SWIMMING TRAINING IMPROVES BROWN-ADIPOSE-TISSUE ACTIVITY IN YOUNG ANDOLD MICE

The impairment of brown adipose tissue (BAT) thermogenic activity with aging has been well documented. The current study investigated the ef fect of swimming training on BAT activity in 2-month-old (young) and 2 6-month-old (old) male mice. The trained mice underwent a 6-week swimm ing program (1 h/day, 5 days/week) in water at 35-36 degrees C, Compar ed with young sedentary mice, the BAT-to-body mass ratio was markedly smaller in old sedentary mice, accompanied by the decreased amount of protein, whereas there was no significant difference in uncoupling pro tein (UCP) content, UCP mRNA expression, or guanosine 5'-diphosphate ( GDP) binding (an index of UCP activity) between young and old mice. Me anwhile, the swimming training definitely increased BAT mass and its p rotein content in both the young and old mice, suggesting hypertrophy and hyperplasia. In addition, after the swimming training, the amounts of protein, UCP antigen, and GDP binding in the mitochondria recovere d from BAT of both mice increased significantly as compared with the r espective sedentary groups, while the expression of UCP mRNA did not v ary substantially. These findings suggest that, irrespective of age, s wimming training enhances the thermogenic activity and capacity in BAT of mice.