低氧训练对大鼠骨骼肌HIF-1α基因表达的影响

Effects of hypoxia training on skeletal muscle HIF-1α gene expression in rats

探讨不同低氧训练模式对机体骨骼肌HIF-1αmRNA水平和蛋白水平表达的影响。6周龄SD雄性大鼠120只,经3周适应性训练和力竭实验筛选出90只,随机分成9组:常氧安静对照组、持续低氧安静组、间歇低氧安静组、低住低练耐力组、高住高练耐力组、高住低练耐力组、低住高练耐力组、高住高练后复氧训练组和高住低练后复氧训练组。采用常压低氧仓在13.6%的氧体积分数下(相当于海拔3 500 m的氧体积分数)进行低氧训练,根据血乳酸-速度曲线确定大鼠常氧训练的强度为35 m/min,低氧训练的强度为30 m/min。低氧训练持续时间为6周,每周训练5 d。其中,在第4周末进行运动能力测试,第5周末进行力竭测试,在第6周末的最后一次运动后休息48 h后处死,取材。采用实时荧光定量PCR、免疫组化、Western blot等技术测试大鼠骨骼肌HIF-1αmRNA水平和蛋白水平表达水平的变化,以进一步探讨低氧训练对骨骼肌HIF-1α表达的适应机制。结果显示,与低住低练组相比,高住高练组和高住低练骨骼肌HIF-1αmRNA表达有显著性升高(P<0.05);和常氧安静对照组相比,高住高练骨骼肌HIF-1αmRNA表达升高105%,有非常显著性差异(P<0.01);高住高练后复氧训练1周,大鼠骨骼肌HIF-1αmRNA表达有非常显著性降低(P<0.01),回到常氧安静对照组水平;高住低练后复氧训练1周,大鼠骨骼肌HIF-1αmRNA表达有显著性降低(P<0.05),回到常氧安静对照组水平。可得结论:高住高练、高住低练和持续低氧安静组骨骼肌HIF-1α表达都明显增强,而低住低练和低住高练变化不大,复氧训练后回到常氧安静水平。HIF-1α表达与低氧的程度和时间有明显的依存关系。

The purpose of this study was to probe the effects of different hypoxia training methods on skeletal muscle HIF- 1α mRNA in rats, in order to provide theoretical and applying basis for the application of hypoxia training to sports training. 90 rats are selected from 120 male SD rats （6 weeks old） by three weeks adaptable training and exhaustive test . These rats were randomly divided into 9 groups： normoxia quiet control group（C）, continuing hypoxia group（CH）, intermittent hypoxia group （IH）, normaxia training group（T）, living-high and training-high group（HiHi）, living-high and training-low group（HiLo）, living-low and training-high group（ LoHi）, normoxia training group after HiHi and normoxia training group after HiLo. During the 6 weeks of experimental period, we employed the 13.6% concentration of oxygen （equal to altitude of 3 500 m） in the hypoxic chamber. The rats of hypoxia training were introduced to treadmill. The training speed was 30 m/min in hypoxia and 35 m/min in normoxia. The rats were trained 5 d/week and were sacrificed after 6 weeks. Technology of RQ-PCR, immtmohistochemistry and Western blot are adopted in order to test the mRNA and protein level changes of HIF-1α in rats＇ skeletal muscle to probe further into the mechanisms of the acchmatization in skeletal muscle. It is found that the mRNA level of HIF-1α in rat skeletal muscle increased significantly （P〈0.05） in HiHi and HiLo comparing with LoLo; and the mRNA level of HIF-1α （1.05 times） in rat skeletal muscle increased significantly （ P 〈 0.01 ） in HiHi comparing with C group. Comparing with LoLo group, the mRNA level of HiHi and HiLo increased significantly. The mRNA level of HIF-1α declined significantly in T group after HiHi and HiLo （P 〈 0.05）. The results show that the mRNA level of HIF-1α in rat skeletal muscle increased significantly in HiHi,HiLo and CH. Moreover,the level of HIF-1α is closely related to the extend of hypoxia and the exposure time.