摘要
目的观察缺氧及缺氧复合运动条件下大鼠心肌重塑与肌球蛋白重链(myosin heavy chain,MHC)异构体组成的变化。方法Wisatar大鼠随机分为4组平原对照组、缺氧组、平原运动组和缺氧复合运动组。缺氧复合运动组大鼠持续暴露于模拟海拔5000m高原5周,每天降至4000m高原进行游泳运动1h(6d/周),运动结束后回升至5000m;缺氧组大鼠同时在低压舱内相同海拔高度饲养,但不进行游泳运动;平原运动组和平原对照组在舱外同时饲养,其中平原运动组每天进行游泳运动1h(6d/周)。在末次运动结束后24h处死大鼠,分离左、右心室,称重并计算左、右心室重量指数。用含10%甘油的SDS-PAGE电泳分离左、右心室MHC异构体,观察心室肌MHC异构体组成变化。结果缺氧35d大鼠右心室重量指数增加,缺氧复合运动组大鼠左、右心室重量指数均增加。缺氧组右室MHC异构体组成比例与平原对照组相比无显著变化,平原运动组右室α-MHC异构体比例显著高于平原对照组,缺氧复合运动组右室α-MHC异构体比例显著高于平原对照组和缺氧组,低于平原运动组。左室MHC异构体组成比例变化趋势与右心室相似。结论缺氧复合运动条件下,心肌纤维MHC异构体由β-MHC向α-MHC转换,可能是缺氧条件下适度运动促进机体对高原习服适应的机制之一。
Objective To investigate the effects of chronic hypobaric hypoxia only or combined with exercise on myosin heavy chain （MHC） profile in the ventricles. Methods Wistar rats were randomized into 4 groups： control （C）, hypoxic group （H）, exercise group （E） and hypoxia-exercise group （HE）. Rats of H and HE groups were subjected to simulated 5 000 m hypobaric hypoxia for 5 weeks, except descending to 4 000 m for 1 h/d six times a week and there HE group was forced to swim ceaselessly. C group and E group were kept under normobaric conditions. The swimming program of E group was the same as HE group. In twenty-four hours after the last bout of exercise training, all animals were sacrificed at 4 000 m （ H and HE groups） or at sea level （ C and E groups）, the ventricles were collected and MHC were determined with sodium dodecyl-polyacrylamide gel electrophoresis followed by densitometry analysis. Results The weights of right ventricle （RV） were significantly higher in H and HE as compared with C, and the left ventricle （LV） was significantly heavier in HE than C, indicating RV hypertrophy in chronical hypoxia and hypertrophy of both ventricles in hypoxia-exercise condition. The composition of α-MHC and β-MHC in C were 56.98% and 43.02% in RV, and 70.78% and 29.22% in LV, respectively. The percentage of α-MHC isoform in RV was significantly higher in E （90.93%） and HE （82.95%） than C. The alterations of MHC isoform composition in LV were similar to RV. No significant difference of MHC isoform composition in both ventricles was found between H and C. Conclusion Moderate exercise under hypoxic environment can induce alterations of the expression of MHC isoforms. This could provide a biochemical basis for the exercise promoting acclimation to high altitude.
出处
《第三军医大学学报》
CAS
CSCD
北大核心
2005年第21期2128-2130,共3页
Journal of Third Military Medical University
基金
国家自然科学基金资助面上项目(30200130)~~
关键词
高原
缺氧
心脏
运动
肌球蛋白重链
异构体
high altitude
hypoxia
heart
exercise
myosin heavy chain
isoform
