Participation of mast cells in colitis inflammation induced by dextran sulfate sodium

We investigated the participation of mast cells in colitis inflammation induced by dextran sulfate sodium (DSS). The damage score and myeloperoxidase (MPO) activity were measured to confirm the occurrence of colitis. Rat mast cell protease (RMPCP) II levels in the serum were estimated as an index of mast cell degranulation. Tissue RMCP I and RMCP II levels in the rectum were also measured as markers of the numbers of connective tissue mast cells (CTMCs) and mucosal mast cells (MMCs), respectively. Administration of 4% DSS resulted in time-related increases in damage score, MPO activity and serum RMCP II levels, which were statistically significant at 7 and 11 days after treatment. Tissue RMCP I and RMCP II levels in the rectum were also increased significantly at 7 and 11 days, and 11 days, respectively after free drinking of 4% DSS. These results suggested that mast cells proliferated or the amount of protease per mast cell increased in the sites of inflammation induced by DSS, and that these mast cells may modulate the disorders observed in DSS-induced colitis.