中文摘要：

目的：研究离心运动对大鼠比目鱼肌细胞凋亡及Smac蛋白表达的影响。方法：SpragueDawley大鼠随机分为对照组和运动组，运动组又分为运动后即刻、12h、24h、48h、72h。运动组大鼠在跑台上进行-次性离心运动，于运动后不同时间点分批取比目鱼肌待测。结果：与对照组相比，caspase-3活性均在运动后有先升高后降低趋势；caspase-8活性在运动后即刻起明显升高，72h内呈进行性下降；caspase-9在运动后12h、24h和48h明显升高；caspase-12活性只在运动后12h明显升高。大鼠比目鱼肌组织Smac蛋白表达在运动后24h内呈逐渐升高，其mRNA水平在运动后即刻和12h都显著升高。结论：离心运动能诱导比目鱼肌细胞凋亡，且主要是依赖于caspase-8和caspase-9的凋亡途径，依赖于caspase-12凋亡途径较之于其他两条途径有-定的弱势效应。离心运动能引起比目鱼肌线粒体促凋亡蛋白Smac表达上调，Smac在比目鱼肌细胞凋亡过程中发挥了重要作用。

英文摘要：

Objective： The aim of this study is to investigate the effect of eccentric exercise on cell apoptosis and Smac expression in rats＇ soleus muscle. Methods： Adult Sprague Dawley rats were randomly divided into control group and five exercise groups （0 h after exercise, 12 h after exercise, 24 h after exercise, 48 h after exercise and 72 h after exercise）. The exercise groups＇ rats were participated in once treadmill eccentric exercise. They were killed at different time points after exercise and their soleus muscles were extracted. Results： Compared with con- trol group, caspase - 3 activity was increased firstly and then decreased after exercise ; caspase - 8 activity was significantly increased al 0 h after exercise, and then continually decreased within 72 h; caspase -9 activity was significantly increased at 12 h, 24 h and 48 h after exercise; caspase - 12 activity was only significantly increased at 12 h after exercise. The protein expression of Smac in soleus muscle was continually increased within 24 h after exercise, and its mRNA ｜evel was significantly increased at 0 h and 12 h after exercise. Conclusions： Eccentric exercise may induce soleus muscle＇s cell apoptosis in rats, which depended on caspase -8 pathway, caspase -9 pathway, and caspase - 12 apoptotic pathway. The last pathway showed weaker effect than the first two classical apoptotic pathways. The protein expression of Smac in soleus muscle was increased by eccentric exercise. Smac, as a potent pro-apoptotic protein, plays an important role in cell apoptosis in soleus muscle.