一次和重复大强度离心运动前后大鼠骨骼肌超微结构变化

目的:探讨一次和重复离心运动后大鼠骨骼肌超微结构的改变。方法:72只Wistar大鼠分为正常对照组、一次离心运动组和重复离心运动组。一次大强度运动组采用速度18 m/min、坡度-16°的下坡跑运动,大鼠先运动30 min休息5 min,再运动30 min。重复运动在一次运动结束一周后进行(运动2次),观察一次和重复运动后即刻、24 h、48 h、72 h和168 h大鼠股四头肌超微结构变化。结果:一次运动后48 h肌节损伤情况最严重,肌节紊乱甚至消失,Z线断裂,肌丝溶解,72 h出现部分恢复。重复运动后24 h,线粒体严重破坏,48 h线粒体结构逐渐恢复,72 h肌纤维已经重建,但线粒体数量、结构和功能尚未完全恢复。结论:重复运动较一次大强度离心运动促进肌纤维再生及骨骼肌重建,特别是运动后48~168 h线粒体结构与数量恢复速度加快,可能促进了受损组织有氧代谢能力提高,有利于受损组织再生。

The Ultrastructural Changes in Skeletal Muscle of Rat after Acute and Repeated Eccentric Exercise

Objective To study the ultrastructural changes in skeletal muscle of rat after acute and repeated eccentric exercise.Methods 72 rats were randomly assigned to normal control group,acute eccentric exercise group and repeated eccentric exercise group.Rats in acute eccentric exercise group ran on a downhill treadmill(-16° slope) twice at a speed of 18m/min for 30 minutes with an interval of 5 minutes.Rats in repeated eccentric exercise group underwent the protocol as rats in acute eccentric exercise group twice with an interval of 1 week.The ultrastructural changes in skeletal muscle were observed 24 hours,48 hours,72 hours and 168 hours after the acute or repeated exercises.Results Disordered or disappeared sarcomere,fractured Z-line,and decomposed myofilament occurred 48 hours after acute exercise,and partially restored within 72 hours.Mitochondria was severely damaged 24 hours after repeated exercise,and restored within 72 hours,whereas mitochondrial number,structure and function did not completely recovered.Conclusions Compared to the acute eccentric exercise,repeated eccentric exercise causes less ultrastructural changes in skeletal muscle.