High-intensity resistance training attenuates dexamethasone-induced muscle atrophy

ABSTRACT Introduction In this study we investigated the effects of high‐intensity resistance training (RT) on dexamethasone (DEX)‐induced muscle atrophy in flexor hallucis longus (FHL), tibialis anterior (TA), and soleus (SOL) muscles. Methods: Rats underwent either high‐intensity RT or were kept sedentary. In the last 10 days they received either DEX (0.5 mg/kg/day, intraperitoneally) or saline. Results: DEX reduced body weight (−21%), food intake (−28%), FHL and TA muscle mass (−20% and −18%, respectively), and increased muscle‐specific ring finger 1 (MuRF‐1) protein level (+37% and +45.5%). RT attenuated FHL muscle atrophy through a combination of low increase in MuRF‐1 protein level (−3.5%) and significant increases in mammalian target of rapamycin (mTOR) (+63%) and p70S6K (+46% and +49% for control and DEX, respectively) protein levels. Conclusion: RT attenuated DEX‐induced muscle atrophy through a combination of increases in mTOR and p70S6K protein levels and a low increase in MuRF‐1 protein level. Muscle Nerve 53: 779–788, 2016