运动对低氧状态下大鼠骨骼肌中低氧诱导因子表达的影响

Effects of hypoxia-combined-exercise on the expression of hypoxia inducible factor in skeletal muscle of rats

目的:观察低氧及低氧复合运动对大鼠腓肠肌中的低氧诱导因子-1α表达的影响,探讨运动在骨骼肌低氧适应中的意义。方法:实验于2003-12在广州体育学院完成,实验动物选择雄性SD2月龄大鼠80只,按照抽签法随机分为4组,常氧安静组、常氧运动组、低氧安静组、低氧运动组,每组20只。建立大鼠低氧及低氧复合运动模型,低氧安静组、低氧运动组每天置减压帐篷内23h,并在减压帐篷内进行跑台训练1h,跑台速度设定为25m/min。常氧运动组大鼠训练同前两组。低氧安静组不运动,其余条件与低氧运动组一致。所有实验动物分批(每次4只)于实验开始后第3,7,10,14天用30g/L戊巴比妥钠麻醉,迅速完整切除左侧腓肠肌,称重后取1g肌肉组织制作成肌肉悬浆以备用。运用表面加强激光解析电离化芯片技术检测法测定大鼠腓肠肌中的低氧诱导因子含量的变化。结果:在实验过程中,有3只动物因不能完成实验而被淘汰,77只大鼠数据有效,进入最后统计的数据每组为4只。①低氧诱导因子-1α蛋白的分子量M r为120167,表明其存在源后修饰。常氧安静组及低氧安静组实验后第3天未检测到低氧诱导因子-1α的表达。常氧运动组表达量低于低氧运动组,差异有显著性[(6.27±1.58),(14.69±1.34),P<0.001]。②常氧安静组实验后第7天仍未检测到低氧诱导因子-1α蛋白表达,常氧运动组表达量有一定程度降低,低氧安静组可以检测到表达,低氧运动组表达量增加,低氧运动组与常氧运动组及低氧安静组有明显差异[(20.13±0.85),(4.81±0.69),(2.27±0.61),P<0.001]。③常氧安静组实验后第10天仍未检测到低氧诱导因子-1α蛋白表达,常氧运动组表达量有一定程度降低,低氧安静组可以检测到表达,低氧运动组表达量增加,低氧运动组与正常氧运动组及低氧安静组有明显差异[(26.23±0.84),(3.76±0.63),(3.65±0.73),P<0.001]。④正常氧安静组实验后第14天仍未检测到低氧诱导因子-1α蛋白表达,正常氧运动组表达量有一定程度降低,低氧安静组可以检测到表达,低氧运动组表达量增加,低氧运动组与常氧运动组及低氧安静组有明显差异[(29.54±0.61),(1.29±0.35),(13.47±0.62),P<0.001]。⑤低氧诱导因子的含量与低氧程度、时间以及运动均有交互作用,在本实验设计的低氧条件下,低氧时间越长,同时给予适当的运动训练的大鼠骨骼肌中含量最高。结论:低氧条件下适当运动可以通过增加低氧诱导因子的表达诱导相关基因的表达,提高骨骼肌的低氧适应能力,起到保护骨骼肌的作用。

AIM： To study the effects of hypoxia and hypoxia combined exercise on the expression of hypoxia inducible factor-1 （HIF-1）in gastrocnemius of rats, and explore the significance of exercise in hypoxia adaptation of skeletal muscles. METHODS： The experiment was conducted in Guangzhou College of Physical Education during December 2003. Eighty male SD rats aged 2 months were divided randomly into four groups according to drawing： noexercise control group, exercise-control group, hypoxia group and hypoxiacombined-exercise group with 20 rats in each group. Hypoxia and hypoxiacombined-exercise models were made. The rats in the hypoxia group and hypoxia-combined-exercise group were put into canvas with decompression for 23 hours every day, and treadmill training was performed for 1 hour within decompression canvas, and the speed of treadmill was set at 25 m per minute. The exercise performed in the exercise-control group was the same to the former two groups. The rats in the hypoxia group were treated with the same training with those in the hypoxia-combined＇exercise group except no exercise. All the experimental animals were anesthetized with 30 g/L sodium pentobarbital at the 3^th, 7^th, 10^th and 14^th days after the beginning of experiment in batch （4 rats every time）. Gastrocnemius at the left side was cut rapidly and completely. After weighing, 1 g muscle tissue was gained to make muscle slurry for preparing. Changes of contents of HIF in gastrocnemius of rats were detected with Surface-enhanced Laser Desorption/lonization （SELDI）. RESULTS： During the experiment, three rats were excluded because they could not finish the trial. Data of 77 rats were effective, and 4 rats in every group were involved in the result analysis. ① Molecular weight Mr of HIF-1 ct protein was 120 167, which indicated that it had post source modification. The expression of HIF-1 α was not found at the 3^th after experiment in the no-exercise control group and hypoxia group. Expression in the exercisecontrol group was lower than that in the hypoxia-combined-exercise group, and its difference was significant [（6.27±1.58）, （14.69±1.34）,P 〈0.001 ]. ② The expression of HIF-1 α was not found at the 7^th after experiment in the no-exercise control group. The expression in the exercise-control group decreased partly. The expression in the hypoxia group could be found. The expression in the hypoxia-combined-exercise group increased. There were significant differences in the hypoxia-combined-exercise group, exercisecontrol group and hypoxia group [（20.13±0.85）, （4.81±0.69）, （2.27±0.61） P 〈 0.001]. ③ The expression of HIF-1 α was still not found at the 10^th after experiment in the no-exercise control group. The expression in the exercise-control group reduced partly. The expression in the hypoxia group could be found. The expression in the hypoxia-combined-exercise group increased. There were significant differences in the hypoxia-combined-exercise group, exercise-control group and hypoxia group [（26.23±0.84）, （3.76±0.63）,（3.65±0.73）,P 〈0.001]. ④ The expression of HIF-1 α was still not found at the 14^th after experiment in the no-exercise control group. The expression in the exercise-control group fell down partly. The expression in the hypoxia group could be found. The expression in the hypoxiacombined-exercise group was fortified. There were significant differences in the hypoxia-combined-exercise group, exercise-control group and hypoxia group [（29.54±0.61 ）, （1.29±0.35）, （13.47±0.62）,P 〈 0.001]. ② The content of HIF had interaction with hypoxia degree, time and exercise. Under the hypoxia condition designed by this trial, the longer the hypoxia time, the higher the content in the skeletal muscles of rats that was given suitable exercise at the same time was. CONCLUSION： The hypoxia-combined-exercise can induce the expression of related gene by increasing the expression of HIF, enhance the hypoxia adaptive capacity of skeletal muscles that plays the effect of protecting skeletal muscle.