MORPHOLOGIC CHANGES IN INTESTINAL-MUCOSA WITH URINARY CONTACT - EFFECTS OF URINE OR DISUSE

Purpose: To evaluate the morphological changes induced in bypassed ile al and colonic segments and the influence of the urine an the mucosal histology. Materials and Methods: In a rat model, an isolated ileocolo nic segment was used for construction of an ileocolocystoplasty or an exteriorized blind loop. Sham-operated animals were used for control. Results: In ileal mucosa, villi and microvilli were better preserved w hen exposed to urine than when deprived of contact with luminal conten t, Numerical reduction of microvilli was found in colonic mucosa depri ved of luminal content, In colonic mucosa exposed to urine some areas were denuded of microvilli and-showed blebs. Findings of intact tight junctions in all specimens implied that an important morphological req uirement of maintained epithelial barrier function is present in mucos a deprived of normal luminal stimulation and also after contact with u rine, The intracellular ultrastructural changes in both colon and ileu m were similar in the 2 groups. How ever, there were more solitary rib osomes lying free in the mucosa exposed to urine, indicating depressed or arrested protein synthesis. Conclusions: Mucosa in contact with ur ine seems to maintain surface characteristics better than mucosa depri ved of luminal stimulation, indicating that factors present in the uri ne may be important for the epithelial cell physiology. Certain intrac ellular changes were found more often in mucosa exposed to urine, but there were no major differences. The changes noticed may indicate ente rocyte adaptation to a new physiologic environment.