The Influence Of Losartan On Histopathological Changes Of The Middle Cerebral Arteries In Diabetic Rats

Objective The aim of this study was to demonstrate histopa-thological alternation of the middle cerebral arteries in streptozotocin-induc -ed diabeticrats and assess the possible effect of losartan on the alternation.MethodsMale wistar rats were randomly divided into normal control group (NC,n=8),diabetic control group(DM1,n=7) and diabetic group treated with losartan(DM2,n=8)[10mg/(kg.d)].Diabetic rats were streptozotocin-induced.Sham injection,control rats were studied in parallel.Three groups were administered for 14 weeks after injection. At14th week, plasma levels of edothelin(ET), angiotensinII (AngII) were determined by radioimmunoass-ay respectively.The arteries were examined under light and electron microscope.ResultsIn DM1 group,plasma levels of ET and AngII were increased significantly compared with NC group(p<0.05).In DM2 group, plasma level of AngII were elevated more significantly while plasma ET level declined (p<0.05) compared with DM1 group. Therewere mitochon- dria edema vacuolization and some endothelial cells necrosisand exfoliation. The multiplication of smooth muscular cells in the artery wall was promi-nent.The artery wall, in DM1 group ,became more thicker than that in NC group,but a little pathological changes in DM2 group.Conculsions Plasma levels of ET and AngII of diabetic rats are pathologically increased.The structure and function of the MCAs undergo significantly alternation in DM1 group.Losartan can effectively prevent the alternation.