不同运动量游泳运动对大鼠左心室心肌闰盘结构和间隙连接蛋白43的影响

Effects of different loading swimming exercises on structure of myocardial intercalated disk of ventriculus sinister and connexin 43 in rats

目的:探讨不同运动量游泳运动对大鼠左心室心肌闰盘结构和间隙连接蛋白43(Cx43)的影响,以期为运动对心肌的生理和病理变化研究提供参考资料。方法:SD大鼠分为不同运动量运动组和力竭运动组,前者进行12周的低、中和高运动量游泳运动,后者进行1次力竭游泳运动。运动后取左心室心肌组织进行常规透射电镜样品制备和Cx43免疫组化染色,电镜观察左心室心肌闰盘结构变化,光镜和图像分析方法对Cx43的分布和含量改变进行研究。结果:安静对照组大鼠左心室心肌细胞闰盘结构清晰,由粘着连接、桥粒和间隙连接组成,呈阶梯状排列,Cx43主要分布在闰盘处。低和中运动量大鼠闰盘结构、Cx43分布和含量与安静对照组差异不大。高运动量大鼠闰盘连接间隙明显增宽,Cx43在心肌细胞侧对侧连接增加,含量明显降低。力竭运动大鼠闰盘结构紊乱,局部断裂或折迭;力竭后即刻Cx43含量与安静对照组差异不明显,随着力竭运动后时间的延长,Cx43含量显著降低。结论:高运动量和力竭运动可以导致左心室心肌闰盘结构破坏,Cx43降解和分布模式改变。

Objective： To explore the effects of different loading swimming exercise on structures of myocardial intercalated disk of ventriculus sinister and connexin 43（Cx43） in rats, so as to provide some information for the changes of physiology and pathology by the exercise-induced injury and recuperation of cardiac muscles. Method： SD rats were randomly divided into two groups： different loading exercise group and exhaustive exercise group. In the different loading exercise group, 12-week low, moderate and high loading swimming models were carried out in rats. In the exhaustive exercise group, a single exhaustive swimming was carried out in rats. After exercise, rat＇s ventriculus sinister were cut off, and treated with routine procedures of transmission electron microscopy before observing the structures of intercalated disks. Immunohistochemical technique and image-analysis method were used to study the changes in distribution and content of Cx43 in myocardial tissues. Result： In control group rats ventriculus sinister showed clear structure of myocardial intercalated disks, which were composed of adhering junction, desmosome and gap junction and arranged as a flight of stairs. Cx43 was mainly distributed in intercalated disk. In low and moderate loading swimming groups the structure of intercalated disk and the distribution and content of Cx43 were similar to that of control group. In high loading swimming group the gaps of intercalated disks became wider, the contents of Cx43 decreased, and distribution of Cx43 at side-to-side junction of myocardial cells increased. In exhaustive exercise group the myocardial intercalated disks were disorganized and some regions of intercalated disks were destroyed or folded; the content of Cx43 was similar to control group at the end of exhaustive exercise, but significantly decreased with time prolongation after exhaustive exercise. Conclusion： High loading swimming and exhaustive exercise could destroy the structures of myocardial intercalated disks of ventriculus sinister, and result in degradation and change in distribution pattern of Cx43.