Prevention of postoperative peritoneal adhesions by O-carboxymethyl chitosan in a rat cecal abrasion model.

PURPOSE Post-surgical adhesion formation can result in significant morbidity and mortality. N,O-carboxymethyl chitosan (N,O-CMC) has been previously shown to be effective in the prevention of postsurgical adhesion formation. In this study, we evaluated the ability of O-carboxymethyl chitosan (O-CMC), another chitosan derivative generated by carboxymethylation of chitosan's oxygen centers, to reduce postsurgical adhesion development. METHODS Twenty male Sprague-Dawley rats (250 +/- 20 g) were divided into two equal groups: O-CMC group and saline (control) group. All rats underwent a midline laparotomy and the cecum was abraded to cause petechial hemorrhages. Following peritoneal injections of either saline or O-CMC, the incisions were closed. Seven days after surgery, the animals were killed and adhesion formation was scored. Tissue samples from the adhesions were examined histochemically. RESULTS Adhesion formation was significantly decreased in the O-CMC group (P < .001) in comparison with the control group. Furthermore, significantly less collagen (P < .001) and fewer inflammatory cells and fibroblasts were detected in the O-CMC-treated animals. Additionally, a significantly (P < .05) lower level of TGF-beta1 expression was found in the O-CMC group. CONCLUSION O-CMC appears to be effective in the prevention of postoperative peritoneal adhesion formation, which may be attributed to decreased accumulation of inflammatory cells and fibroblasts and reduced collagen synthesis.