《中国康复理论与实践》

《中国康复理论与实践》 ›› 2015, Vol. 21 ›› Issue (05): 519-523.

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痉挛型瘫痪大鼠骨骼肌DNA甲基化水平与肌纤维构型

王玉昌1，庞伟1，冯欢欢1，刘师振2，张慧3   

  • 收稿日期:1900-01-01 修回日期:1900-01-01 出版日期:2015-05-25 发布日期:2015-05-25

DNA Methylation and Muscle Fiber Configuration on Skeletal Muscle in Spastic Paralysis Rats

WANG Yu-chang1, PANG Wei1, FENG Huan-huan1, LIU Shi-zhen2, ZHANG Hui3   

  1. 1. Rehabilitation Medical Research Institute of Jiamusi University, Jiamusi, Heilongjiang 154002, China; 2. Shandong Jining No. 1 People's Hospital, Jining, Shandong 272000, China; 3. Yanzhou Tielu Hospital, Jining, Shandong 272100, China
  • Received:1900-01-01 Revised:1900-01-01 Published:2015-05-25 Online:2015-05-25

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摘要： 目的探讨骨骼肌在痉挛状态下对DNA甲基化水平的影响及与肌纤维构型的相关性。方法健康5 日龄Wistar 新生仔鼠100 只，随机分为模型组和对照组。前者制备痉挛型瘫痪大鼠模型成功后饲养30 d。对两组大鼠腓肠肌进行肌肉活检。分别进行骨骼肌DNA甲基化水平测定、骨骼肌Ⅰ型肌球蛋白重链mRNA半定量RT-PCR检测，透射电镜观察。结果模型组骨骼肌总体DNA甲基化水平(4.95±0.83)×10%，显著低于对照组的(6.59±0.75)×10% (P<0.001)；模型组骨骼肌Ⅰ型肌球蛋白重链mRNA表达量(1.23±0.31)，显著高于对照组的(0.44±0.29) (P<0.001)。电镜观察，模型组骨骼肌Z线排列不规整，两旁骨骼肌线粒体增多，线粒体肿胀，线粒体嵴部分断裂；粗细肌丝数量关系失衡，肌原纤维包膜融合，有的包膜间隙增宽。结论痉挛型瘫痪大鼠骨骼肌DNA低甲基化，Ⅰ型肌球蛋白重链mRNA高表达；电镜检测以Ⅰ型纤维表现为主。没有充足证据表明骨骼肌DNA甲基化水平与肌纤维构型改变相关。

关键词: 痉挛型瘫痪, 甲基化, 超微结构, Ⅰ型肌球蛋白重链

Abstract: Objective To investigate the DNA methylation of skeletal muscle in spastic paralysis rats and correlation with the muscle fiber configuration. Methods 100 5-day old Wistar rats were randomly divided into model group and control group. The former was established the spastic paralysis modle and reared for 30 days. Then, tissues from the gastrocnemius of all the rats were observed with triplicate DNA methylation, myosin heavy chain-I (MHC-I) mRNA with RT-PCR and transmission electron microscopy. Results The DNA methylation was (4.95±0.83)×10% in the model group, significantly less than (6.59±0.75)×10% in the control group (P<0.001); while the MHC-I mRNA was (1.23±0.31), significantly more than (0.44±0.29) in the control group (P<0.001). The Z-line was disordered, and the mitochondria near the Z-line increased, with edema and partially broken in cristae. The balance between the thick and thin filaments was broken, and myofibrils envelope fused. Conclusion Hypomethylation and hyperexpression of MHC-I mRNA have been found in skeletal muscle of spastic paralysis rats, which may result in type I fibers increase. However, there was no sufficient evidence to support the correlation between the DNA methylation and the secondary pathological changes.

Key words: spastic paralysis, methylation, ultrastructure, myosin heavy chain-I