后肢去负荷对小鼠运动耐力的影响及其机制  

Effects of Hindlimb Unloading on Exercise Endurance of Mice and Its Mechanism

作　　者：李景龙[1,2] 张鹏[2] 贺健[2] 刘红菊[2] 任维[1] 陈晓萍[2] 

机构地区：[1]陕西师范大学生命科学院,陕西西安710119 [2]中国航天员科研训练中心航天医学基础与应用国家重点实验室,北京100094

出　　处：《航天医学与医学工程》2015年第2期85-88,共4页Space Medicine & Medical Engineering

基　　金：国家重点基础研究发展973计划(2011CB711003);国家自然科学基金(31171144;81272177);航天医学基础与应用国家重点实验室研究基金(SMFA10A01;SMFA13A01)

摘　　要：目的研究不同持续时间后肢去负荷对小鼠运动耐力的影响并探讨其可能的机制。方法小鼠去负荷7、14、28 d,采用跑台记录小鼠运动至耗竭的距离以评价运动耐力,并利用免疫荧光染色、Western blot等方法检测快慢肌纤维蛋白的表达和肌纤维含量。结果在去负荷7、14、28 d肌萎缩形成过程中,小鼠运动耐力分别比对照组下降30.2%、65.5%、71.7%(P<0.001)。运动耐力进行性下降伴随小鼠后肢比目鱼肌肌肉重量的持续丢失,分别下降16.3%(P<0.05)、27.2%(P<0.001)、29.4%(P<0.001)。Western blot结果表明,比目鱼肌中慢肌纤维特异蛋白Troponin I-SS蛋白表达呈进行性下降,而快肌纤维特异蛋白Troponin I-FS的表达上升。免疫组化分析提示,去负荷7、14和28 d后比目鱼肌中慢肌纤维含量分别比对照组下降2.76%、7.75%(P<0.05)、14.97%(P<0.05)。可见伴随后肢去负荷时间的延长,运动耐力持续下降,且伴有显著慢肌萎缩及慢肌纤维含量减少。结论后肢去负荷可引起运动耐力的渐进性下降,且这种规律性变化与慢肌萎缩和慢肌纤维的选择性丢失有关。Objective To explore the effects of hindlimb unloading with different duration on exercise endurance of mice and the possible mechanism. Methods After 7,14 and 28 days of hindlimb unloading,the distance was measured until exhaustion to compare the exercise endurance of mice with the treadmill. With Western blot and immunohistochemistry methods the changes of Troponin I-SS and Troponin I-FS protein expression and the muscle fiber composition were detected. Results Hindlimb unloading for 7,14 and 28 d induced30. 2% and 65. 5% and 71. 7% decreases of exercise endurance compared with control group respectively（ P〈0. 001）. The decreases of exercise endurance were concomitant with 16. 3%（ P〈0. 05） and 27. 2%（ P〈0. 001） and 29. 4%（ P〈0. 001） loss of soleus muscle mass respectively. Western blot analysis showed the decreased expression of Troponin I-SS and increased expression of Troponin I-FS during unloading-induced muscle atrophy. Immunohistochemistry analysis further indicated that the contents of MHC-I fibers lost 2. 76% and7. 75%（ P〈0. 05） and 14. 97%（ P〈0. 05） after 7,14 and 28 d of hindlimb unloading respectively. Therefore,exercise endurance capacity decreased continuously with the hindlimb unloading,which was accompanied by slow-twitch muscle atrophy and the loss of slow fibers. Conclusion The decreased exercise endurance induced by hindimb unloading may be contributed by the slow-twitch muscle atrophy and the selective loss of slow fibers.

关 键 词：去负荷 肌萎缩 运动耗竭 肌钙蛋白 小鼠 

分 类 号：R852.22[医药卫生—航空、航天与航海医学]