Exercise training improves obesity-induced inflammatory signaling in rat brown adipose tissue

Chronic inflammation is considered as an etiology of obesity and type 2 diabetes. Brown adipose tissue (BAT) of obese animals shows increased inflammation. Regular exercise has anti-inflammatory effects; however, the effects of exercise training on BAT inflammation in obese animals remain unclear. Thus, this study aimed to investigate the effects of exercise training on inflammation-related signaling in the BAT of obese and diabetic rats. Male Otsuka Long-Evans Tokushima Fatty (OLETF) rats, an obese/diabetic rodent model, were randomly divided into either sedentary (n = 11) or exercise training (n = 8) groups. Long-Evans Tokushima Otsuka (LETO; n = 9) rats were used as the nondiabetic sedentary controls. Exercise training using a treadmill was conducted 4 days per week for 20 weeks, starting at 5 weeks old. As a result, exercise training attenuated the phosphorylation levels of p65 and mitogen-activated protein kinases in the BAT of OLETF rats, concurrently with the improvement of obesity and systemic glucose tolerance. Moreover, exercise training decreased oxidative stress and increased the antioxidant and anti-inflammatory protein levels in the BAT. Conversely, exercise training did not alter the expression levels of uncoupling protein-1 and oxidative phosphorylation-related proteins in the BAT, which were lower in the OLETF rats than the LETO rats. In conclusion, our data suggest that exercise training prevents the activation of inflammatory signaling in the BAT of obese/diabetic rats.