title: Enzyme changes in remodelling epithelial cells: a histochemical study of the rat jejunum in vivo during and following exposure to deoxycholic acid.
abstract: Loops of rat jejunum were exposed in vivo to different concentrations of deoxycholic acid (DOC; 0, 2.5, 5, 10 and 20 mM). Following a 30 min exposure period, DOC was washed out of the loops and the intestines were allowed to recover for 15 or 150 min. Frozen tissue for enzyme histochemistry was collected during exposure and following the recovery periods. As shown previously, exposure to DOC caused a dose-dependent loss of epithelial cells at the villous tips and denudation of the lamina propria. Flattened epithelial cells bordering the denuded areas were, however, responsible for a rapid restoration of epithelial continuity, which was completed within 15 min. In the present study, these flattened cells showed normal reactivity for non-specific esterase and succinate dehydrogenase. In contrast, following a prolonged recovery period (150 min), a subpopulation of enterocytes at the villous tips that otherwise appeared normal showed decreased reactivity for brush border enzymes and non-specific esterase, and a positive reaction for mucin. A shutdown in the synthesis of cytoplasmic enzymes and redistribution of cell surface enzymes could be responsible for these late occurring enzyme changes, that were consistently observed after 150 min of recovery from DOC at 20 mM. Alternatively, retention of goblet cells and/or a modification in enzyme synthesis may explain the presence of mucin that was demonstrated in the epithelial cells which had low enzyme reactivity.
authors.affiliation: Department of Morphology, Genetics and Aquatic Biology, Norwegian College of Veterinary Medicine, Oslo.
authors.forename: J A
authors.initials: JA
authors.lastname: Matovelo
authors.forename: T
authors.initials: T
authors.lastname: Landsverk
authors.forename: R B
authors.initials: RB
authors.lastname: Sund
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D003840:Deoxycholic Acid / Q000494:pharmacology*; D004798:Enzymes / Q000378:metabolism*; D004950:Esterases / Q000378:metabolism; D006651:Histocytochemistry; D007413:Intestinal Mucosa / Q000187:drug effects / Q000201:enzymology*; D007583:Jejunum / Q000187:drug effects / Q000201:enzymology*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013385:Succinate Dehydrogenase / Q000378:metabolism
chemical_list: D004798:Enzymes; D003840:Deoxycholic Acid; D013385:Succinate Dehydrogenase; D004950:Esterases; D000469:Alkaline Phosphatase; D000252:Calcium-Transporting ATPases