1644-P: Exercise and Caloric Restriction Exert Different Benefits on Metabolism and Mechanical Function of Skeletal Muscle in Aging Condition

Exercise and caloric restriction improve skeletal muscle metabolism. However, the benefits of exercise and caloric restriction on metabolism and mechanical function of skeletal muscle in aging condition have never been compared. Seven-week-old male Wistar rats (n = 24) were divided into 4 groups (n = 6 per group) to receive subcutaneous injection with either 1) normal saline solution as a vehicle for 28 weeks, 2) 150 mg/kg/day of D-galactose [D-gal] for 28 weeks to induce premature aging, 3) D-gal for 28 weeks and exercise for 16 weeks (week 13-28), and 4) D-gal for 28 weeks and 30% caloric restriction for 16 weeks (week 13-28). The 17-month-old male Wistar rats (n = 6) were subcutaneously injected with the vehicle for 28 weeks as the naturally aged control. At the end of week 28, whole-body substrate oxidation during vigorous physical activity, total walking distance, and fitness level were determined. Then, all rats were sacrificed to collect the tibialis anterior muscle for protein expression analyses and mass spectrometry-based metabolomics study. We found that skeletal muscle of D-gal successfully mimicked that of natural aging. Exercise and caloric restriction equally improved whole-body carbohydrate oxidation during vigorous physical activity, myogenesis, and amino acid metabolism in skeletal muscle. However, exercise was superior to caloric restriction in terms of improving fatty acid oxidation, oxidative phosphorylation, and mechanical function of skeletal muscle. Interestingly, caloric restriction decreased oxidative stress, whereas exercise increased oxidative stress in skeletal muscle. These findings suggested that the benefits of exercise and caloric restriction on metabolism and mechanical function of skeletal muscle in aging were different. Hence, either combined exercise and caloric restriction, exercise with antioxidant supplement, or caloric restriction with fatty acid oxidation enhancement is highly recommended. Disclosure C.Thonusin: None. P.Pantiya: None. W.Nawara: None. B.Arunsak: None. S.Sriwichaiin: None. N.Chattipakorn: None. S.C.Chattipakorn: None.