Abstract Aging results in significant loss of mass and function of the skeletal muscle,
which negatively impacts the quality of life. In this study we investigated whether
aerobic exercise training has the potential to alter anabolic and catabolic pathways
in the skeletal muscle. Five and twenty eight month old rats were used in the study.
Aging resulted in decreased levels of follistatin/mTOR/Akt/Erk activation and increased
myostatin/Murf1/2, proteasome subunits, and protein ubiquitination levels. In addition,
TNF-α, reactive oxygen species (ROS), p53, and Bax levels were increased while Bcl-2
levels were decreased in the skeletal muscle of aged rats. Six weeks of exercise training
at 60% of VO2max reversed the age-associated activation of catabolic and apoptotic
pathways and increased anabolic signaling. The results suggest that the age-associated
loss of muscle mass and cachexia could be due to the orchestrated down-regulation
of anabolic and up-regulation of catabolic and pro-apoptotic processes. These metabolic
changes can be attenuated by exercise training.
