ENDURANCE TRAINING INCREASES HEAT SHOCK PROTEIN IN THE SKELETAL MUSCLE OF YOUNG AND OLD RATS

Abstract

1645 The purpose of this study was to examine the effects of aging and endurance exercise training on the heat shock protein (HSP) of skeletal muscle in young and old rats. Young (6mon) and old (22mon) female Fisher 344 rats were assigned to either a sedentary control or an endurance exercise training group (N=6 per group). Rats in both training groups completed a treadmill exercise program (@ 75% VO2max, 60 min/day, 5 days/wk) for 10 weeks. Upon completion of the training program, the soleus (SOL), plantaris (PL), extensor digitorum longus(EDL), and the red (RG) and white portions (WG) of the gastroenemius muscles were excised, and frozen for subsequent biochemical analysis. Skeletal muscle proteins were separated by SDS-PAGE and immunoblotted for HSP72. No differences (p>0.05) existed in skeletal muscle HSP72 levels between young controls and old controls. Compared to age-matched controls, exercise training elevated (p<0.05) skeletal muscle HSP72 in both young (SOL 122%, PL 194%, EDL 300%, RG 144%. WG 343%) and old animals (SOL 115%, PL 173%, EDL 281%, RG 138%, WG 250%). These data demonstrate that although endurance training enhances the expression of HSP72 in skeletal muscle of both young and old rats, the increase in HSP72 is comparatively less in old animals.