Physical exercise increases the expression of TNFα and GLUT 1 in muscle tissue of diabetes prone Psammomys obesus

IntroductionTumor necrosis factor-α (TNFα) is a major mediator of insulin resistance. On the other hand, it has been suggested that TNFα may facilitate glucose uptake through GLUT 1 expression. We recently found that physical exercise prevented the progression to type 2 diabetes mellitus in diabetes prone Psammomys obesus (sand rat).AimThe aim of the present study was to characterize the influence of physical exercise on the expression of TNFα, its receptor R1 and GLUT 1 in muscle tissue of this animal model.MethodsAnimals were assigned for 4 weeks to four groups: high-energy diet (HC), high-energy diet and exercise (HE), low-energy diet (LC), low-energy diet and exercise (LE). TNFα, R1 and GLUT 1 expression were analyzed using Western blot technique.ResultsNone of the animals in the HE group became diabetic while all the animals in the HC group became diabetic. TNFα, its receptor (R1) and GLUT 1 expressions were significantly higher in the two exercising groups (LE and HE) and significantly lower in the HC group compared to the control LC group.ConclusionsPhysical exercise augments the expression of TNFα, its receptor R1 and the glucose transporter GLUT 1 in muscle tissue. We suggest that this mechanism may improve glucose uptake through pathways parallel and unrelated to insulin signaling that may include MAPK and/or NO. These biochemical processes contribute to the beneficial effects of physical exercise on the prevention of type 2 diabetes mellitus.