心房颤动患者心房肌细胞超微结构及凋亡水平的改变

探讨心房颤动(简称房颤)与心房肌组织细胞学重构的关系。38例风湿性心脏病二尖瓣狭窄换瓣术者,其中窦性心律者13例(A组)、阵发性及房颤持续时间小于6个月者8例(B组)、房颤持续时间大于6个月者17例(C组)。外科手术时取三组患者右心耳少许,利用透射电镜观察心房肌细胞超微结构改变,以及利用TUNEL法标记心房肌细胞凋亡并计算凋亡指数。结果:B、C组心房肌细胞超微结构有明显变化,如心肌纤维稀疏、排列紊乱,细胞收缩成分减少、线粒体肿胀、肌浆网扩张,纤维组织增生、细胞水肿、坏死表现;C组变化更明显。B、C组细胞凋亡指数与A组比较,显著增高(分别为44.53%±11.08%,67.96%±16.09%vs19.68%±15.36%,P均<0.05);房颤持续时间越长其凋亡指数越高。结论:心房肌的组织细胞学重构可能在房颤的发生或维持中起重要作用。

Changes of Ultrastructure and Levels of Myocardial Cell Apoptosis in Patients With Atrial Fibrillation

To explore the relationships between the atrial fibrillation (AF) and the cellular remodeling, 38 patients with mitrial stenosis undergoing open heart surgery were studied. They were divided into three groups: 13 cases with sinus rthymia(A group), 8 cases with paroxysmal AF or AF maintained less than 6 months(B group) and 17 cases with AF maintained more than 6 months(C group). The atrial tissue was obtained from the right appendage and were stained by EdUTP-in situ end-labeling and observed by electric microscopy. Results: Marked changes in atrial myocytes cellular substructures were revealed in group B and group C, such as loss of myofibrils, changes in mitochondrial shape and size, fragmentation of sarcoplasmic reticulum and cell necrosis. The changes in group C were the most obvious. Apoptotic indexes of group B and C with were significantly higher than that of group A (44.53%±11.08%,67.96%±16.09% vs 19.68%±15.36%,P<0.05)). The more the longer of AF sustained, the obvious of apoptotic index was. Conclusion:Cellular remodeling may be important in the initiation and the maintenance of AF.