【作者】 叶鸣；

【导师】 曾凡星；

【作者基本信息】 北京体育大学 ， 运动人体科学， 2007， 博士

【摘要】 研究目的:本研究模拟高住低训,测试并分析睾酮、ARmRNA、AR蛋白表达、AR与DNA结合能力,骨骼肌总蛋白含量、MHC含量的变化,探讨低氧和运动通过T-AR途径对骨骼肌蛋白质合成的作用及其机理。研究方法:以雄性SD大鼠为研究对象,分成4组:常氧安静组、低氧暴露组、常氧运动组、高住低训组。常氧安静组在常氧环境下安静生活,低氧暴露组每晚在常压低氧(氧浓度13.6%)帐篷中低氧暴露12h,常氧运动组白天在常氧环境中进行耐力运动1h,高住低训组运动和低氧暴露的方式和时间分别同常氧运动组和低氧暴露组。在实验第1、28天分别取材,测试指标。研究结果:(1)28天常氧运动组比常氧安静组血睾酮和骨骼肌睾酮含量略下降,ARmRNA和AR蛋白表达升高,AR与DNA结合能力明显升高,有非常显著性差异(P＜0.01),骨骼肌总蛋白质含量升高,有显著性差异(P＜0.05),MHC含量明显升高,有非常显著性差异(P＜0.01)。(2)28天低氧暴露组比常氧安静组血睾酮和骨骼肌睾酮含量下降,均有显著性差异(P＜0.05),ARmRNA略升高,AR蛋白表达降低,AR活性升高,骨骼肌蛋白质含量略升高,MHC含量稍降低。(3)28天高住低训组比常氧运动组血睾酮、骨骼肌睾酮含量明显降低,ARmRNA下降,AR蛋白表达和AR活性下降,均有显著性差异(P＜0.05),骨骼肌总蛋白含量和MHC含量下降,均有显著性差异(P＜0.05),腓肠肌湿重下降,体重明显下降,有显著性差异(P＜0.05)。(4)1天和28天各组骨骼肌睾酮含量的变化趋势与血睾酮的变化基本一致。结论:(1)本实验选取的耐力运动模型是有利于蛋白质合成的,在此基础上进行低氧暴露模拟高住低训,研究骨骼肌蛋白质合成的调控是可行的。(2)运动后进行低氧暴露比单纯运动可能通过睾酮—AR含量—AR活性各水平抑制蛋白质合成,影响机体恢复。低氧抑制运动后骨骼肌蛋白质合成可能是骨骼肌重量和体重下降的一个主要原因。(3)单纯低氧暴露、运动或运动后进行低氧暴露通过睾酮水平调节AR蛋白水平的改变,最终影响骨骼肌蛋白含量。(4)血睾酮浓度可以反映骨骼肌睾酮含量的变化。更多还原

【Abstract】 Purpose:To study the effect and mechanism of hypoxia and exercise via T-AR pathway on muscle protein synthesis under simulated "Living high-training low(Hi-Lo)" condition,we tested and analyzed the changes of testosterone、ARmRNA expression、AR content、AR and DNA binding ability, muscle total protein、MHC content.Materials and methods:Male Sprague—Dawley rats were randomly divided into four groups as follow:Normoxia sedentary group,Hypoxic exposure group,Normoxia exercise group,living high training low group (HiLo group).the normoxia sedentary group lived in normoxic environment,hypoxic exposure group made hypoxic exposure for 12h in normobaric hypoxic tent(oxygen concentration 13.6%),Normoxia exercise group took 1h endurance exercise in normoxic environment at daytime,Hiho group was exposured in hypoxia at night after trained at daytime,the mode and duration of the both load were identical to hypoxic exposure group and normoxia exercise group.The samples were collected and tested at the ist、28th day.Results:(1) After 28 days,compared with normoxia sedentary group, the normoxia exercise group’ s serum testosterone and muscle testosterone content decreased a little,ARmRNA and AR protein expression increased, AR and DNA binding ability increased(P＜0.01),muscle total protein content enhanced(P＜0.05),MHC content increased significantly (P＜0.01).(2) After 28 days,compared with normoxia sedentary group, the hypoxic exposure group’ s serum testosterone and muscle testosterone content respectively decreased significantly(P＜0.05),ARmRNA improved slightly,AR protein expression decreased,AR activity increased much, muscle total protein content enhanced slightly,MHC content decreased slightly.(3) After 28 days,compared with normoxia exercise group,the HiLo group’ s serum、muscle testosterone content decreased,ARmRNA decreased,both AR protein expression and AR activity decreased significantly(P＜0.05),both muscle total protein content and MHC content decreased significantly(P＜0.05),the wet weight of gastrocnemius decreased,body weight decreased significantly(P＜0.05).(4) The changes of muscle testosterone content in each group were similar to the changes of serum testosterone concentration.Conclusions:(1) The selected mode of endurance exercise was profit for muscle protein synthesis,based on it,it is feasible to study the regulated mechanism of protein synthesis in simulated HiLo condition.(2) Muscle protein synthesis and recovery was decreased much via each leval of testosterone、AR protein content、AR activity in HiLo group than normoxia exercise group.Hypoxia after exercise inhibited muscle protein synthesis and caused the decresing of muscle weight and body weight.(3) Hypoxic exposure、normoxia exercise、HiLo regulated AR protein content by changing serum and muscle testosterone leval,and infulenced muscle protein content finally.(4) Concentration of serum testosterone may reflect the variation of muscle testosterone content.更多还原