L-Carnitine supplementation increases expression of PPAR-gamma and glucose transporters in skeletal muscle of chronically and acutely exercised rats

摘要

In this study, the effects of L-Carnitine supplementation on the lipid peroxidation and expression of PPAR-gamma and glucose transporters in the liver and muscles of chronically and acutely exercised rats were investigated. A total of 42 male Wistar Albino rats (8-week-old) were divided into six groups as follows: Control, L-Carnitine, Chronic Exercise (CE), Chronic Exercise + L-Carnitine, Acute Exercise (AE) and L-Carnitine + Acute Exercise. Chronic exercise consists of 30 m/min, 30 min/day, and 5 days/week for 6 weeks. Rats in the acute exercise groups were run on the treadmill at 30 m/min until exhaustion. L-Carnitine was given at the level of 300 mg per kilogram of diet for 6 weeks. There was no significant difference in the levels of serum ALT, AST, urea, creatinine and glucose levels between the exercise and L-Carnitine groups (P 0.05). Cholesterol and triglyceride levels decreased by L-carnitine supplementation and chronic exercise in control groups but increased in the AE groups compared to the control group without reinforcement (P 0.05). Serum, muscle, heart, and liver malondialdehyde (MDA) concentrations were lower in CE and higher in the AE groups (P 0.001). However, L-Carnitine supplementation reduced MDA levels (P 0.05). Liver and muscle PPAR-gamma, liver GLUT-2 and muscle GLUT-4 mRNA expressions were lower in AE group than in all other groups (P 0.001). Both chronic exercise and supplemental L-Carnitine increased liver and muscle PPAR-gamma, GLUT-2 and GLUT-4 mRNA expression (P 0.05). As a result, although acute exercise increased oxidative stress, chronic exercise reduced oxidative stress by lowering lipid peroxidation level. L-Carnitine supplementation decreased oxidative stress and improved glucose and lipid metabolism by regulation of PPAR-gamma, GLUT-2 and GLUT-4 mRNA expression in rats.