中文摘要：

目的在于探讨低氧及低氧耐力训练条件下肌球蛋白重链（MHC）转换的方式,了解低氧及低氧运动下骨骼肌微细组成的改变。方法：选取SD大鼠30只,随机分为常氧对照组（NC）、低氧对照组（HC）和低氧训练组（HT）。HC组和HT组动物均生活在模拟海拔4000米高度的低氧舱中,HT组进行跑台练习,28天后取浅层胫前肌。RT-PCR方法测定四种MHC亚型mRNA表达,SDS-PAGE方法测定各种MHC亚型蛋白表达。结果：低氧及低氧运动均使MHC-Ⅱa蛋白表达显著下降,MHC-Ⅱx和MHC-Ⅱb蛋白表达显著升高;低氧影响MHC基因表达为MHC-Ⅱa mRNA显著升高,MHC-ⅠmRNA不显著下降;低氧运动使MHC-Ⅱb mR-NA显著升高。结论：低氧及低氧训练使MHC蛋白和基因表达慢型向快型转化。

英文摘要：

The purpose of this study is to explore the way of myosin heavy chain isoform transformation under the condition of hypoxia and hypoxic training. Methods： 30 male Sprague-Dawley rats are divided into three groups randomly, normoxic control group （NC）, hypoxic controls group （HC） and hypoxic training group （HT）. HC and HT group rats are bred under hypoxic condition （simulated 4000 meters altitude）, HT groups rats are performed treadmill running training on a motor-driven treadmill once daily. After 28 days, sTA muscle in all groups are extracted. MHCs mRNA are assayed by RTPCR; MHC protein are determined by SDS-PAGE; Results： Under the condition of both hypoxia and hypoxic training, MHC- Ⅱ a protein is decreased while the MHC - Ⅱx and MHC - Ⅱb protein improved significantly. MHC - Ⅱa mRNA is increased significantly under the hypoxia condition; Under the condition of hypoxic training, MHC- Ⅱb mRNA is increased significantly. Conclusion： Both hypoxia and hypoxic training make slow type MHCs shifted toward fast types in the levels of proteins and mRNA.