Estudo da influência do tecido adiposo perivascular nas alterações vasculares de ratos submetidos à dieta hiperlipídica: ações do extrato da Euterpe oleracea mart. (açaí) e do exercício físico

Abstract

Obesity is associated with the development of cardiovascular diseases (CVD). The morphofunctionality of the perivascular adipose tissue (PVAT) is impaired in obesity, which can influence the progress of CVD. Physical activity is recommended for the treatment of obesity, and the açaí seed extract (ASE) can prevent hypertension, body mass gain, and dyslipidemia in obesity model. Therefore, we sought to study the effects of treatment with ASE associated or not with physical exercise on physical performance, functional and structural vascular changes in Sprague Dawley (SD) rats submitted to a high-fat diet, as well as the influence of TAPV on these alterations, oxidative stress and inflammation in TAPV and aorta. For this, 75 male SD rats, 4 weeks old, were separated into groups: CT (standard diet), HF (55% lipid diet), HF+A (200mg/Kg/day of ASE), HF+TR, (physical training) and HF+TA. First, the diet was administered in isolation for 10 weeks and, after that, for another 6 weeks, concurrently with ASE treatment and exercise (moderate intensity, 5 days/week, 30 minutes/day). An exercise test (ET) was performed at the 10th, 13th, and 16th weeks. Lactate was measured after the 1st and 3rd ET. Body weight and blood pressure were measured weekly. During the 10th and 16th weeks, nuclear magnetic resonance was performed. Glucose was measured at the beginning of the 1st week and at the end of the 10th and 16th. At the end of the 16th, an oral glucose tolerance test was performed. After that, the animals were euthanized, and the aorta with and without PVAT was isolated for vascular reactivity assays in response to acetylcholine (ACh), sodium nitroprusside, and phenylephrine (FE). The lipid profile and leptin were measured in plasma. In the aorta and TAPV we were evaluated: morphology and vascular remodeling by light microscopy, activity of antioxidant enzymes (SOD, CAT and GPx) and nitrite levels by spectrophotometry, peNOS, NOX4, 8-isoprostane, IL-6 and TNF-α by immunohistochemistry, nitric oxide and peroxide levels by immunofluorescence. ASE and exercise, isolated, were effective in preventing weight gain, body fat mass, hypertension and alterations in the structure of the aorta. We observed in HF animals an alteration in the morphology of the TAPV and its modulation on the vasodilatory response to ACh and vasoconstrictor response to FE, as well as a positive correlation between the TAPV and aorta about alterations in markers of oxidative damage, antioxidant defense and inflammatory markers. However, ASE was higher to exercise in preventing phenotypic and functional changes in PVAT, restoring the positive modulation of perivascular adipose tissue, in addition to reducing oxidative stress and inflammation, both in the aorta and in PVAT. However, only the association of exercise with ASE promoted an additional improvement in the lipid profile. Therefore, these findings suggest a great potential of the extract associated with exercise, in the treatment of obesity and functional and structural vascular changes associated, with a positive impact on blood pressure.