Responses of enterocyte microvilli in experimental diabetes to insulin and an aldose reductase inhibitor (ponalrestat).
The small intestine of 12-week-old streptozotocin-diabetic rats was examined by light and transmission electron microscopy in order to study the effects of alternative treatments on microvillous morphology. Four groups were examined: untreated diabetic rats, insulin-treated diabetics and rats treated with an aldose reductase inhibitor (ponalrestat) given with and without insulin. Numbers and dimensions of microvilli at the apex of columnar absorptive epithelial cells (enterocytes) were estimated using stereological principles. Values were obtained for the organ as a whole as well as for different sites along its length. In the untreated diabetic intestine, the mean (standard error of mean) number of microvilli was 4.5 (0.8) x 10(12) with a total surface area of 1.9 (0.50) m2. On average, the microvilli were 1.1 (0.08) microns long, 104 (3.8) nm in diameter and packed on the villous surface at a density of 3400 (50) per 100 microns 2. Their length at least varied with intestinal location. Significant effects of insulin therapy were detected. In contrast, the study failed to find any significant effect of aldose reductase inhibition on any variable except microvillous packing density.
Department of Human Morphology, Queen's Medical Centre, University of Nottingham, U.K.
M
M
Williams
T M
TM
Mayhew
D000449:Aldehyde Reductase / Q000037:antagonists & inhibitors*; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy* / Q000473:pathology; D004848:Epithelium / Q000187:drug effects / Q000648:ultrastructure; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology*; D007421:Intestine, Small / Q000187:drug effects* / Q000648:ultrastructure; D008871:Microvilli / Q000187:drug effects / Q000648:ultrastructure; D010793:Phthalazines / Q000494:pharmacology*; D051381:Rats
D007004:Hypoglycemic Agents; D007328:Insulin; D010793:Phthalazines; C042829:ponalrestat; D000449:Aldehyde Reductase