Endothelial relaxation is disturbed by oxidative stress in the diabetic rat heart: influence of tocopherol as antioxidant.

摘要: Increased oxidative stress has been suggested to contribute disturbances in the regulation of coronary flow and increased cardiac risk diabetes mellitus. Using isolated perfused heart streptozotocin-diabetic rats our study shows that basal maximal (tested by infusion sodium nitroprusside) are not altered diabetes, but 5-hydroxytryptamine (5-HT) stimulated endothelium-dependent increase becomes progressively impaired. This defect vasodilatation was prevented perfusion hearts with Superoxide dismutase pretreatment diabetic tocopherol-acetate. Morphological studies also revealed tocopherol-acetate cardioprotective, largely severe alterations myocardial structure typically observed after a duration 3 months; deterioration fragmentation myofilament bundles were seen less, numbers areas focal necrosis contraction bands clearly reduced. In contrast untreated autonomic nerve fibers detected catecholamine fluorescence running parallel tocopherol-treated rats, amount catecholamines different from healthy control rats. Trichrome staining immunohistochemical collagen I III showed dramatic number size deposits at precapillary locations which significantly reduced anti-oxidative treatment. These findings demonstrate may only play major role impairment flow, development perivascular fibrosis changes nerves contractile system myocardium.