Effect of Combined Exercise Versus Aerobic-Only Training on Skeletal Muscle Lipid Metabolism in a Rodent Model of Type 1 Diabetes

Abnormal skeletal muscle lipid metabolism is associated with insulin resistance in people with type 1 diabetes. Although lipid metabolism is restored with aerobic exercise training, the risk for postexercise hypoglycemia is increased with this modality. Integrating resistance and aerobic exercise is associated with reduced hypoglycemic risk; however, the effects of this exercise modality on lipid metabolism and insulin resistance remain unknown. We compared the effects of combined (aerobic + resistance) versus aerobic exercise training on oxidative capacity and muscle lipid metabolism in a rat model of type 1 diabetes. Male Sprague-Dawley rats were divided into 4 groups: sedentary control (C), sedentary control + diabetes (CD), diabetes + high-intensity aerobic exercise (DAE) and diabetes + combined aerobic and resistance exercise (DARE). Following diabetes induction (20 mg/kg streptozotocin over five days), DAE rats ran for 12 weeks (5 days/week for 1 hour) on a motorized treadmill (27 m/min at a 6-degree grade), and DARE rats alternated daily between running and incremental weighted ladder climbing. After training, DAE showed reduced muscle CD36 protein content and lipid content compared to CD (p≤0.05). DAE rats also had significantly increased citrate synthase (CS) activity compared to CD (p≤0.05). DARE rats showed reduced CD36 protein content compared to CD and increased CS activity compared to CD and DAE rats (p≤0.05). DARE rats demonstrated increased skeletal muscle lipid staining, elevated lipin-1 protein content and insulin sensitivity (p≤0.05). Integration of aerobic and resistance exercise may exert a synergistic effect, producing adaptations characteristic of the “athlete's paradox,” including increased capacity to store and oxidize lipids. L'anomalie du métabolisme lipidique des muscles squelettiques est associée à l'insulinorésistance chez les personnes atteintes du diabète de type 1. Bien que l'exercice aérobique restaure le métabolisme des lipides, cette modalité d'entraînement augmente le risque d'hypoglycémie après l'exercice. L'intégration de l'exercice contre résistance et de l'exercice aérobique est associée à la diminution du risque d'hypoglycémie. Toutefois, on ignore les effets de cette modalité d'entraînement sur le métabolisme des lipides et l'insulinorésistance. Nous avons comparé les effets de l'entraînement combiné (en aérobie+en résistance) par rapport à l'exercice aérobique sur la capacité oxydante et le métabolisme lipidique