Efeito do extrato de Euterpe oleracea Mart.(Açaí) sobre a disfunção endotelial, estresse oxidativo e alterações vasculares e renais associados à hipertensão renovascular dois rins, 1 clip (2R,1C)

Abstract

Studies show that açai is rich in polyphenols and a diet rich in polyphenols may be involved in protection against cardiovascular risk. The aim this study was assessed the effect of chronic treatment of hypertensive animals 2K,1C with hydroalcoholic extract the stone of açaí (ASE) on the development of hypertension and endothelial dysfunction, oxisative stress and renal and vascular changes. Male Wistar rats used to obtain the renovascular hypertension 2K,1C and control rats 2K (sham) were only subjected to laparotomy, were treated daily with vehicle or ASE (200mg/Kg/dia) for 40 days, and had a systolic blood pressure (SBP) measured plethysmography by the tail. The vasodilatory effects of acetylcholine (ACh) and nitroglycerin (NG) were studied in mesenteric arterial bed (LAM) perfused and pre-contracted with norepinephrine. The activity of enzymes SOD, CAT, GPx, malondialdehyde (MDA) levels, carbonyl protein and levels of nitrite were measured by spectrophotometry. The expressions of pro and antioxidant enzymes were assessed by western blot. The activity of MMP-2 was analyzed by zymography. The serum creatinine levels were assessed using a kit by spectrophotometry. The vascular and renal changes were evaluated by light microscopy. The SBP was higher in 2K,1C animals, and treatment with ASE prevent the development of hypertension. The effect of reduced vasodilator ACh in 2K,1C animals was recovered by ASE. The vasodilator effect of NG was not different between groups. Oxidative damage assessed by lipid peroxidation and protein carbonylation was greater in 2K,1C animals, and reduced by treatment with ASE. The activities of SOD, CAT and GPx were lower in samples of mesentery, plasma, kidney and heart of 2K,1C animals and ASE treatment increased these activities. The production of NO was lower in plasma, mesentery, kidney of 2K,1C animals and treatment with ASE increased the production of NO only in the kidney and mesentery of these animals. Expression of SOD-1, 2, TIMP-1 and eNOS was lower in 2K,1C animals and ASE treatment increased the expression of these enzymes. The expression for NOX-4, MMP-2 and MMP-2 activity were increased in the 2K,1C animals and ASE treatment reduced expression of these enzymes and activity of MMP-2. 2K,1C animals showed an increase in medial thickness of aorta and mesenteric artery and an increase in the ratio media/lumen of the aorta, and these changes were prevented by ASE. Serum levels of creatinine increased in 2K,1C animals were reduced by ASE. The renal morphological changes in 2K,1C animals were prevented by ASE. Therefore, treatment with ASE prevents the development of hypertension, improves endothelial dysfunction and prevents the renal and vascular changes in 2K,1C rats. The reduction in antioxidant activity and increased lipid peroxidation and protein carbonyls suggest the involvement of a mechanism of impaired antioxidant defense and increased oxidative damage, which was reversed by ASE.