Effects Of Endurance Training On The Activities Of P38 Mitogen-activated Protein Kinase (MAPK) Pathways In Skeletal Muscle Of Diabetic Rats

Objective: To determine the effects of different intensities of endurance training on the activation of p38 mitogen-activated protein kinase (MARK) pathways in skeletal muscle of diabetic rats.Method: Thirty six male 12-week-old Sprague-Dawley rats weighting 250-300g were modeled for diabetes by injection of streptozotocin at a dose of 55mg/kg. Then diabetic rats (blood glucose over 15mmol/l) were randomly divided into six groups: low-intensity training (E|, n=6), high-intensity training(E2, n=6), low-intensity training with insulin injection(EI|, n=6), high-intensity training with insulin injection(EI2, n=6), control without insulin injection and training(C, n=5) and control with insulin injection and no training(CI, n=5). Animals with endurance training were forced to running on motorized treadmill for 8 weeks. The rats with insulin were subcutaneously injected for 8 weeks. Activities of p38 kinase in skeletal muscle were measured by a nonradioactive method.Result: (l)The levels of quiet blood glucose in rats with EI1 decreased significantly to 46% after endurance training for 8 weekscomparing to before endurance training (p<0.01 ), which phenomena were not found in other groups. (2)The levels of blood glucose in rats with E1, EI1. EI2 and CI declined remarkably after a bout of exercise, in which blood glucose of rats with Ell decreased to 83% before exercise(p<0.01). (3)The activities of p38 kinase in skeletal muscle of rats with El, increased significantly after endurance training for 8 weeks comparing to other groups (p<0.05). The p38 activities in skeletal muscle of rats with E1 were significantly higher than that in E2, C and CI (p<0.05).Conclusion: Both low-intensity training and low-intensity training plus insulin injection may significantly increase activities of muscle p38 MAPK in diabetic rats, which suggests that therapeutic prescription on low-intensity training plus insulin injection is very suitable for the diabetes mellitus induced by a deficient supply of endogenous insulin.