Comparison of a chymase inhibitor and hyaluronic acid/carboxymethylcellulose (Seprafilm) in a novel peritoneal adhesion model in rats

Adhesion formation that occurred after alkali-induced injury of the cecum was used as a novel adhesion model in rats, and it was compared with that of a common adhesion model after abrading the cecum. Using the novel adhesion model, inhibition of adhesion formation by a chymase inhibitor, Suc-Val-Pro-Phe(P)(OPh)(2), and by sodium hyaluronate/carboxymethylcellulose (Seprafilm) was evaluated, and their mechanisms were assessed. The degree of adhesion formation was more severe and more stable in the alkali-induced injury model than in the abrasion-induced injury model. Both the chymase inhibitor and Seprafilm showed significant attenuation of the degree of adhesion 14 days after alkali-induced injury. Chymase activity in the cecum was significantly increased after alkali-induced injury, but it was significantly attenuated by the chymase inhibitor and Seprafilm. Myeloperoxidase and transforming-growth factor (TGF)-β levels were significantly increased after alkali-induced injury, but they were attenuated by both the chymase inhibitor and Seprafilm. At the level of the adhesions, the numbers of both chymase-positive cells and TGF-β-positive cells were significantly increased, but their numbers were reduced by the chymase inhibitor and Seprafilm. In conclusion, a chymase inhibitor attenuated the degree of adhesions to the same degree as Seprafilm in a novel peritoneal adhesion model that was more severe and more stable than the common adhesion model, and not only the chymase inhibitor, but also Seprafilm reduced the chymase increase at the adhesions.