Avaliação do tratamento com extrato da Euterpe oleracea Mart. e do exercício físico regular na resposta vascular e no perfil oxidativo de ratos espontaneamente hipertensos

Abstract

Hypertension is the most important risk factor for the development of cardiovascular diseases. The regular practice of physical activity is a non-pharmacological treatment and the açaí seed extract (ASE) with antihypertensive, antioxidant properties and improves physical performance. Therefore, the aim of the present work was evaluate the effects of treatment with ASE and moderate physical exercise on the vascular function in spontaneously hypertensive rats (SHR) and associate it with the oxidative state and physical performance. For this, it was used 10 wistar rats (CONTROL) and 40 SHR divided into SHR, SHR+ASE, SHR+TR (training) and SHR+TR+ASE. The TR occurs for 8 weeks, 5 times a week, for 30 minutes, with an intensity of 50% of the maximum speed reached during the exercise test that was performed before the beginning, in the middle and at the end of the TR. The ASE (200mg/kg/day/) were administered by intragastric gavage for 8 weeks. Body weight and artery pressure were measured weekly. Serum lactate and glucose levels were measured before the beginning and at the end of the experimental protocol. The oral glucose tolerance test (OGTT) was also performed. At the end, the animals were anesthetized and the mesenteric arterial bed and aorta were removed for vascular reactivity tests in response to acetylcholine (ACh) and noradrenaline (NE). The plasma and aorta were separated for analysis of lipid peroxidation markers, antioxidant enzymes and nitrite level. The expression of peNOS (Ser1177), Nrf2, Keap1, NOX4 proteins were evaluated in aorta. Morphological and immunohistochemical analysis of 8-isoprostane were performed in aorta fixed in formaldehyde. The treatment with ASE reduced body weight, with no further change by TR. The increased glycemia in SHR was not altered by ASE or TR, as well as there was no difference in OGTT between the groups. The ASE increased lactate levels at the end of 8 weeks. TR promotes an improvement in performance and treatment with ASE promotes an additional improvement in time (14%) and distance (32%). ASE reduced BP, improved vascular response, reduced aortic wall thickness and increased nitrite levels, improving vascular function improvement. In addition, it reduced oxidative stress markers and increased the activity of antioxidant enzymes. There was no difference in the expression of Nrf2, Keap1 and NOX4 proteins. The treatment with ASE promoted an additional gain in the performance of the animals submitted to training and maintained the acquired performance. This beneficial effect of the extract can be attributed in part to the reduction of BP and the improved vascular function, which was not promoted by training alone, associated with reduction of oxidative stress, resulting in the improvement of endothelial dysfunction commonly observed in hypertension.