小鼠胚胎流出道嵴内α-SMA阳性细胞的命运

The fate of α-SMA positive cells in outflow tract ridges of embryonic mouse heart

目的观察小鼠胚胎心脏流出道分隔、重塑过程中流出道嵴内α-SMA阳性细胞的功能与转归。方法用抗α-SCA、抗α-SMA单克隆抗体及TUNEL凋亡染色法对胚龄11-16d小鼠胚胎心脏连续切片进行染色。结果胚龄11-12d,流出道远端分隔过程中,未见细胞凋亡发生。胚龄13-16d,随流出道间充质隔的形成与心肌化,α-SMA阳性细胞聚集形成高度特征性漩涡状结构,并可见细胞凋亡现象。结论不同部位的流出道嵴α-SMA阳性间充质细胞的命运转归不同,其主要功能可能是参与形成升主动脉和肺动脉干相邻壁,并参与流出道间充质隔的心肌化。

Objective To investigate the fate of α-SMA positive cells in endocardial cushions during the septation, remodeling of the outflow tract of mouse embryonic heart. Methods Serial sections of mouse embryos from embryonic day 11 （ED11） to embryonic day 16 （ED16） were stained with monoelonal antibodies against α-SCA and α-SMA, while apoptosis was determined by the TUNEL assays. Results At ED11 - 12, fusion of the distal ridges resulted in the formation of the facing walls of the intrapericardial ascending aorta and pulmonary trunk. Apoptosis was not shown during the septation of the distal part of the outflow tract. At ED13- 16, fusion of the proximal ridges and subsequent myocardialization were accompanied by accumulation of α-SMA positive cells into a characteristic central whorl in which cell apoptosis could be observed. The formation of myocardiac septum resulted in the partition between subaortic and subpulmonary vestibules. Conclus/on In the distal part of the outflow tract, the α-SMA positive cells take part in the formation of the facing walls of the intmpericardial ascending aorta and pulmonary trunk without apoptosis. In the proximal part of the outflow tract, the α-SMA positive cells play an important role for the myocardialization of the mesenchymal septum. A few of apoptotic cells are observed＇in the central of the outflow tract septum.