title: Histochemical assessment of nitric oxide synthase activity in aortic endothelial cells of streptozotocin-induced diabetic rats.
abstract: Impaired endothelium-dependent relaxation of blood vessels is a common feature in diabetes, but the exact underlying mechanisms have not yet been clarified. In present study, endothelium-dependent vasorelaxation of aortic rings were evaluated in vitro in streptozotocin (STZ)-induced diabetic and age-matched control rats. Moreover, nitric oxide synthase (NOS) activity of aortic endothelial cells was assessed in both diabetic and healthy rats using histochemical staining for nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase activity. The results showed a significant decrease of endothelium-dependent relaxation in response to acetylcholine (ACh) in diabetic rings, compared with controls, that was accompanied by a remarkable attenuation of NOS activity in diabetic sections of rat aorta stained for NADPH-diaphorase. Furthermore, a membrane disruption of some endothelial cells was also observed in all diabetic sections. It can be concluded that a decrease in NOS activity together with a disruption of endothelial cell membrane play a major role in endothelial dysfunction observed in diabetes.
authors.affiliation: Razi Institute for Drug Research, Iran University of Medical Sciences, P.O. Box 14155-6183, Tehran, Iran
authors.forename: M
authors.initials: M
authors.lastname: Shafiei
authors.forename: M
authors.initials: M
authors.lastname: Nobakht
authors.forename: M
authors.initials: M
authors.lastname: Fattahi
authors.forename: L
authors.initials: L
authors.lastname: Kohneh-Shahri
authors.forename: M
authors.initials: M
authors.lastname: Mahmoudian