The effects of dietary cholesterol and resistance training on lean mass change and cholesterol metabolism in rat skeletal muscle
Resistance exercise (RE) training is a potent stimulus of muscle growth, and recent evidence suggests that cholesterol (CL) may augment this process. Moreover, CL may influence sterol regulatory element binding protein-2 (SREBP-2), which is the master regulator of cellular CL metabolism. In this study, 40 Sprague-Dawley rats were assigned to 1 of 6 groups: cage control (CC; n=5), CC + CL (CLCC; n=4), RE controls (REC; n=7), REC + CL (CLREC; n=8), RE (RE; n=8) and RE + CL (CLRE; n=8). RE/REC consisted of squat-like exercise. RE had weights added progressively from 80–410 g over 5 weeks. CL was supplemented in the chow with either 180 ppm (controls) or 1800 ppm (CL). Body composition was assessed before and after 5 weeks by dual energy x-ray absorptiometry while SREBP-2 was measured in quadriceps muscle via Western Blotting. SREBP-2 levels were significantly elevated for increasing levels of exercise (Table; P=0.04). Optimal muscle growth occurred without progressive weights added although CL rescued the deleterious effects in the RE group (Table). These preliminary data support the hypothesis that CL metabolism is associated with the response to RE training.
