成人心传导系统的增龄性超微结构

目的　观察成人心传导系统超微结构的增龄性变化。方法　采用纵切法分别对窦房结、房室结及房室束取材 ;以横切法取房室束 ,透射电镜观察。结果　 (1)从 2 8岁开始、随年龄增长窦房结和房室结的P细胞发生退行性变 ,表现为线粒体肿胀、空泡及髓鞘样变性、细胞体积变小 ,脂褐素大量增大 ,肌节紊乱、肌丝溶解 ,细胞出现脂肪变性、萎缩、凋亡等变化。T细胞见电子密度有明显区别呈明细胞和暗细胞两种 ,暗细胞线粒体大 ,嵴增多 ,显示功能活跃状态 ,明细胞反之 ;(2 )间质纤维、脂肪组织也伴随逐渐增多 ;(3)房室束的增龄性变化主要表现为束细胞线粒体萎缩及纤维组织逐渐增多 ,束带增宽。结论　采用电镜技术 ,发现心传导系统的细胞分子水平的增龄性变化比光镜下细胞水平提前约 10年。

A ultrastructureal study on the age-related changes of cardiac conduction system in adult human

Objective To study the age related changes of cardiac conduction system in adult human. Methods Longitudinal section of the sino atrial,atrio ventricular node and transvers section of the His bundle were observed under the transmission electronic microscope. Results (1)The retrogression of nodal cells with swelling and myelinogenesis of mitochondria and the amount of lipofuscin were be observed in sino atrial node and atrio ventricular node during the aging;The myolysis and disorded sarcomere as well as fatty change were significantly increased in nodal cells of the older in comparaed with younger,respectively,apoptosis could be seen in some nodal cells. (2)Light cells of dysfunction and dark cells of intensive function occur in sino atrial and atrio ventricular node. (3)The proliferation of fibrous and fatty tissue were be found in cardiac conduction system. (4)Retrogression of the nodal cells and the proliferation of fibrous tissue could also be observed in His bundle. Conclusion The age related changes of cardiac conduction system in adult human should be invesgated in early phase be electronic microscope.