中文摘要：

目的：观察急性大强度跑台运动及低频电刺激后大鼠骨骼肌及血清CAⅢ表达的变化，探讨CAⅢ与骨骼肌疲劳之间的关系。方法：36只雄性SD大鼠随机分为对照组、运动组和刺激组。运动组参照Bedford方案进行一次大强度跑台运动，造盛大鼠运动性疲劳；刺激组采用低频电刺激的方法诱发大鼠腓肠肌疲劳。Western blot检测大鼠骨骼肌及血清CAⅢ的表达水平。结果：（1）与对照组相比，运动组大鼠比目鱼肌CAⅢ的表达水平明显降低（P〈0.05），但趾长伸肌及血清CAⅢ的表达水平与对照组相比差异无统计学意义（P〉0.05）。（2）随刺激时间的延长，大鼠腓肠肌的肌张力峰-峰（P-P）值逐渐降低，与刺激开始时相比，刺激10min即显著降低（P〈0.05）；而疲劳指数（FI）则随刺激时间的延长逐渐增加，刺激40min时FI高达52.14％左右。（3）与对照组相比，刺激组大鼠腓肠肌CAⅢ的表达水平显著降低（P〈0.05），而比目鱼肌及趾长伸肌CAⅢ的表达水平虽均有下降，但差异无统计学意义（P〉0.05）。结论：急性大强度跑台运动及低频电刺激诱发疲劳后均可引起相应骨骼肌CAⅢ表达下调（前者表现为比目鱼肌，后者为腓肠肌），表明骨骼肌疲劳的发生可能与其CAⅢ表达下调有关。

英文摘要：

Objective To observe the effects of acute intense treadmill running and low-frequency electric stimu-lation on the expression of CAⅢ protein In skeletal muscles and sera of rats, in order to understand the relation of CAⅢ to the muscle fatigue. Methods Thirty-six male Sprague-Dawley rats were randomly divided into control group,training group and stimulation group. The training group undertook single bout of intense treadmill running to estab-lish skeletal muscle fatigue model. On the other hand,the fatigue of gastrocnemius in stimulation group was induced by low-frequency electric stimulation. The levels of CAⅢ protein in muscles and sera were detected by Western blot.Results （1） There were no significant differences in the CAⅢ protein levels in the extensor digitorum longus and sera between two groups（P〉0.05）. The levels of CAⅢ in soleus in training group were decreased significantly as compared with that in control group （P〈0.05）. （2） As the prolonging of stimulation time, the peak-to-peak values of gas trocnemius muscular tension decreased gradually, and significant differences appeared at 10 min of stimulation comparing with the baseline （P〈0.05）. The fatigue index （FI） increased with the prolonging of stimulation time,and reached 52.14% at 40 min. （3） The levels of CAⅢ in gastrocnemius in stimulation group decreased significantly （P 〈0.05）, and decreased slightly in soleus and extensor digitorum longus（P 〉0.05）, as compared with that in control group. Conclusion The decreased expression of CAⅢ in soleus and gastrocnemius could be respectively induced by acute high-intensive treadmill running and low-frequency electric stimulation, and muscle fatigue probably related to the decreased expression of CAⅢ.