Resveratrol did not alter blood pressure in rats with nitric oxide synthase-inhibited hypertension

Background: Inhibition of nitric oxide synthase (NOS) is a well-known experimental model of hypertension (HT). It was shown that oxidative stress contributes to the pathogenesis of HT. Resveratrol is a potent anti-oxidant that is found in red grapes, peanuts and red wine. It improves the NO response and increases endothelial NOS expression, which causes endothelium-dependent vasorelaxation as well as renal vasodilation. We aimed to explore the effects of resveratrol on blood pressure, the water-salt balance and sodium excretion as a reflection of renal function in NOS-inhibited rat models. Methods: Thirty-five male Sprague-Dawley rats (200-250 g) were used in this study. In order to obtain hypertension models, an NOS inhibitor, N-nitro-L-arginin (L-NNA) was used. The rats were randomly divided into five groups: controls (given water and 0.8% salty diet) and four groups [given L-NNA, resveratrol (RSV) eluent, RSV, and L-NNA + RSV]. Blood pressures were measured indirectly by the tail-cuff method on the first, seventh and 10th days. At the end of the study protocol (10th day), fluid balance, glomerular filtration rate, fractional sodium excretion, and blood and urine sodium and creatinine levels were measured. Results: At the end of the study protocol, blood pressures were higher in only the L-NNA group (117.8 +/- 3.5 vs 149.5 +/- 2.1 mmHg; p < 0.05), as expected. Additional applications of RSV with L-NNA could not prevent the increase in blood pressure (122.8 +/- 7.3 vs 155.4 +/- 4.4 mmHg; p < 0.05). There were no remarkable changes in water-salt balance and renal function with the application of resveratrol. Conclusion: Resveratrol was unable to prevent or reverse blood pressure increase in NOS-inhibited rats.