【摘要】 背景:通过运动和/或低氧来增加机体对低氧的应激程度和时间,可提高机体对运动和/或低氧的适应水平,但目前对急性运动和/或低氧对骨骼肌血管内皮生长因子表达的影响所知甚少。目的:观察急性运动和/或低氧对大鼠腓肠肌血管内皮生长因子表达的影响。设计、时间及地点:随机对照动物实验,于2005-09/2006-09在江苏省人民医院临床实验研究室完成。对象:选用健康雄性SD大鼠108只,随机分为6组:即常氧安静组、急性常氧高强度组、急性常氧中强度组、低氧安静组、急性低练高住高强度组和急性低练高住中强度组,每组18只。段氏PT型鼠跑台为杭州产。实验方法:急性常氧运动模型:运动前48h进行适应活动。高强度运动:运动50m/min×1.5min休2min;中强度运动:运动30m/min×30min。低氧模型:采用低氧仪产生低氧气分压的混合气体,低氧3d,22h/d,氧气12.8%,温度22℃,湿度55%。急性低练高住模型:在急性高、中强度运动后实施上述低氧计划。于各组处理后即刻、2,4h分别处死大鼠4只取大鼠腓肠肌。主要观察指标:用Western-blot法测定大鼠腓肠肌血管内皮生长因子表达。结果:低氧和急性常氧运动增强了血管内皮生长因子表达,运动后低氧削弱了运动诱导的血管内皮生长因子表达,长时间中等强度的运动诱导更多的血管内皮生长因子表达。急性运动和/或低氧后即刻、2h血管内皮生长因子表达最多,其恢复速度由快向慢排序为:低氧或低练高住、常氧运动。结论:急性运动和/或低氧诱导的大鼠骨骼肌血管内皮生长因子的表达属早期速发效应,且存在强度阈值,其恢复速度与表达的幅度成反比,低练高住可能能增强骨骼肌对运动的适应。更多还原

【Abstract】 BACKGROUND:Through exercise and/or hypoxia to increase the body’s stress level and timing of hypoxia,so as to improve the body’s adaptation level to exercise and/or hypoxia.However,little was known concerning the effects of acute exercise and/or hypoxia on vascular endothelial cell growth factor (VEGF) expression in skeletal muscles.OBJECTIVE:To study the effects of acute exercise and/or hypoxia on VEGF expression in rats’ gastrocnemius muscles.DESIGN,TIME AND SETTING:The randomized controlled animal experiment was performed at the Clinical Laboratory,People’s Hospital of Jiangsu Province,between September 2005 and September 2006.MATERIALS:Totally 108 health male SD rats were randomly divided into 6 groups,namely,normoxia quiet,normoxia high intensity,normoxia moderate intensity,hypoxia quiet,living high-training low high intensity and living high-training low high intensity moderated intensity groups,with 12 animals in each group.METHODS:In acute normoxia exercise models,rats were performed adaptive activity at 48 hours prior to experiment.The high intensity exercise was comprised of 50 m/min×1.5 min training with 2 minutes rest.The moderate intensity exercise was 30 m/min×30 min.Hypoxia environment was produced by using low oxygen instrument to simulate hypoxia training,with hypoxia for 3 days,22 h/d,12.8% altitude,with 22 ℃ temperature and 55% humidity.In acute training low-living high models,rats were placed in above hypoxia environment after high intensity or moderate intensity exercise.Four rats were sacrificed at hours 0,2 and 4 after training,and the gastrocnemius muscles were obtained.MAIN OUTCOME MEASURES:The expression of VEGF in rats’ gastrocnemius muscles was detected by using western-blot.RESULTS:Hypoxia and acute normoxia exercise enhanced the expression of VEGF,hypoxia after exercise weakened exercise-induced VEGF expression,and the exercise with long time and common intensity induced the higher level VEGF expression.The expression of VEGF was the most at the time points of instantaneousness and 2 hour after exercise,the sorting of the recovery speed of VEGF changes from fast to slow was:hypoxia or training low-living high and normoxic exercise.CONCLUSION:The expressions of VEGF in rats’ skeletal muscles induced by acute exercise and/or hypoxia belong to the effect of immediate-early,with existing intensity-threshold,which recovery speed is inversely proportional to the expression amplitude;"training low-living high" may be able to enhance the adaptation of skeletal muscles to sports.更多还原