Dioscin Attenuates Myocardial Damages in Diabetic Rats maybe by Regulating NO-sGC-cGMP-PKG Pathway

PURPOSE: The objective of this research was to explore the effect of dioscin on myocardium in streptozotocin (STZ)-induced diabetic rats and the underlying mechanisms. METHODS: Diabetic rat model was established by a single intravenous injection of streptozocin (STZ). The rats were divided into 5 groups: control group, control+dioscin group, model group (diabetes), DDL group (diabetic rats treated with 100 μg/kg/day dioscin) and DDH group (diabetic rats treated with 200 μg/kg/day dioscin). Each group was continuously intervened for 6 weeks. Hemodynamic parameters were detected and pathological alterations of myocardium were observed by hematoxylin-eosin (HE) staining. Inflammatory response and related proteins in the NO-sGC-cGMP-PKG pathway were detected by western blot. RESULTS: Dioscin treatment can increase ejection fraction (EF) and decrease left ventricular end-diastolic pressure (LVEDP) as well as time constant of left ventricular pressure decay (Tau) parameters in diabetic rats, suggesting the improvement of left ventricular function. By histopathology observation, we found that dioscin treatment can also improve myocardial histological lesions caused by diabetes. In addition, the levels of inflammatory cytokines TGF-β1, TNF-α and IL-1β of the model group were remarkably higher than those in the control group (p<0.01), while after being treated with dioscin these cytokines were obviously decreased (p<0.05). The levels of PDE-5, PKG and p-VASP in the diabetic rats were significantly declined after being treated by dioscin in a dose-dependent manner (p<0.05). CONCLUSION: Dioscin may prevent the myocardial injury in diabetic rats by up-regulating NO-sGC-cGMP-PKG pathway.