Abstract

PURPOSE: To evaluate the effects of chronic leucine supplementation combined with aerobic training on exercise performance, food intake and hippocampal signaling of male Wistar rats. METHODS: Eighteen male wistar rats (∼400 g) were randomly divided into 4 experimental groups (n = 06/group): control sedentary (CS), leucine sedentary (LS); exercise placebo (EP); and exercise leucine (EL). During 12 weeks, exercised groups were submitted to aerobic training (treadmill) at 60% VO2 máx and leucine-supplemented groups received 0.135 g·kg·d-2 of leucine or placebo (alanine) through gavage. Food intake was registered throughout the experiment. At baseline and every 15 days, all the animals were submitted to maximal aerobic capacity test to correct the exercise intensity. At the end of the experiment, animals were euthanized and brain tissue was immediately removed and frozen for Western Blotting analyses. Protein expression of Akt, mTOR, p70S6k, p38 MAPK and SAP/JNK were performed and quantified through Image J software. The dependent variables were tested by one-way ANOVA with post hoc test of Tukey. The significance level was set at p < 0.05. RESULTS: At the end of the experiment, EP group presented higher aerobic capacity when compared to both CS and LS groups (p < 0.01). However, EL presented higher aerobic capacity when compared to the EP group (p < 0.001). Food intake (area under the curve) was significantly decreased in EL group when compared to the others (p < 0.01). At the end of the experimental protocol, EP group present significant higher content of total Akt (p < 0.05), total mTOR (p < 0.001) and decreased total SAP/JNK (p < 0.01) when compared to the CS group. EL group presented significant higher total mTOR content when compared to the LS group (p < 0.001). LS group presented significantly decreased p38 MAPK (p < 0.05) and SAP/JNK (p < 0.01) content when compared with the CS group. Total p70S6k content was not different among groups (p > 0.05). CONCLUSION: Leucine supplementation combined with aerobic training increase exercise performance and decrease food intake in rats. The decrease in food intake was associated with modified expression of Akt/mTOR pathway and of some inflammatory proteins in the brain.