Down-regulation by bucillamine of lamina propria leucocytes in the rat colitis model

1. The efficacy of bucillamine has been reported in various inflammatory mo dels. 2. In the present study, the effects of 2 weeks administration of bucillami ne on hapten-induced experimental rat colitis were analysed, The gross morp hological damage score was evaluated and the expression of CD4, CDS, CD11a, CD11b, CD25, CD54 and class 11 major histocompatibility complex (MHC) anti gen was investigated by immunohistochemical methods. 3. Mean bodyweight was significantly increased in colitic rats given 750 mu g bucillamine compared with colitic rats given vehicle (distilled water), Gross morphological damage was significantly less in colitic rats given 250 or 750 mu g bucillamine compared with rats given vehicle, 4. Immunohistological studies revealed that CD4 CDlla, CD11b, CD54 and clas s II MHC antigen expression of infiltrating leucocytes was significantly lo wer in rat colonic mucosa treated with bucillamine, 5. From these findings, it appears that bucillamine may act through the dow n-regulation of the activation of lamina propria leucocytes in hapten-induc ed rat colitis.