Efeitos agudos e crônicos do exercício físico e da suplementação de flavanóis do cacau (Theobroma cacao) sobre o desempenho físico, o metabolismo e mediadores inflamatórios em ratos resistentes à insulina

Abstract

Type 2 diabetes mellitus (DM2) is a multifactorial disease characterized by chronic hyperglycemia. The consumption of hypercaloric diets associated with a sedentary lifestyle has been responsible to increase the prevalence of obesity and DM2 in the world population. Although the consumption of cocoa flavanols (CF) is associated with several health benefits, its combined effects with aerobic exercise (EXE) in conditions of insulin resistance (IR) are still unknown. The objective this thesis was to verify the acute and chronic effects of EXE and CF supplementation on aerobic performance, metabolism and inflammatory markers in IR rats. The studies were approved by the Ethics Committee on the Use of Animals (CEUAUFMG, protocol No. 110/2016). Male Wistar rats (250 ± 10g) were submitted an insulin resistance induction protocol through a high-fat diet and a high-fructose beverage in combination for 30 days, control rats (CON) remained on standard rodent diet for the same period of time. In study 1, after the induction of IR, the CON and IR rats were supplemented with CF (45mg.kg-1 of body mass) or placebo solution (PLA) and submitted to running on a treadmill (60% VO2peak) or remained at rest (REST) for 30 minutes. The rats were euthanized 30 minutes after the experimental session. In study 2, the intervention with PLA or CF combined with the REST or EXE in the IR rats was performed once a day, five days a week for eight weeks. The rats were euthanized 48h after the last 6-hour fasting intervention session. Acute CF supplementation attenuated hyperglycemia after submaximal aerobic exercise promoting additive effects to that of EXE on the phosphorylation of Akt protein in the liver of IR mice. EXE and CF also increased phosphorylation of the AMPK protein in the liver and skeletal muscle, reduced the expression of TRB3 and increased the expression of CPT-1α (p<0.001). Chronically, CF supplementation and EXE per se improved the condition of glucose intolerance and the lipid profile, reduced the concentrations of leptin, glucose, insulin and HOMA index (p<0.001 and p<0.001) and improved the inflammatory millieu in tissues studied. In addition, when both interventions were combined, the increase in GLUT4 in the skeletal muscle was greater when compared to the interventions per se. Therefore the present thesis demonstrated the efficacy of EXE and CF in improving key factors in the treatment and prevention of IR, suggesting that the combination of both interventions can effectively contribute to the reduction of metabolic complications resulting from DM2.