获得性漏斗胸膈肌肌凝蛋白重链MyHC-Ⅱa表达及其意义

Expression of myosin heavy chain MyHC-Ⅱa in diaphragm muscle of the rats with acquired pectus excavatum

目的探讨获得性漏斗胸膈肌肌凝蛋白重链MyHC-Ⅱa表达的变化。方法4周龄SD大鼠72只，随机分为3组，每组24只。肋软骨组和膈肌组分别从胸骨旁切断下位三对肋软骨和造成膈肌物理损伤复制漏斗胸模型，对照组不做任何干预。分别于术后第二、四和八周处死动物，收集膈肌，通过SDS-聚丙烯酰胺凝胶电泳结合Western印迹分析检测膈肌MyHC-Ⅱa的表达。结果测得两组前胸壁凹陷畸形动物各时问点膈肌MyHC-Ⅱa在组间比较差异有显著性，两组MyHC-Ⅱa表达均较对照组减少（P〈0．05），而两实验处理组间比较，仅2周时膈肌组MyHC-Ⅱa表达减少（P〈0．05），4周和8周时MyHC-Ⅱa表达在组间的差异均无统计学意义（P〉0．05）。结论获得性漏斗胸大鼠膈肌肌凝蛋白重链MyHC-Ⅱa表达减少，提示在漏斗胸形成过程中发生了膈肌功能的改变。

Objective To explore the expression of myosin heavy chain MyHC-Ⅱa in diaphragm muscle of the rats with acquired pectus excavatum. Methods Seventy two 4 weeks old Sprague Daw ley （SD） rats were equally and randomly divided into 3 groups including costal cartilage group （group 1 ）, diaphragm group（group 2） and control group （group 3）. In group 1, the lower three double costal cartilages of the rats were cut off from parasternum to induce acquired peetus excavatum. In the group 2, diaphragm muscle of the rats was injured with 95% alcohol. The group 3 was the normal control group. Eight rats of each group were sacrificed every 2 weeks from the second week, and the diaphragm muscle was harvested. The MyHC-Ⅱa expression in diaphragm muscle was detected by West ern blotting. Results The depressed anterior chest wall deformity was gained in group 1 and 2. The MyHC-Ⅱa expression in the diaphragm muscle of these chest wall deformity rats was lower than that of control rats at the 3 endpoints （P〈0.05）. The MyHC-Ⅱa expression of group 2 was lower than that of group 1 only at the 2nd week （P〈0. 05）. Conelusious The expression of MyHC-Ⅱa protein in diaphragm muscle decreased in the rats with acquired pectus excavatum, suggesting diaphragm muscle function changes with the development of funnel chest.