急性离心运动后骨骼肌超微结构、钙依赖性蛋白酶和泛素的动态变化

Dynamic Changes in Ultrastructure,Calpains and Ubiquitin in Skeletal Muscle after Acute Eccentric Exercise

目的:探讨1次离心运动后大鼠骨骼肌超微结构、Calpains和Ubiquitin的动态变化。方法:30只雄性SD大鼠随机分为对照组和1次离心运动后即刻组、24 h组和7天组。各运动组大鼠进行1次下坡跑运动,速度16 m/min,坡度?16°,运动100 min后休息10 min,再运动100 min,总时间200 min。分别在急性运动后即刻、24 h和第7天取材,测定血清LDH、CK活性和股四头肌超微结构及Calpain-1、Calpain-2和Ubiquitin含量。结果:①1次离心运动后即刻组大鼠股四头肌肌丝排列混杂、卷曲;运动后24 h出现轻度溶解、断裂,Z线不规则,局部Z线消失;运动后7天超微结构与对照组相比无显著变化。血清CK和LDH活性变化与股四头肌超微结构变化一致。②与对照组相比,运动后即刻组大鼠股四头肌Calpain-1、Calpain-2和Ubiquitin含量均有所降低,但均无显著性差异;运动后24 h组股四头肌Calpain-1、Calpain-2和Ubiquitin含量均显著高于对照组和运动后即刻组;运动后7天组与运动后24 h组相比均显著下降,而与对照组相比均无显著性差异。结论:①1次离心运动所致的骨骼肌损伤有一定的延迟性,骨骼肌损伤在运动后即刻从整体看并不严重,但在运动后24 h出现明显损伤,运动后7天基本恢复。②急性离心运动后骨骼肌Calpain和Ubiquitin含量变化与骨骼肌损伤的动态变化基本一致。

Objective To investigate the dynamic changes in ultrastructure,calpains and ubiquitin in skeletal muscle after single bout of eccentric exercise.Methods Thirty male SD rats were randomly divided into control group,immediate post-exercise group,24-hour post-exercise group and 7-day post-exercise group.Rats in exercise groups performed single bout of downhill running（16 m/min,？16 degree）for 200 minutes.Quadriceps were drawn immediately 24 hours and 7 days after the eccentric exercise,respectively,and the changes in ultrastructure,serum LDH and CK activity,and calpain-1,calpain-2,and ubiquitin concentration quadriceps were observed.Results ① In quadriceps,mixed arrangement and curled filaments appeared immediately after eccentric exercise;mild dissolution,fracture,Z-line irregular,and partial disappearance of Z lines occurred 24 hours after eccentric exercise;there were no significant changes in control group 7 days after eccentric exercise;the activities of serum CK and LDH changed consistently with the alteration of ultrastructures.② As compared with the control group,the concentrations of calpain-1,calpain-2 and ubiquitin in quadriceps decreased immediately after exercise without significant statistical difference.The concentrations of calpain-1,calpain-2 and ubiquitin in quadriceps 24 hours post-exercise were significantly higher than that in control group and immediate post-exercise group.As compared with immediate post-exercise and 24-hour post-exercise,the contents of calpain-1,calpain-2 and ubiquitin in quadriceps significantly decreased 7 days post-exercise,whereas no significant statistical difference was found as compared with the control group.Conclusion ① The skeletal muscle damage induced by eccentric exercise appeared most seriously 24 hours after exercise and restored basically 7 days after exercise;② The changes in calpain and ubiquitin contents in skeletal muscle were basically the same as the dynamic changes in ultrastructure of skeletal muscle.