EVALUATION OF A CARBOXYMETHYLCELLULOSE SPONGE FOR PREVENTION OF POSTOPERATIVE ADHESIONS

BACKGROUND: A novel lyophilized carboxymethylcellulose (CMC) sponge ha s been developed for prevention of surgical wound adhesions. One poten tial mechanism for preventing abdominal adhesion is suppression of the cytokine transforming growth factor beta (TGF-beta) and other macroph age derived fibroblast stimulating factors that partially mediate adhe sion formation. METHODS: To study tile efficacy and mechanisms of acti on of the CMC sponge, we performed standard cecal denudation and abdom inal wall apposition on rats, A CMC sponge or a commercially available adhesion preventive barrier (Interceed) was placed on the denuded sur face, After 14 days, adhesion severity was graded blindly on a scale r anging from 0 (no adhesion) to 5 (severe adhesion). TGF-beta expressio n was determined by immunocytochemical staining, To assess the secreti on of macrophage derived fibrogenic factors in control and CMC rats, l abeled thymidine and proline uptake and hydroxyproline production were measured in NRK rat fibroblasts cultured with conditioned medium of p eritoneal macrophages. RESULTS: The severity of adhesions in the CMC s ponge group (0.7 +/- 0.3) was significantly lower than in the Intercee d or control groups (2.2 +/- 0.3; 4.6 +/- 0.1), In control animals TGF -beta expression in endothelium and fibroblasts was maximal on day 3. Neither CMC nor Interceed reduced this expression, Conditioned media d erived from sponge-exposed postsurgical peritoneal macrophages did not inhibit fibroblast growth or collagen formation. CONCLUSIONS: In this model the CMC sponge was more effective than Interceed in preventing postoperative adhesions. Its action was not due to inhibition of TGF-b eta expression or macrophage derived fibrogenic factors. These data hi ghlight the primary importance of local barrier effect in adhesion pre vention.