EFFECTS OF CONTACT LAXATIVES ON INTESTINAL AND COLONIC EPITHELIAL-CELL PROLIFERATION

Experimental studies indicate that laxatives may induce epithelial dam age. In addition, some laxatives induce the release of prostaglandins. Epithelial cell damage and release of prostaglandins are two pathways by which epithelial cell proliferation could be influenced. Furthermo re, fermentable laxatives like lactulose may influence large intestine cell proliferation by the trophic effect of the fermentation products such as short-chain fatty acids. For these reasons an in vivo study i n rats was performed to compare the short- and long-term effect of sen nosides, bisacodyl, sodium picosulfate and lactulose on epithelial cel l proliferation in the ileum and large intestine. Cell proliferation w as examined by the BrdUrd labelling technique after 2, 6 and 12 weeks of continuous treatment. Studies in control animals show that the Labe ling Index (LI) is higher in the cecum compared with other segments of the colon, and higher in the ileum than in the colon. Treatment with sennosides, bisacodyl and sodium picosulfate does not influence the LI in the ileum and induces no statistically significant increase of the LI when the treated groups are compared with the control group. The p roliferative pattern along the crypts remains unchanged with all the l axatives throughout the study. It appears therefore that 'contact' lax atives have no major influence on ileal and colonic epithelial cell pr oliferation and should not be regarded as tumor-promoting substances.