运动预处理对大鼠心肌CuZn-SOD基因表达的影响

The Effect of Exercise Preconditioning on the CuZn-SOD Gene Expression in Rat Heart

为探讨在高原或仿高原环境下高强度运动的心脏适应机制，通过动物实验模拟高原运动心脏，观察了心肌组织中ＣｕＺｎ－ＳＯＤ ｍＲＮＡ的表达情况。结果表明，在海拔５０００米环境下，大鼠６％负重游泳１０分钟，常压休息１０分钟，重复３次，在运动后３０分钟和２４小时，心肌ＣｕＺｎ－ＳＯＤ ｍＲＮＡ的表达出现两个高峰，分别比对照组升高了４７％和１１２％；而大鼠在单独低压氧环境下不运动，只在缺氧后３０分钟时有ＣｕＺｎ－ＳＯＤ ｍＲＮＡ的表达增高。结果提示：与经典的缺血预处理类似，在高原或仿高原环境下进行高强度训练，很可能是一种由心肌缺血和缺氧等因素所诱发的“运动预处理”现象。

Exercise in the altitude or simulated altitude environment can improve effectively anaerobic endurance ability of athletes. The mechanisms underlying the phenomenon are still controversial. In order to verify the hypothesis that hypoxic intensive training and ischemic preconditioning of the heart could share some biological aspects,Wistar rats underwent a swimming program in a hypobaric chamber at simulated altitude of 5000m consisting of three repeated submaximal swimming (loaded by 6% of weight) for ten-minute and ten-minute rest intervals in the normal environment. Moreover, CuZn-SOD mRNA level was quantitated by Northern blot analysis on RNA prepared from ventricular wall samples. The results showed that the level of CuZn-SOD mRNA in the myocardium appeared two inconsecutive peaks, increasing 47% and 112% after 30min, 24h hypoxic intensive swimming respectively.But in the another group of which rats were inactive in the hypobaric chamber, the level of CuZn-SOD mRNA increased 64% only after 30min intermittent hypoxia. These result suggests that, similarly to ischemic preconditioning in the heart, exercise preconditioning may contribute to the development of heart adaptation in hpoxic intensive training athletes.