犬冠状静脉窦肌袖细胞及其缝隙连接蛋白43和缝隙连接蛋白45的分布研究

Study about the distribution of connexin 43 and connexin 45 in the myocardial sleeve in coronary sinus in dogs

目的研究冠状静脉窦肌袖细胞形态走行、分布及其缝隙连接蛋白(Cx)的分布特点,进一步探讨冠状静脉窦肌袖在心律失常中的作用。方法选用新疆成年杂种犬9条,以其冠状静脉窦(CS)为研究标本,分别做Cx43、Cx45免疫组化及HE染色。结果CS的长度为(5．20±0．68)cm,在CS 2．5～3 cm内普遍存在肌袖细胞,CS肌袖纤维以内环外纵的基本模式分布,随着CS窦口向远处延伸,肌袖层分布逐渐减少。在同一横断层或不同层面,肌袖细胞的分布存在呈不均一性。免疫组化证实Cx43在CS表达稀少,Cx45在CS肌袖细胞细胞膜表达丰富,而且随着CS的延伸Cx45表达减少。结论犬CS的肌袖细胞分布存在不均一性,Cx45为其主要缝隙连接蛋白,这似乎可以证明CS具备心脏传导系统缝隙连接蛋白的特点,揭示了CS在更大程度上是一条电传导通道。

Objective The purpose of the study is to investigate orientation and distribution of the myocardial sleeve in coronary sinus and the distribution of connexin 43 and connexin 45 in the myocardial sleeve in coronary sinus. Method The samples of coronary sinus（CS） in 9 dogs were examined by microscopy and immunohistoehemistry,respectively. Small tissue samples from the tip of myocardial sleeves were studied by electron microscopy. Results The average length of CS was （5.20±0.68 ） cm. Myocardial sleeve are found in the the CS. Cardial myocytes grouped in bundles of various orientations according to location, extend cephalically as far as 2.5 - 3.0 cm from the right atrium towards left atrium, The thickness of the cardiac muscle layer varies between different levels. Our observation shows that the myocardial layer became thinner and less compact in the distal part. Cx45 is a common feature throughout the myocardial sleeve. But, for Cx43 ,the expression is not abundant in the sleeve of CS orifice, Conclusion The assembly and orientation of CS orifice is heterogeneous, and Cx45 is a main connexin expressed in the myocardial sleeve. It indicates that CS orifice is an electrical conduction way, which could potentially form a substrate for heterogeneity of electrical coupling.