缝隙连接蛋白在心房纤颤患者心房肌的表达及其信号转导途径

Expression of connexin in atrium of atrial fibrillation and its signal transduction pathway

目的 探讨缝隙连接蛋白在心房纤颤 (房颤 )心房肌的表达及其信号转导机制。方法 6 3例接受开胸手术患者 (包括慢性房颤、阵发性房颤、窦性心律患者 ) ,手术时取心房组织 ,应用逆转录 聚合酶链反应技术检测心房肌钙调磷酸酶调节亚单位 (CalcineurinB)、丝裂原激活的蛋白激酶磷酸酶 1(MKP 1)mRNA表达量 ,采用Western印迹方法 ,检测细胞外调节激酶 1(ERK1)、磷酸化细胞外调节激酶 1(P ERK1)、缝隙连接蛋白 4 0 (Cx4 0 )、缝隙连接蛋白 4 3(Cx4 3)蛋白表达量的改变。结果 慢性房颤、阵发性房颤患者左心房与右心耳组织Cx4 0蛋白表达量 (左心房 :2 2± 0 8,2 2± 0 6 ;右心耳 :2 1± 0 5 ,2 0± 0 8) ,与窦性心律组相比 ,差异有显著意义 (P <0 0 5 )。慢性房颤、阵发性房颤患者Cx4 3蛋白仅在左房组织表达高于窦性心律瓣膜病组 (3 1± 0 6 ,2 8± 0 7vs 1 0± 0 2 ,P均<0 0 5 )。CalcineurinBmRNA、MKP 1mRNA、P ERK1蛋白在慢性房颤、阵发性房颤患者各组的表达水平均明显高于窦性心律组 (P <0 0 5 )。免疫组化显示慢性房颤、阵发性房颤患者Cx4 0、Cx4 3均分布紊乱 ,聚集于细胞的侧边、胞浆或核周。结论 房颤患者心房肌Cx4 0、Cx4 3蛋白基因表达增高且分布异常 ,可能与ERK1及一些磷酸酶的异?

Objective To explore the expression of connexin (Cx) and its signal transduction pathway in the atrium of patients with atrial fibrillation (AF). Methods Atrial tissue samples of 63 patients undergoing cardiac surgery, including patients with chronic AF or paroxysmal AF (PAF), and those with sinus rhythm, were collected during operation. The mRNA expressions of calcineurin B and mitogen-activated protein kinase-1 (MKP-1) were detected by semi-quantitative RT-PCR. The protein expressions of extracellular-signal regulated kinase 1 (ERK1),phospho-ERK1 (P-ERK1), Cx40 and Cx43 were analyzed by Western blotting. HE staining and immunohistochemistry were used to examine the distribution of Cx40 and Cx 43.Results Increased amounts of Cx40 protein (left atrium: 2.2±0.8, 2.2±0.6; right appendages: 2.1±0.5, 2.0±0.8) were found in the left atrium and right appendages of patients with Chronic persistent AF(CAF) or paroxysmal AF(PAF) (P<0.05). The expression of Cx43 was only increased in the left atrium of patients with CAF and PAF (3.1±0.6, 2.8±0.7 vs 1.0±0.2, both P<0.05). The amounts of Calcineurin B mRNA, MKP-1 mRNA and P-ERK1 of patients with CAF or PAF were significantly increased compared with patients in sinus rhythm (P<0.05). Immunohistochemistry revealed that Cx40 and Cx43 of CAF patients and PAF patients acculmated in the intracellular site, and at the lateral member of atrial cells, both connexins redistributed. Conclusion The increased expression and disorderly distribution of Cx 40 and Cx 43 protein in the atrium of AF patients may be related with the abnormal activation and disequilibria of regulation of ERK1, MKP-1 and calcineurin.