Date Published: April 25, 2019
Publisher: Public Library of Science
Author(s): Anna Laura V. Américo, Cynthia R. Muller, Bruno Vecchiatto, Luiz Felipe Martucci, Miriam H. Fonseca-Alaniz, Fabiana S. Evangelista, Michael Bader.
We investigate the effects of aerobic exercise training (AET) on the thermogenic response, substrate metabolism and renin angiotensin system (RAS) in the subcutaneous white adipose tissue (SC-WAT) of mice fed cafeteria diet (CAF). Male C57BL/6J mice were assigned into groups CHOW-SED (chow diet, sedentary; n = 10), CHOW-TR (chow diet, trained; n = 10), CAF-SED (CAF, sedentary; n = 10) and CAF-TR (CAF, trained; n = 10). AET consisted in running sessions of 60 min at 60% of maximal speed, five days per week for eight weeks. The CAF-SED group showed higher body weight and adiposity, glucose intolerance and insulin resistance (IR), while AET prevented such damages in CAF-TR group. AET reduced the p-AKT/t-AKT ratio and increased ATGL expression in CHOW-TR and CAF-TR groups and increased t-HSL and p-HSL/t-HSL ratio in CAF-TR. AET prevented adipocyte hypertrophy in CAF-TR group and increased UCP-1 protein expression only in CHOW-TR. Serum ACE2 increased in CHOW-TR and CAF-TR groups, and Ang (1–7) increased in the CHOW-TR group. In the SC-WAT, CAF-TR group increased the expression of AT1, AT2 and Mas receptors, whereas CHOW-TR increased Ang (1–7) and Ang (1–7)/Ang II ratio in SC-WAT. No changes were observed in ACE and Ang II. Positive correlations were observed between UCP-1 and kITT (r = 0.6), between UCP-1 and Ang (1–7) concentration (r = 0.6), and between UCP-1 and Ang (1–7)/Ang II ratio (r = 0.7). In conclusion, the AET prevented obesity and IR, reduced insulin signaling proteins and increased lipolysis signaling proteins in the SC-WAT. In addition, the CAF diet precludes the AET-induced thermogenic response and the partial modulation of the RAS suggests that the protective effect of AET against obesity and IR could not be associated with SC-WAT RAS.
Aerobic exercise training (AET) has been widely used for the prevention and treatment of obesity, insulin resistance (IR) and type 2 diabetes (T2D) because it is able to improve mitochondrial function and fatty acid oxidation [1, 2], reduces body weight and adiposity [3, 4], improves insulin sensitivity and glucose uptake in the skeletal muscle . AET also prevents ectopic lipid accumulation [6, 7] and ameliorates inflammatory response in T2D patient .
The present study proposed to investigate the effects of AET on the thermogenic response, substrate metabolism and RAS in the WAT-SC of mice fed cafeteria diet. For this, we firstly tested the efficacy of the AET to promote aerobic adaptation through a maximal physical test after AET. According to the results it was observed the favorable adaptation to AET in both trained groups. This result corroborates previously studies published in the literature [3, 7, 50]. It is already known in the literature that the improvement in the physical performance of trained animals establishes a direct relation between the improvement of the aerobic capacity and reduction of the risk of cardiovascular and metabolic diseases [55, 56].
In conclusion, the AET prevented obesity and IR, reduced insulin signaling proteins and increased lipolysis signaling proteins in the SC-WAT. In addition, the CAF diet precludes the AET-induced thermogenic response and the partial modulation of the RAS suggests that the protective effect of AET against obesity and IR could not be associated with SC-WAT RAS.