Effect of bile salt-binding resins on the morphology of rat jejunum and colon. A scanning electron microscopy study.

One mechanism suggested to account for the hypocholesteremic effect of dietary fibers is their ability to sequester bile salts. Since bile salts have been found to alter intestinal structure, the morphological effects of several commonly used, xenobiotic, bile salt-binding agents was investigated. Wistar rats were fed a purified stock diet, ad libitum, for 6 weeks containing either 2% cholestyramine, 2% colestipol, or 2% DEAE-Sephadex. The bile salt-binding capacity of these substances was tested in vitro using taurocholate and glycocholate. The effect of in vivo feeding of the resins was to evoke ultrastructural topographical deviations from control appearance in both jejunal and colonic mucosae. Colonic cell injury was more severe than that observed in the jejunum of both colestipol- and DEAE-Sephadex-fed animals while the reverse was true for the rats fed cholestyramine. The degree of distortion in each condition was positively correlated with the extent of bile salt-binding capability in vitro. The rank order of both effects in terms of increasing severity was DEAE-Sephadex less than colestipol less than cholestyramine.