Influence of omentectomy on peritoneal defense mechanisms in an experimental model of intra-abdominal infection.

BACKGROUND/AIM: The omentum has an important role as part of peritoneal defense mechanisms. The aim of this study is to show the bactericidal activity of peritoneal fluid and the role of the omentum as a peritoneal defense mechanism in experimental animals with intra-abdominal infections. METHODS: 40 male Spraque-Dawley rats weighing between 250 and 300 g were used in this study. The rats were randomly divided into four groups consisting of 10 animals. The operative procedures were done under sterile conditions. In group I sham laparotomy was done. In group II, the distal part of the cecum was ligated, and cecum perforation was performed. In group III, total omentectomy was performed after cecal ligation and perforation. In group IV only omentectomy was performed. Baseline and 2- and 4-hour peritoneal fluid samples were taken using a Pasteur pipette during laparotomy under anesthesia. Total peritoneal cells counts, bactericidal activity of peritoneal fluid, and types of phagocytic cells in the peritoneal fluid were assessed. RESULTS: As compared with baseline values, the total peritoneal cell counts were increased at the 2nd and 4th h in all groups (p < 0.05). A significant increase was observed after 4 h as compared with 2 h in sham laparotomy, cecal ligation+perforation+omentectomy, and omentectomy groups (p < 0.05). A significant increase in the cell counts after 2 h was found in the other groups when compared to the sham laparotomy group (p = 0.0001). After 4 h, there was a significant difference between the groups, but especially prominent in the cecum ligation+perforation+omentectomy group (p = 0.0001). Proliferating colony counts of Escherichia coli and Pseudomonas Aeruginosa decreased after 2 h, and there was no proliferation in the subsequent cultures. It was observed that the macrophage counts significantly increased after 2 and 4 h as compared with baseline in intragroup assessments (p = 0.0001). In the intergroup assessment, an increase was observed in the macrophage counts at baseline and after 2 and 4 h, and this was significant in the cecal ligation+perforation+omentectomy group (p = 0.0001). In the omentectomy group, a significant decrease was observed in the macrophage counts between the 2nd and 4th h (p = 0.0001). CONCLUSION: Removal of the omentum in the presence of intra-abdominal infections causes the peripherally derived macrophages to take over the defensive role of macrophages of peritoneal origin as a compensatory mechanism, thus the peritoneal bactericidal activity against E. COLI, the major pathogen in intra-abdominal infections, does not change after omentectomy.

The influence of omentectomy on the inflammatory phase of anastomotic healing.

BACKGROUND/AIMS: Proper wound healing of the alimentary tract is essential for the prevention of the significant mortality and morbidity associated with complications. The effects of omentectomy on the inflammatory phase of anastomotic healing in rats were examined. METHODOLOGY: Sixty male Wistar-Albino rats that weighed about 200-220 g were used in this study. Animals were divided into three groups as colon anastomosis, colon anastomosis + partial omentectomy and colon anastomosis + total omentectomy. On the third postoperative day, all animals were sacrificed under anesthesia. Bursting pressure of anastomosis amounts and types of cells in the anastomosis, and nitric oxide, malondialdehyde, superoxide dismutase levels in the anastomosis and serum was examined. RESULTS: Bursting pressure values were 102.60 +/- 13.41 mm Hg, 105 +/- 10.80 mm Hg and 102.50 +/- 11.12 mm Hg in the colon anastomosis, colon anastomosis + partial omentectomy and colon anastomosis + total omentectomy groups, respectively (P > 0.05). A significant increase in macrophage count was found in the colon anastomosis + total omentectomy group when compared with the colon anastomosis group (P = 0.02). According to the comparisons with percentages, there was a significant difference in lymphocyte counts between colon anastomosis and colon anastomosis + total omentectomy groups (P = 0.04). The blood level of superoxide dismutase was higher in the colon anastomosis + total omentectomy group than the other two groups, and in the colon anastomosis + partial omentectomy group than the colon anastomoses group (P = 0.0001). There was a significant increase in the blood level of nitric oxide when comparing the colon anastomosis + total omentectomy group with colon anastomosis group (P = 0.02). The tissue level of malondialdehyde was higher in the colon anastomosis + total omentectomy group than the other two groups (P < 0.0001). CONCLUSIONS: Omentectomy may influence the outcome of the inflammatory phase of wound healing in rats. But systemic compensatory regulation of body can tolerate these detrimental effects and wound healing continues in its regular manner.