Effects Of A Single Bout Of Eccentric Exercise:MG53 Expression In Skeletal Muscle And Serum CK In Rats

Objective:This study was designed to investigate the effects of a single bout of eccentric exercise on serum CK and muscle MG53 protein expression in rats.Methods:A total of 36 SD rats were randomly divided into three groups,12 rats in each group, sedentary control group(C), eccentric exercise group-rats killed immediately (E0) and 24h after eccentric exercise (E24). Each group was divided into two sub-groups (6 male and 6 female). EO and E24 exercise on a treadmill, with a running speed of 19-21m/min, the slope of -16 °, the movement time of 90min. The speed increased from 10m/min to 19-21m/min in 5min. Blood and muscle samples were obtained after the eccentric exercise immediately and 24h, with serum CK and MG53 protein expression tested in quadriceps femoris and gastrocnemius.Results:(1) After a single bout of exercise, the activity of CK in both male and female rats were increased (E0 vs C), with a significant difference (P<0.01).(2) In quadriceps femoris, the expression of MG53 protein was also increased (E0 vs C), with a significantly difference(P<0.01). Similar results were obtained from gastrocnemius muscle. Both CK activity and MG53 expression returned to the level of control 24 hours after exercise. There is no gender difference in CK activity, but the gender difference in MG53 expression is statistically significant only in the gastrocnemius muscle of EO group.Conclusions:(1) Serum CK can be used as a maker for evaluating the injury of skeletal muscle. (2) The expression of MG53 protein in the quadriceps femoris and gastrocnemius muscle is significantly increased after eccentric exercise, which suggests that MG53 may be related to muscle damage caused by strenuous exercise. MG53 can be considered as a maker for evaluating the injury of skeletal muscle. (3) The increased expression of MG53 protein in skeletal muscle is consistent with the higher activity of CK in serum. Both CK activity and MG53 expression have returned to the levels of control 24 hours after exercise. At the same time, the role of MG53 in the repair of muscle damage is worth further research and discussion.