Efeito do extrato de Euterpe oleracea Mart. (Açaí) e do exercício físico sobre as alterações vasculares e de memória ocasionadas pelo envelhecimento

Abstract

The population aging has increased around the world. In Brazil, approximately 70% of the older people have a chronic disease. So, the treatment of chronic diseases in old age becomes a great challenge for public health. Lifestyle changes involving nutritional strategies and regular and moderate exercise training can have a protective effect against diseases caused by aging. The Açaí seed extract (ASE), rich in polyphenols, demonstrated vasodilating and antioxidant properties. Therefore, the purpose of the present study is to examine the effect of treatment with ASE (200mg/kg) and exercise training on vascular function, exercise performance, memory and learning in older animals. Male Wistar rats were divided into 5 groups: Young (3 months), Old (18 months), Old+ASE (18 months+ ASE), Old+Training (18 months + exercise training) and Old+Training+ASE (18 months + exercise training + ASE). The maximum treadmill stress test (MST) was developed according to Matsuura et al. 2010. Plasma glucose and lactate levels were examined at the end of each MST. The exercise training was performed on a treadmill (30 min/day; 5 days/week) for 4 weeks. Blood pressure was measured by tail plethysmography once a week. At the end of the experimental period, the step down avoidance test was performed to examine short-term and long-term memory. After euthanasia, we performed vascular reactivity in a mesenteric arterial bed (MAB) and aortic ring as well as we evaluated the expression of proteins involved for the production of nitric oxide in the aorta and LAM, proteins involved in mitochondrial biogenesis in the soleus muscle, and and key proteins for neural plasticity in hippocampus. The antioxidant defense and oxidative damage were also studied. The distance(m) and time (s) were increased (p≤0.05) in the Old+Training+ASE group compared to the Old+Training group. The weight (g) of young animals was lower than that old animals during the experimental period. The lactate (mmol/L) and blood glucose levels did not different between groups. The animals in the Young group showed a reduction (p≤0.05) in the vasoconstrictor response and increase (p≤0.05) in the vasodilator response compared to the Old group, both in MAB and in the aortic ring. The Old+Training and Old+ASE groups showed an increase (p≤0.05) in the vasodilator response in the aorta and a reduction (p≤0.05) in the vasoconstrictor response compared to the Old group, in addition to reducing (p≤0.05) blood pressure and damage oxidative in the aorta and hippocampus. The association of exercise training with ASE in Old animals also increased (p≤0.05) the vasodilation in MAB compared to the Old group and not only reduced (p≤0.05) blood pressure but also reversed the loss (p≤0.05 ) of performance in long-term aversive memory caused by aging. The synergism between ASE and exercise also increased the antioxidant defense (p<0.05) and the expression of mitochondrial biogenesis proteins in skeletal muscle. Based on the results presented, we demonstrate a positive interaction of aerobic training exercise with ASE on the aging process by improving blood pressure, vascular function, oxidative state, positively regulating key proteins of mitochondrial biogenesis in skeletal muscle, which should contribute to exercise tolerance in aging. We also observed the beneficial effect of the association of the extract with exercise training on cognitive decline, possibly due to the extract's vasodilating and antioxidant action.