Effect of Z-103 on TNB-induced colitis in rats.

Z-103 is a chelate compound consisting of zinc ion and L-carnosine. In this study, we investigated the protective effect of Z-103 against colonic damage induced by 2,4,6-trinitrobenzene sulfonic acid (TNB) in rats. Colonic inflammation was induced by administering TNB dissolved in 50% ethanol (120 mg/ml) in male Wistar rats (total volume of 0.25 ml per rat) following a 48-hour fast. After the administration of TNB, Z-103 was given at a dose of 30 mg/kg per rat for 1 week. A second group of rats received sulfasalazine (SASP) at 300 mg/kg and a third group of rats received 30 mg/kg of ZnSO4 for 1 week. Colonic inflammation was assessed 1 week following TNB administration. Both macro- and microscopic evaluation showed that the inflammatory responses induced by TNB were reduced by treatment with Z-103, SASP and ZnSO4. The score (graded from 0 to 5 according to the macroscopic lesions) and colonic wet weight (distal 8 cm of the colon) were significantly decreased by treatment with Z-103, SASP and ZnSO4. The increase in thiobarbituric acid-reactive substances in the colonic mucosa following TNB administration were inhibited in the Z-103 and SASP groups. These results suggest that Z-103 is as effective against TNB-induced colitis as SASP.