小鼠胚胎近端流出道隔的融合与心肌化研究  

Process and Mechanism of Fusion and Myocardialization of Cardiac Proximal Outflow Tract in Mouse Embryos

作　　者：赵晓晴[1] 黄国英[1] 陈萍[2] 谢利剑[1] 周国民[3] 

机构地区：[1]复旦大学附属儿科医院心血管中心,上海200032 [2]复旦大学附属妇产科医院超声室,上海200011 [3]复旦大学解剖与组胚教研室,上海200032

出　　处：《中国实验动物学报》2005年第2期65-67,F005-F007,共6页Acta Laboratorium Animalis Scientia Sinica

基　　金：教育部博士点基金(20010246018);上海市曙光计划(2000SG09)。

摘　　要：目的探讨心脏近端流出道隔的融合和心肌化过程及其机制。方法选用胚胎(embryonicday,ED)11.5至出生后1dC57BL6小鼠(简称C57小鼠)。采用免疫组化法测定横纹肌肌动蛋白αSCA,神经嵴细胞的标记物AP2及HNK1,凋亡相关分子activecaspase3的表达;采用TUNEL法原位检测细胞的凋亡程度。结果①近端流出道隔的融合及心肌化的时空模式:近端流出道心内膜垫于ED11.5开始融合,ED13.5基本完成融合;心肌化约从ED12.5开始,至ED15.5基本完成。整个心肌化过程呈现心肌从流出道隔由外向内的内向性生长趋势。②近端流出道隔HNK1的表达:从ED11.5到生后1d近端流出道隔极少或几乎无HNK1表达。③近端流出道隔AP2的表达:ED11.5几乎无表达,ED12.5、ED13.5可见少量表达,从ED14.5以后消失。④近端流出道隔细胞的凋亡:TUNEL和caspase3的检测均表明近端流出道隔的凋亡集中出现在ED12.5和ED13.5,一部分凋亡细胞可能为AP2阳性的神经嵴源性细胞。结论C57小鼠心脏近端流出道隔在胚胎发育早中期开始融合,并逐渐完成心肌化过程,心脏神经嵴细胞可能通过凋亡途径参与了该过程。Objective To study the process and mechanism of fusion and myocardialization of the cardiac proximal outflow tract(OFT)septum. Methods\ The objects were C57/BL6(C57)mice of embryonic day (ED)11 5 to 1day after birth. α SCA, AP 2, HNK 1 and active caspase 3 were detected by immunohistochemistry. Apoptotic cells were identified by TUNEL method. Results\ ①Spatiotemporal pattern of fusion and myocardialization of cardiac proximal OFT septum : The proximal OFT endocardial cushions began to fuse at about ED11 5 and was completed at ED13 5 Myocardialization started at ED12 5 and was completed at ED15 5 During this process the myocardium extended by ingrowth of OFT myocardium into the mesenchymal OFT septum. ②The expression of HNK 1 in proximal OFT septum: There were few of HNK 1 positive cells detected from ED11 5 to 1day after birth. ③The expression of AP 2 in proximal OFT septum:AP 2 expression was not observed at ED11 5, but at ED12 5 and ED13 5 It disappeared from ED14 5 Apoptosis of proximal OFT septum: Apoptosis took place mainly at ED12 5 and ED13 5 Conclusion\ The fusion process of proximal OFT endocardial cushion in C57 mice is completed during early middle stage of embryogenesis, which is followed by myocardialization. The neural crest cells are likely to be involved in this process by their apoptosis.

关 键 词：心脏近端流出道隔 融合 心肌化 神经嵴细胞 细胞凋亡 小鼠 胚胎 流出道畸形 发病机制 

分 类 号：R331.31[医药卫生—人体生理学] R541[医药卫生—基础医学]