Li Da-qiang, Feng Yi-bai, Zhang Hui-qin
Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong Science & Technology University, Wuhan 430022, China.
Zhonghua Yi Xue Za Zhi. 2004 Mar 2;84(5):384-6.
To investigate the relationship between the alternations in the expression and distribution of connexin 40 (Cx40) and connexin 43 (Cx43) and atrial fibrillation (AF) in patients with rheumatic heart disease.
Biopsy was conducted to take specimens of right atrial appendage (RAA) from 32 patients with rheumatic heart disease, 21 with AF and 11 with sinus rhythm (SR) during valve replacement. The protein levels of Cx40 and Cx43 were examined by immunoconfocal microscopy and Western blotting. The former was also used to observe the distribution of Cx40 and Cx43 double-labeled with antibodies against Cx40 and Cx43.
Immunoconfocal microscopy showed that the relative expression level of Cx40 protein in the specimens of RAA in the chronic AF group was (0.67 microm(2)/ microm(3) +/- 0.09 microm(2)/ microm(3)), significantly lower than that in the SR group (1.45 microm(2)/ microm(3) +/- 0.16 microm(2)/ microm(3)) (P < 0.01). There was no significant difference in the expression of Cx43 protein between the two groups. Distributed inhomogeneously, Cx40 and Cx43 were mainly located at the side to side interconnections, instead of being confined to the intercalated discs, as observed in the patients with SR. The results of Western blotting were similar to those of immunoconfocal microscopy.
The reduction and redistribution of Cx40 and Cx43 contribute to initiation and persistence of AF in patients with rheumatic heart disease.
探讨风湿性心脏病患者连接蛋白40（Cx40）和连接蛋白43（Cx43）表达及分布变化与心房颤动（AF）的关系。
选取32例风湿性心脏病患者，其中21例合并AF，11例为窦性心律（SR），在瓣膜置换术中取右心耳（RAA）组织活检标本。采用免疫共聚焦显微镜和蛋白质印迹法检测Cx40和Cx43蛋白水平。前者还用于观察抗Cx40和Cx43抗体双标的Cx40和Cx43的分布。
免疫共聚焦显微镜显示，慢性AF组RAA标本中Cx40蛋白相对表达水平为（0.67μm²/μm³±0.09μm²/μm³），显著低于SR组（1.45μm²/μm³±0.16μm²/μm³）（P<0.01）。两组Cx43蛋白表达无显著差异。与SR患者不同，Cx40和Cx43分布不均匀，主要位于细胞间的侧向连接，而非局限于闰盘。蛋白质印迹法结果与免疫共聚焦显微镜结果相似。
Cx40和Cx43的减少及重新分布有助于风湿性心脏病患者AF的发生和持续。
