. In group I, two cm left colonic resection and primary anastomosis were done. In group II, left colon were completely ligated and 24 hours later animals were re-operated for segmental resection. The same procedures were performed for rats in group III and IV in respect to group I and II and, 500 IU/kg a day erythropoietin were given in the latter two groups for seven days. For the quantative description of anastomotic healing mechanical, biochemical and histopathological parameters were employed on the seventh day and the animals were sacrificied.ResultsAlthough erythropoietin had positive effects on bursting pressure in group IV when compared to group II, it has no effect in group III. Despite the increased tissue hydroxyproline levels in group IV, erythropoietin failed to show any effects in group III.Erythropoietin had positive effects on neovascularization, fibroblast proliferiation and storage of collagen in group IV.ConclusionWe failed to find any direct and evident effects of erythropoietin on healing of left colonic anastomosis. On the other hand, erythropoietin might prevent negative effects of obstruction on healing.