不同类型心房颤动患者右心房肌缝隙连接蛋白40的分布及表达变化

The Alteration of Connexin 40 Distribution and Expression in Right Atrial Myocardium in Patients with Different Types of Atrial Fibrillation

目的观察非心房颤动者和不同类型心房颤动(房颤)患者右心房肌缝隙连接蛋白40的分布及表达变化,探讨其与右心房大小及房颤发生发展之间的关系。方法共收集23个右心耳心肌标本,非房颤组5个,阵发性房颤6个,持续性房颤5个及永久性房颤7个。采用彩超体表面积标准化法,比较右心房内径大小;免疫荧光共聚焦显微镜观察缝隙连接蛋白40定位分布情况;实时定量聚合酶链反应相对定量检测mRNA表达水平;Westernblot检测蛋白表达水平。结果房颤各组心房内径比非房颤组增大(P<0.05或P<0.01);非房颤组缝隙连接蛋白40主要表达于心肌细胞闰盘位置,而房颤组表达分布紊乱;在mRNA及蛋白表达水平上,阵发性房颤组缝隙连接蛋白40比正常组表达增高;持续性房颤组缝隙连接蛋白40比正常组表达降低;永久性房颤组缝隙连接蛋白40表达进一步降低(P<0.05或P<0.01),缝隙连接蛋白40表达与右心房大小呈明显负相关(R2=0.1938,P<0.05)。结论缝隙连接蛋白40分布紊乱及表达的变化与心房重构密切相关,可能是不同类型房颤发生发展的机制之一。

Aim To observe the change of the distribution and expression levels of connexin 40（Cx40） in right atrial myocardium of people with no-atrial fibrillation（no-AF） and patients with different types of atrial fibrillation（AF）,and to study the associations among distribution and expression changes of Cx40 with AF subtypes,right atrium（RA） size and initiation and development of AF.Methods The total 23 samples of right auricular appendage were collected.Five were designed to no-AF group,six patients with paroxysmal AF（PX）,five patients with persistent AF（PS） and seven patients with permanent AF（PM） served as AF groups.RA size by echocardiographic analysis was indexed to body surface area.Expression and distribution of Cx40 were examined by immunoconfocal microscopy.The mRNA content of Cx40 was measured by relatively real-time quantitative polymerase chain reaction（real-time PCR）.And protein expression level of Cx40 was studied by Western blotting.Results RA size of different AF subgroups was higher than that in no-AF group（P0.05 or P0.01）.Immunoconfocal microscopy showed that Cx40 was mainly localized to the intercalated disc of cardiomyocytes in no-AF group,whereas exhibited heterogenous distribution in AF groups.The mRNA and protein expression levels of Cx40 were increased in PX group compared with no-AF group,however,Cx40 reduced in PS group and even lower in PM group（P0.05 or P0.01）.The protein expression of Cx40 correlated negatively with the size of right atrium（R2=0.1938,P0.05）.ConclusionHeterogenous distribution and the alteration of Cx40 which closely related with heart remodeling may be one of the mechanisms that contributed to the initiation and development of different types of AF.