The inhibitory effect of magnesium hydroxide on the bile acid-induced cell proliferation of colon epithelium in rats with comparison to the action of calcium lactate.

The modulating effects of magnesium hydroxide and calcium lactate on the cholic acid-induced hyperproliferation of cells in rat colon epithelium were investigated. Rats were divided into six groups (10 rats/group) and fed the following diets for 8 weeks: 0.25% cholic acid alone (group 1), cholic acid plus 0.2% magnesium hydroxide (group 2), cholic acid plus 1.18% calcium in the form of calcium lactate (group 3), calcium lactate alone (group 4), magnesium hydroxide alone (group 5) and the basal diet alone (group 6). At the end of the experiment, all rats were killed for the immunocytochemical examination of 5-bromo-2'-deoxyuridine (BrdU) incorporation in the cell nuclei of colonic epithelium. Magnesium hydroxide reduced the cholic acid-induced BrdU incorporation by 33% at the distal part and 40% at the proximal part. Calcium lactate also reduced the BrdU incorporation by 48% and 51% respectively. Exposure of magnesium hydroxide or calcium lactate alone had no influence on BrdU incorporation. The results suggest that magnesium hydroxide might exert anti-carcinogenic effects as does calcium by reducing increased cell proliferation of colonic epithelium induced by toxic effects of bile acids, which are regarded as colon tumor promoters or cocarcinogens.