DIRECT EVIDENCE OF OXIDATIVE DAMAGE IN ACUTE AND CHRONIC PHASES OF EXPERIMENTAL COLITIS IN RATS

During inflammatory colitis in man and experimental animals, the produ ction of free radicals increases. This study evaluated the histologica l pattern and biochemical parameters of oxidative damage during acute and chronic colitis induced by 2,4,-trinitrobenzenesulfonic acid + eth anol in rats. On the samples of scraped mucosa of six groups of rats, one not treated, one killed after 1 hr, and those killed one, two, fou r, and eight weeks after the induced-damage, we determined the histolo gical and superoxide dismutase activity and the concentration of lipop eroxides, malonyldialdheyde, and reduced glutathione. After 1 hr, the mucosal damage and superoxide dismutase activity were slight; glutathi one, lipoperoxides, and malonyldialdheyde were significantly increased . At one week, the histological damage was severe, decreasing progress ively, and significantly correlated to superoxide dismutase activity. Lipoperoxides and malonyldialdheyde were high throughout the study. Gl utathione was significantly increased at one and two weeks and dramati cally decreased thereafter. Therefore, in experimental colitis the cas cade of free-radical production induces a constant self-maintaining li poperoxidation and consumes the cellular antioxidant capability.