Effect of Endurance Exercise and/or Diet Restriction on Mitochondrial Bioenergetics Function in Skeletal Muscle of Diabetic Male Albino Rats
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- Category: Vol. 81, December 2013
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Effect of Endurance Exercise and/or Diet Restriction on Mitochondrial Bioenergetics Function in Skeletal Muscle of Diabetic Male Albino Rats, NASHWA ELTABLAWY and EMAN F. KHALEEL
Abstract
Reduced mitochondrial capacity in skeletal muscle occurs in type 1 diabetic patient and in those at increased risk for this disorder, but the extent to which mitochondrial dysfunction in type 1 diabetic patients is remediable by physical activity and/or diet restriction intervention is uncertain. The aims of our study were to assess the effect of diet restriction and or endurance training on: 1- Expression of Peroxisome prolifer-ator-activated receptor gamma coactivator-1 alpha (PGC-1a) the major transcriptional coactivator regulating the expression of the oxidative phosphorylation (OXPHOS) gene, estrogen related receptor alpha (ERRa) and mitofusin2, 2- Expression of genes of mitochondrial enzymes involved in mitochondrial oxidative metabolism, 3- Lipid peroxidation as measured by (malondialdehyde) MDA and 4- Glucose metabolism.
Material and Methods: In this study six groups, 8 rats for each, were included: A sedentary fed ad libitum group, a trained fed ad libitum group, a diabetic sedentary fed ad libitum group, a diabetic trained group, a diabetic diet restricted group, and a diabetic trained-diet restricted group. For each group the following parameters were measured: 1- Serum glucose, serum insulin, 2- Glycogen, MDA level in gastroc-nemius muscle and 3- Gene expression by real time PCR for PGC-1a, ERRa, Mitofusin2, GLUT4, carnitine palmitoyl-transferase-1 (CPT-1) and citrate synthase.
Results: Our results showed that streptozotocin (STZ) induced diabetic rats had significant increase in glucose level and significant decrease in insulin level. Endurance training or diet restriction caused significant decrease in glucose level, while combination of diet restriction and endurance exercise synergistically caused significant decrease in comparison to diet restriction alone but still significantly higher than the normal level in the control rats. There was significant increase in MDA content of gastrocnemius muscles of STZ-induced diabetic rats which significantly decreased by diet restriction, more decreased by endurance exercise, combination of diet restriction and endurance exercise synergistically caused more decrease to the normal level as normal control rats. Glycogen content of gastrocnemius muscle of STZ-induced diabetic rats was decreased significantly which it was increased sig-nificantly by endurance exercise when compared to diabetic rats. Also our results showed significant decrease in mRNA o PGC-1a, ERRa, Mitofusin2, GLUT4, CPT-1, citrate synthase in gastrocnemius muscles STZ-induced diabetic rats in comparison to normal control rats. Diet restriction caused insignificant increase in PGC-1a, ERRa, mitofusin2, GLUT4, CPT-1. Endurance exercise in STZ-induced diabetic rats caused significant increased in gene expression of PGC-1a, ERRa, mitofusin2, GLUT4, CPT-1 and insignificant increased in citrate synthase. Combining effect of Diet restriction and endurance training caused insignificant increased in PGC-1a, Mitofusin2, GLUT4, CPT-1, citrate synthase in comparison to exercise alone.
Conclusion: Diet restriction and/or endurance training in diabetic rats induces mitochondrial bioenergetics in skeletal muscle, and enhances mitochondrial function and improve glucose metabolism by skeletal muscle possibly due to increase PGC-1a and ERRa. Therefore represent a key strategy in the prevention and treatment of type 1 diabetes and in those at increased risk for this disorder.