Efeito do extrato de Euterpe oleracea Mart. (Açaí) e do exercício físico sobre as alterações ocasionadas pelo diabetes tipo 2 induzido pela estreptozotocina e pela dieta hiperlipídica em ratos Wistar

Abstract

The type 2 diabetes mellitus (DM2) is one of the most prevalent diseases of our time. The central metabolic condition in this disease are disorders in glucose and lipid metabolism. Literature data suggest that a diet rich in polyphenols may be involved in protection against cardiometabolic risk. Other studies show that açaí fruit of Euterpe oleracea Mart., is rich in polyphenols and that physical training has received increasing recognition as a landmark in the prevention and treatment of DM2. Thus, the aim of this study was to expand our knowledge of the mechanisms involved in the beneficial effects of treatment with hydroalcoholic extract of the seed of açaí (ASE) on the physiological, metabolic, molecular and morphological changes associated with experimental model of DM2, and assess whether the physical exercise amplifies the effects of ASE. Two groups of Wistar rats (180-200 g) were fed experimental diets: control (10% fat) and high fat (HF) diet (55% fat) for 5 weeks. In the third week, HF group received an intraperitoneal injection of streptozotocin (35 mg kg-1), that increased blood glucose levels to more than 250/100 mL. The animals received control diet, ASE (200 mg/kg-1) by intragastric gavage and training on a treadmill for a period of four weeks, and were divided into eight groups: sedentary control and training (SC and TC) sedentary control and training treated with ASE (SCA and TCA), sedentary diabetic and training (SD and TD) and sedentary diabetic and training treated with ASE (SDA and TDA). We evaluated the body weight, parameters of physical activity, blood glucose, insulin, insulin resistance, vascular reactivity, pro-inflammatory cytokines, protein profile of insulin signaling cascade in epididymal adipose tissue (EAT) and skeletal muscle, protein profile of proteins associated with lipid synthesis and secretion in the liver oxidative damage, antioxidant enzyme activity, levels of nitrite, hepatic lipid accumulation, glycogen content and liver histology in diabetic animals. Treatment with ASE increased the distance traveled and the duration of physical activity during the stress test in TCA and TDA groups. Blood glucose, insulin, insulin resistance, serum levels of TNF-α, pJNK expression in EAT, the reactivity of mesenteric arteries with norepinephrine, endothelial dysfunction, MDA levels and protein carbonylation, serum lipid profile and liver cholesterol and triglycerides, the expression of AMPK, FAS, HMG CoA R, SREBP-1c and MTP in liver, and hepatic steatosis were reduced by treatment with ASE and physical exercise in diabetic animals. Treatment with ASE and exercise training increased the functionality of pancreatic beta cells (HOMA-B), HDL cholesterol levels, enzymatic antioxidant activity (SOD, CAT and GPX), nitrite levels, the expression of pIRS- 1, GLUT-4 and adiponectin in EAT and IR in skeletal muscle tissue, liver glycogen content and the expression of pAMPK, pACC and ABCG8 in the liver of diabetic animals. Treatment with ASE promotes beneficial effects on the changes caused by DM2. They also demonstrate that the association of physical exercise with the treatment amplifies the effects of ASE in many of the parameters studied. The antihyperglycemic action, the antioxidant and anti-inflammatory properties induced by ASE must contribute to the therapeutic potential of the extract.