低压低氧环境对大鼠心肌肌球蛋白重链表达的影响

【目的】 研究模拟高原低压低氧环境对小鼠心肌肌球蛋白重链α、β亚型表达的影响。【方法】取清洁级SD大鼠20只，随机分成2组：常氧组和模拟高原6000m低压低氧组。记录各组大鼠心脏指数。制作各组心肌组织切片，常规HE染色观察心肌细胞形态改变。免疫荧光法检测各组心肌肌球蛋白重链α-MHC和β-MHC两种亚型蛋白的表达变化。【结果】常氧组和低压低氧组大鼠心脏指数差异不具有统计学意义（P〉0．05）。HE染色可见低压低氧组大鼠心肌细胞水肿，心肌间质内小血管及毛细血管明显扩张充血。低压低氧组大鼠心肌中MHC蛋白质表达水平异常改变，即α-MHC蛋白表达量增高而α-MHC蛋白表达量下降。【结论】模拟高原6000m高原低压低氧可致大鼠心肌细胞形态异常改变同时可刺激心肌MMC亚型表达出现“由快到慢”的趋势，提示MHC表达异常参与了心脏重塑，可能是高原低压低氧致心力衰竭发生、发展的基础。

Effects of simulated high-altitude hypobaric hypoxia on the expression of myosin heavy chain in rat myocardium

Objective] To study the effects of simttlated high-altitude and hypobaric hypoxia on the expressions of myosin heavy chain （MHC） isoforms in rat myocardium. Methods] Twenty SD rats were divided randomly into two groups （ n = 10） . The hypoxia disposal was that the rats were put in a hypobaric chamber at a simulated altitude of 6 000 meters for 24 hours. Rat hearts from the hypobaric hypoxia group and the control group were collected. The heart weight to body weight ratio （ H/B ratio） were recorded. Morphologic changes of heart were observed by HE staining.The expressions of α-MHC and β-MHC protein were studied by immunofluorescence fechnigne on paraffin-embedded sections. Results] Under simulated high-altitude hypobaric and hypoxia, there was is no aheration inH/B ratio （ P 〉 0.05） . In hydropic degeneration and capillary dilation and hyperemia were observed by HE staining. MHC-α protein expression was downregtdated and β-MHC protein expression was upregulated as contrasted with nomal rat myocardium. Conclusions] simulated high-altitude hypobaric and hypoxia mdy injury the myocardium and stimulate the expression of MHC isoforms from fast type to slow type in rat myecardium, which is related with heart remodeling and may be the molecular basis of heart failure caused by high-altitude and hypobaric hypoxia.