Change of Tissue Structure and its Effect on the Cx43 and Cx45 Expression in Koch Triangle Atrioventricular Node Cell of Exercise Rat

The purpose of this study was to investigate the effect of aerobic and high-intensity fatigue training for tissue structure change and the expression of connexin 43(Cx43) and connexin 45(Cx45) of atrioventricula node(AVN) of Koch triangle of rat.Through using step increased load running training way,this paper establishes a aerobic and fatigue training model of rat,then applied respectively HE staining,Masson staining and immunohistochemisty SABC method to observe the change of AVN tissue structure and Cx43 and Cx45 expression of Koch triangle,and used electron microscope to observe the ultramicroscopic structure change of AVN parenchymal cell of Koch triangle.The result shows that the AVN tissue structure of Koch triangle of aerobic training group is normal,the membrane of PC and TC are clear,the chromatin of nucleus are well-distributed,the mitochondria are more abundant than control and fatigue groups,the crista are regularly arranged and the electron-dense granules were abundant.Collagen fiber distributed well,and the expression of Cx43 and Cx45 were distinguished higher than control and fatigue groups.The AVN parenchymal cell of Koch triangle of fatigue training group were scattered,the PC and TC were swollen,the mitochondria of intra-cellular were less and swollen,the crista were irregularly arranged,obscured and disorganized,the heterochromatin of nucleus were massed and margined,the intra-cellular vacuole could be seen,the collagen fiber were abnormally proliferated、twisted and localized dissolution,and the change of Cx43 and Cx45 expression were more distinguished than control and aerobic groups.It concludes that different intensity exercise training affects the change of AVN parenchymal cell and interstitial compostion and the expression of Cx43 and Cx45,and high-intensity fatigue training makes AVN tissue structure micro-injury change and Cx43 and Cx45 expression decline.It suggests that there has close relationship to exercise-induced arrhythmia.