PREVENTIVE EFFECT OF IMMUNOSUPPRESSIVE AGENTS AGAINST INDOMETHACIN-INDUCED SMALL-INTESTINAL ULCERS IN RATS

The mechanism of nonsteroidal antiinflammatory drug-induced intestinal ulcers is not clearly understood. To evaluate whether immunosuppressants have a preventive effect against indomethacin-induced gastrointestinal damage, we investigated the effects of prednisolone, cyclosporin, and the newly developed immunosuppressant FK-506 in intracolonically indomethacin-treated rats: 24 mg/kg of indomethacin, administered intracolonically for two days, caused gastric ulcers and two types of small intestinal ulcers (longitudinal ulcers and scattered small ulcers). Pretreatment with intraperitoneal immunosuppressants reduced the size of gastric ulcers. Both cyclosporin (10 mg/kg) and FK-506 (I mg/kg, 2 mg/kg) treatments significantly reduced the incidence and the length of the longitudinal ulcers of the small intestine when compared to the vehicle-treated controls, whereas prednisolone (20 mg/kg) did not show any preventive effect. Furthermore, the number of small scattered ulcers of the small intestine was significantly reduced by the high dose of FK-506 (2 mg/kg), but not by cyclosporin or prednisolone. These findings indicate that immunosuppressants have protective and antiinflammatory effects in indomethacin-induced gastroenteropathy, suggesting that cytokines may be important mediators in the pathogenesis of enteropathy induced by nonsteroidal antiinflammatory drugs.