The Role Of Nrf2 In The Intervention Of Different Exercises On Oxidative Stress In The Skeletal Muscle Of Type 2 Diabetic Rats

Objective: Observe the different effects of endurance and resistance exercise on skeletal muscle structure and oxidative stress in diabetic rats,and investigate the role of Nrf2 in oxidative stress of skeletal muscle in diabetic rats with different exercise interventions.Methods: Healthy male SD rats were randomly divided into a pre-control group(pC;n=24)and a pre-model group(pD;n=36).At the 8th week,pD rats were injected intraperitoneally with small doses of streptozotocin(STZ,30m/kg),and 72 hours later,vein blood was taken from the tail to test non-fasting blood glucose to determine whether the diabetes model was successful.Successful Rats in the pD group were randomly divided into diabetes group(D),diabetes+aerobic exercise group(DA),and diabetes+resistance exercise group(DR);rats in pC group were assigned to blank group(C),control+aerobic exercise group(CA)and control+resistance exercise group(CR).Rats in CA and DA groups were given treadmill exercise without weight-bearing exercise.Rats in CR group and DR group were exercised with weight-bearing ladders.They were trained for 8 weeks.Eight weeks later,blood samples were taken to detect blood glucose,insulin.HE staining and transmission electron microscopy were used to observe the changes of skeletal muscle structure in diabetic rats.DHE staining was used to detect skeletal muscle ROS level,biochemical method was used to detect skeletal muscle MDA level,and Western Blot was used to detect Nrf2.HO-1,NQO1 protein expression..Results:(1)FBG was significantly increased in diabetic rats at 8 weeks,and FINS was significantly decreased,and AUC was significantly increased.Both exercise interventions can improve the above indicators.Resistance training improved FBG,FINS,and AUC more significantly.(2)Pathological changes of skeletal muscle structure occurred in 8 weeks of diabetes in rats.The general structure showed rhabdomyolysis,ultrastructure showed mitochondrial damage,endurance exercise and anti-group exercise could improve skeletal muscle structure abnormalities.(3)The levels of ROS and MDA in skeletal muscles of rats with diabetes increased significantly after 8 weeks of diabetes.Endurance exercise significantly reduced the levels of ROS and MDA,and resistance movement reduced the tendency of ROS and MDA,but it was not statistically significant.Endurance exercise intervention significantly reduced the level of MDA after intervention of resistance exercise.(4)The expression of Nrf2 protein in skeletal muscle of diabetic rats increased significantly in 8 weeks compared with the control group.The expression of HO-1 and NQO1 protein had no significant changes compared with the control group.After the endurance exercise intervention,the expression of Nrf2,HO-1,and NQO1 protein was significant.Increased;Nrf2 protein expression increased significantly after resistance exercise intervention,and the expression of HO-1 and NQO1 protein was up-regulated,but it was not statistically significant.Conclusions:(1)Both endurance exercise and resistance exercise can improve the abnormal glucose metabolism in type 2 diabetic rats,and resistance exercise can significantly improve the abnormal glucose metabolism.(2)The pathological changes of skeletal muscle ultrastructure in early type 2 diabetic rats may be caused by mitochondrial damage,which may be caused by oxidative stress;endurance exercise and resistance exercise can relieve skeletal muscle structural abnormalities,but no Significant differences.(3)Obvious oxidative stress appeared in skeletal muscles of rats with early type 2 diabetes;both endurance exercise and resistance exercise can improve oxidative stress.The possible mechanism is to regulate the up-regulation of downstream antioxidant proteins HO-1 and NQO1 by activating Nrf2;The improvement of oxidative stress by endurance exercise is more pronounced than resistance exercise.