Ginsenoside Rg1 attenuates diabetic vascular endothelial dysfunction by inhibiting the calpain-1/ROS/PKC-β axis

Aims: Vascular endothelial dysfunction (VED) is the onset event of cardiovascular complications in type 2 dia-betes mellitus. Ginsenoside Rg1 (Rg1) can improve the cardiovascular system, but its mechanism in diabetic vascular endothelial dysfunction has received little attention.Main methods: Male calpain-1-knockout and wild-type C57BL/6 J mice were intraperitoneally injected with streptozotocin and treated with Rg1 (10 and 20 mg/kg) for 8 weeks. Human aortic endothelial cells (HAECs) were incubated with high glucose (HG) and were pretreated with Rg1 (10, 20 & mu;M), MDL-28170 (calpain-1 in-hibitor), LY-333531 (PKC-& beta; inhibitor), NAC (ROS inhibitor) and calpain-1 overexpression. Then, factors related to mitochondrial dysfunction, oxidative stress and VED were measured.Key findings: The administration of Rg1 and calpain-1 knockout ameliorated diabetic mitochondrial dysfunction, oxidative stress and VED and inhibited the calpain-1/ROS/PKC-& beta; axis. LY-333531 and NAC treatment restored destructive endothelium-dependent vasodilation in mice with diabetes, while pyrogallol (ROS agonist), PMA (PKC-& beta; agonist) or L-NAME (eNOS inhibitor) treatment abrogated the protective effect of Rg1 against diabetic endothelial dysfunction. The administration of Rg1, MDL-28170, LY-333531 and NAC improved mitochondrial dysfunction, oxidative stress and VED, whereas the overexpression of calpain-1 amplified mitochondrial dysfunction, oxidative stress and VED and further upregulated the expression of PKC-& beta; in HAECs exposed to HG. Overexpression of calpain-1 abrogated the protective effect of Rg1 against HG-induced oxidative stress and VED.Significance: These findings reveal that Rg1 can protect against VED by suppressing the calpain-1/ROS/PKC-& beta; axis and alleviating the development of mitochondrial dysfunction and oxidative stress.