Laxatives and intestinal epithelial cells: a morphological study of epithelial cell damage and proliferation.

Experimental studies indicate that anthranoid laxatives may induce epithelial damage. In addition they induce the release of prostaglandins. Epithelial cell damage and release of prostaglandins are two pathways by which epithelial cell proliferation could be influenced. Other laxatives including fermentable laxatives like lactulose may also influence large intestine cell proliferation by the trophic effect of the fermentation products such as short chain fatty acids. For these reasons an in vitro study was performed on human intestinal epithelial cells in culture to investigate the direct damaging effect of rhein anthrone. Ultrastructural examination showed a dose dependent direct damage. In addition an in vivo study in rats was performed to compare the short and long term effect of sennosides, bisacodyl, sodium picosulphate and lactulose on epithelial cell proliferation in the ileum and large intestine. Cell proliferation was examined by the BrdUrd labeling technique after 2, 6 and 12 weeks of continuous treatment. Studies in control animals show that the Labeling Index (LI) is higher in the caecum compared with other segments of the colon, and higher in the ileum than in the colon. Treatment with sennosides, bisacodyl and sodium picosulphate 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 at the end of the study. The proliferative pattern along the crypts remains unchanged with all the laxatives throughout the study. It appears therefore that 'contact' laxatives have no major influence on ileal and colonic epithelial cell proliferation.