Exercise ameliorates high-fat diet-induced metabolic and vascular dysfunction, and increases adipocyte progenitor cell population in brown adipose tissue

A high-fat diet (HFD) is associated with adipose inflammation, which contributes to key components of metabolic syndrome, including obesity and insulin resistance. The increased visceral adipose tissue mass associated with obesity is the result of hyperplasia and hypertrophy of adipocytes. To investigate the effects of exercise on HFD-induced metabolic disorders, male C57BL/6 mice were divided into four groups: SED (sedentary)-ND (normal diet), EX (exercise)-ND, SED-HFD, and EX-HFD. Exercise was performed on a motorized treadmill at 15 m/min, 40 min/day, and 5 day/wk for 8 wk. Exercise resulted in a decrease in abdominal fat contents and inflammation, improvements in glucose tolerance and insulin resistance, and enhancement of vascular constriction and relaxation responses. Exercise with or without HFD increased putative brown adipocyte progenitor cells in brown adipose tissue compared with groups with the same diet, with an increase in brown adipocyte-specific gene expression in brown and white adipose tissue. Exercise training enhanced in vitro differentiation of the preadipocytes from brown adipose depots into brown adipocytes and enhanced the expression of uncoupling protein 1. These findings suggest that exercise ameliorates high-fat diet-induced metabolic disorders and vascular dysfunction, and increases adipose progenitor cell population in brown adipose tissue, which might thereby contribute to enhanced functional brown adipose.