Sulphasalazine, olsalazine and sulphapyridine induce mitogenic actions in the rat intestinal epithelium

Our aim was to study the influence of sulphasalazine (SASP), olsalazine (ADS) and sulphapyridine (SP) on the cell kinetics of the intestinal epithelium in conventional rats. Groups of rats were treated with SASP, ADS or SP for 9 days. After an intraperitoneal injection of a metaphase blocker, the rats were killed and the jejunum, ileum and colon were examined in histological sections by means of the cumulative mitotic index (MI), growth fraction and number of cells in crypts and villi. SP increased both the MI in the jejunum, ileum and colon and the number of crypt cells (p<0.05 vs controls). In contrast, SASP and ADS increased the MI only in the colonic epithelium (p<0.05 vs controls). The growth fraction was essentially unaffected. Our results suggest that SASP. SP and ADS have a selective compartment-dependent proliferative action on the epithelium of the intestinal tract.