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Purpose: The aim of the study was to investigate the effect of angiogenesis inhibition by bevacizumab, a monoclonal anti-vascular endothelial growth factor (VEGF) antibody, on the healing process of colonic anastomoses in rats, assessing some specific involved factors. This new agent is used mainly in metastatic colorectal cancer. The angiogenesis plays an important role in both wound healing and metastatic invasion and spread of malignant cells. There has not been any evidence assessing the optimal time for its safe use in operated patients., Materials and Methods: Forty Wistar rats were randomly allocated into four equal groups. A colonic anastomosis was performed in all rats. Half of them received intraoperatively a single dose of bevacizumab 5 mg/body weight and the rest received placebo. The animals were sacrificed on the 7th (Avastin 7th, placebo 7th) and 14th (Avastin 14th, placebo 14th) postoperative day. The anastomosis was resected and sent for histological study and for tissue biochemical assays (VEGF, endothelin-1 (ET-1), C-reactive protein (CRP), pro-oxidant-antioxidant balance (PAB), carbonylated proteins, hydroxyproline) using specific enzyme-linked immunosorbent assay kits. For statistical analysis, the Mann-Whitney U test was used (of statistical significance when P < 0.05)., Results: No complication or anastomotic dehiscence was observed. Histology did not reveal statistically significant differences between groups concerning degree of inflammation, fibroblasts, collagen, and fibrosis. Likewise, hydroxyproline levels did not differ. However, some statistically significant differences were found in VEGF, CRP and carbonyl proteins (Avastin 7th vs placebo 7th, placebo 14th vs placebo 7th), ET-1, and PAB (Avastin 14th vs Avastin 7th), which did not finally affect the collagen synthesis marker hydroxyproline, nor did the anastomotic strength., Conclusions: Bevacizumab, when administered intraoperatively, has no significant effect on colon anastomotic healing in rats despite a transient mild ischemia.

Introduction: The purpose of this experimental study was to determine the effect of oxaliplatin on the integrity of colonic anastomoses which were under oxaliplatin administration., Materials and Methods: Thirty rats were randomized to two groups. After resection of a 1-cm segment of the transverse colon, an end-to-end sutured anastomosis was performed. Rats of the control group were injected with 3 ml of 0.9% sodium chloride solution and in the oxaliplatin group with 2.4 mg/kg of oxaliplatin intraperitoneally immediately after surgery and for seven postoperative days. All rats were sacrificed on the tenth postoperative day, and the anastomoses were examined macroscopically and graded histologically. Rats were measured for anastomotic bursting pressures and tissue hydroxyproline levels., Results: The body weight changes were significantly greater in the oxaliplatin group (p = 0.005). Anastomotic dehiscence occurred only in the oxaliplatin group. The adhesion formation was significantly increased in the group of oxaliplatin compared to the control group (p = 0.001). The colonic bursting pressure was significantly lower in the oxaliplatin group compared to the control group (p < 0.001). The mean inflammatory cell infiltration was significantly lower in the oxaliplatin group (1.00 vs. 2.33, p < 0.001). The mean neoagiogenesis was significantly lower in the oxaliplatin group (0.80 vs. 2.20, p < 0.001). The mean collagen deposition was significantly lower in the oxaliplatin group and the mean fibroblast activity was significantly lower in the oxaliplatin group (1.27 vs. 2.53, p < 0.001). Hydroxyproline concentration was significantly lower in the oxaliplatin group (p < 0.001)., Conclusion: Intra- and postoperative intraperitoneal administration of oxaliplatin definitely impairs healing of colonic anastomoses in rats.

Aim: The aim of this experimental study was to investigate the effect of intraperitoneal administration of oxaliplatin on the healing of colonic anastomoses when injected immediately after colon resection., Materials and Methods: Thirty male Wistar rats were used. During the operation, the rats were randomized to two groups of 15 rats each. Immediately after colonic anastomoses were performed, the rats were injected intraperitoneally with either 3 ml of 0.9% NaCl solution or oxaliplatin (2.4 mg/kg body weight) depending on their group. All rats were killed on the eighth postoperative day. The anastomoses were examined macroscopically. The anastomotic bursting pressures were recorded, the anastomoses graded histologically, and the hydroxyproline tissue contents determined., Results: Anastomotic leakage was noted in four rats (26.7%) of the oxaliplatin group, whereas no anastomotic dehiscence was detected among rats of the control group (p = 0.016). The adhesion formation at the anastomotic sites and the inflammatory cell infiltration were significantly higher in the oxaliplatin group than in the control group (p = 0.001). The bursting pressures (p = 0.001), the hydroxyproline tissue content (p = 0.001), the neoangiogenesis (p = 0.033), the fibroblast activity (p = 0.001), and the collagen deposition (p = 0.001) were significantly lower in the oxaliplatin group in comparison to the control group., Conclusion: The immediate postoperative intraperitoneal administration of oxaliplatin seems to impair healing of colonic anastomoses in rats.