低氧运动后不同恢复环境下大鼠腓肠肌热休克蛋白70基因表达的时程变化

Time Course of Rat Gastrocnemius Heat Shock Protein 70 Gene Expression under Differential Recovery Environment Following Hypoxic Treadmill Exercise

目的:实验旨在观察低氧(氧含量12.7%,相对高度4 000 m)跑台运动后低氧、常氧恢复下大鼠腓肠肌热休克蛋白70(HSP70)基因表达的时程变化。方法:雄性8周龄SD大鼠48只,随机分为低氧运动后即刻组(HE),低氧运动后低氧恢复1 d组(H1)、2 d组(H2)、7d组(H7),低氧运动后常氧恢复1 d组(N1)、2 d组(N2)、7 d组(N7),以及常氧对照组(C),每组6只。运动组进行低氧环境下的跑台运动,运动后将运动组大鼠分别处于低氧和常氧恢复环境,对低氧运动后即刻、低氧运动后低氧恢复及常氧氧恢复1 d、2 d、7 d的大鼠右侧腓肠肌取材进行分析,用实时荧光定量RT-PCR法检测HSP70基因表达水平。结果:运动后即刻大鼠腓肠肌中HSP70基因表达显著高于对照组(P<0.05)。低氧恢复过程中,第1 d、第2 d基因表达上升,且显著高于即刻组(P<0.05),第7 d基因表达显著下降(P<0.05);常氧恢复过程中,第1 d基因表达显著下降(P<0.05)。第2 d、第7 d基因表达缓慢上升。结论:低氧运动后即刻诱导HSP70基因表达水平升高;低氧恢复过程中HSP70基因高水平表达维持的时间要比常氧恢复组要长。低氧恢复1 d,2 d组基因表达水平显著高于相应的常氧恢复组,为低氧恢复中维持高浓度蛋白水平奠定物质基础。

Purpose： This study was to observe the time course of rat gastrocnemius heat shock protein 70（HSP70） gene expression under differential recovery environment following hypoxic（Oxygen Concentration： 12.7%,Relative altitude 4000m） treadmill exercise.Methods： 48 Male 8 weeks old SD rats were randomly divided into 8 groups（n=6）： immediately after exercise（HE）,1d（H1）,2d（H2） and 7d（H7） recovery from normobaric hypoxia environment,and 1d（N1）,2d（N2）,7d（N7） recovery from normoxia,and normoxia control group（C）.Gastrocnemius HSP70 gene expression was detected by real-time fluorescent quantitative RT-PCR.Results： Exercise and hypoxia induced a substantial increase of HSP70 gene expression immediately after exercise（P〈0.05）,and under normobaric hypoxia recovery conditions,at 1 d and 2 d HSP70 gene expression were gradually increased,at 7d gene expression was significantly decreased（P〈0.05） compared with H2;under normoxia recovery conditions,at 1d HSP70 gene expression was remarkably decreased（P〈0.05） comparing with HE,at 2d and 7d,HSP70 gene expression were steadily elevated.Conclusions： These data reveal that hypoxic treadmill exercise could induce HSP70 gene expression increment.The high concentration of HSP70 mRNA under hypoxic condition is longer than that of normoxic condition.The level of 1d and 2d HSP70 gene expression under hypoxia are significantly higher than that of normoxia,respectively.It plays an important role in sustaining the high HSP70 protein concentration under hypoxia condition.