Hydrogen Sulfide Improves the Endothelial Dysfunction in Renovascular Hypertensive Rats

Abstract

As a novel gasotransmitter, hydrogen sulfide (H2S) has vasodilating and antihypertensive effects in cardiovascular system. Thus, we hypothesized that H2S might have beneficial effects on thoracic endothelial function in two-kidney one-clip (2K1C) rats, a model of renovascular hypertension. Sodium hydrosulfide (NaHS, 56 μmol/kg/day) was administrated intra-peritoneally from the third day after the 2K1C operation. Along with the development of hypertension, the systolic blood pressure (SBP) was measured before the operation and each week thereafter. The oxidative stress was determined by measurement of malondialdehyde (MDA) concentration, superoxide dismutase (SOD) activity and protein expression of oxidative stress-related proteins (AT1R, NADPH oxidase subunits). Acetylcholine (ACh)-induced vasorelaxation and angiotensin II (Ang II)-induced vasocontraction were performed on isolated thoracic aorta. The SBP was significantly increased from the first week after operation, and was lowered by NaHS. NaHS supplementation ameliorated endothelial dysfunction. The protein expression of oxidative stress-related proteins were downregulated, while SOD activity upregulated. In conclusion, improvement of endothelial function is involved in the antihypertensive mechanism of H2S. The protective effect of H2S is attributable to suppression of vascular oxidative stress that involves inhibition of Ang II-AT1R action, downregulation of oxidases, as well as upregulation of antioxidant enzyme.