Efeitos da adrenodemedulação e do treinamento físico no desenvolvimento da obesidade induzida por dieta rica em carboidratos em ratos

Abstract

The present study aimed to: 1) Verify if the adrenaldemedullation procedure contributes to potentiate the effect of high-sugar diet during the development of obesity; 2) Compare the effects of chronic exercise, initiated at 35 days of life on blood glucose and total cholesterol of obese and controls sham or adrenaldemedullated rats; 3) Evaluate if the lack of adrenal catecholamine influences physical performance. Animals were distributed into 2 groups of obese and lean rats, and then divided into 4 subgroups sham and adrenaldemedullated, exercised or sedentary. At 21 days old, obesity was induced by high-sugar diet and, adrenaldemedullation was performed at 22 days of life. Exercise protocol performed was treadmill running with incremental intensity and volume, 5 times a week during 8 weeks. Animals were euthanized at 92 days and it were evaluated food intake, body weight, Lee index, retroperitoneal and perigonadal fat pads, total adrenal catecholamine content, performance test, blood glucose and total cholesterol. It was used three-way ANOVA to test the effects of diet, exercise training and adrenaldemedullation on dependent variables followed by one-way ANOVA to compare the difference among variables. High-sugar diet obese groups presented higher values of food intake than control animals, resulting in an increase of 25 % on body weight and higher Lee Index independent of adrenaldemedullation. Moreover, retroperitoneal and perigonadal fat pad, blood glucose and total cholesterol values were enhanced in high-sugar obese animals and potentiated by adrenaldemedullation. On the other hand, physical training was able to attenuate those parameters. Adrenaldemedullated rats, control and obese ones, showed 100 times lower adrenal catecholamine than sham groups, which demonstrates the effectiveness of the surgery. Therefore, the variable physical performance does not appear to be influenced by the presence of adrenal catecholamine. Moreover, we suggest that the high-carbohydrate diet when associated to the absence of adrenal catecholamines promotes greater adiposity in rats. Physical training reduces body composition, blood glucose and total cholesterol levels regardless of diet. However, adrenaldemedullation seems to prevent a more pronounced reduction of blood glucose and cholesterol on trained rats.