1. Graduate Institute of Sports Science, College of Exercise and Health Sciences, National Taiwan Sport University, Taoyuan 33301, Taiwan;
2. Department of Hospitality Management, College of Agriculture, Tunghai University, Taichung 40704, Taiwan.
*These authors contributed equally to this work.
The protein deacetylase sirtuin 1 (SIRT1) and activate peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) pathway drives the muscular fiber-type switching, and can directly regulate the biophysiological functions of skeletal muscle. To investigate whether 12-week swimming exercise training modulates the SIRT1/PGC-1α pathway associated proteins expression in rats of different age. Male 3-month-old (3M), 12-month-old (12M) and 18-month-old (18M) Sprague-Dawley rats were used and assigned to sedentary control (C) or 12-week swimming exercise training (E) and divided into six groups: 3MC (n = 8), 12MC (n = 6), 18MC (n = 8), 3ME (n = 8), 12ME (n = 5) and 18ME (n = 6). Body weight, muscle weight, epididymal fat mass and muscle morphology were performed at the end of the experiment. The protein levels of SIRT1, PGC-1α, AMPK and FOXO3a in the gastrocnemius and soleus muscles were examined. The SIRT1, PGC-1α and AMPK levels in the gastrocnemius and soleus muscles were up-regulated in the three exercise training groups than three control groups. The FOXO3a level in the 12ME group significantly increased in the gastrocnemius muscles than 12MC group, but significantly decreased in the soleus muscles. In 3-, 12- and 18-month-old rats with and without exercise, there was a significant main effect of exercise on PGC-1α, AMPK and FOXO3a in the gastrocnemius muscles, and SIRT1, PGC-1α and AMPK in the soleus muscles. Our result suggests that swimming training can regulate the SIRT1/PGC-1α, AMPK and FOXO3a proteins expression of the soleus muscles in aged rats.
Keywords: exercise training, aging, skeletal muscle, SIRT1, PGC-1α.