Formation of the atrioventricular septal structures in the normal mouse
Formation of the atrioventricular septal structures in the normal mouse
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DOI：
10.1161/01.res.82.6.645
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发表时间：
1998-04-06
影响因子：
20.1
通讯作者：
Anderson, RH
中科院分区：
文献类型：
--
作者：
Webb, S;Brown, NA;Anderson, RH
有时认为房室隔的形成等同于内膜垫的融合，而融合的失败可以解释房室隔的所有缺陷。显然，这是简单的，但不同的房室分隔原基的确切贡献还没有很好地理解，为了澄清这一点，我们研究了正常小鼠胚胎（妊娠10至15天），连续切片，并通过光学显微镜检查。另一组胚胎在显微切割后通过扫描电子显微镜检查。我们的研究结果表明，房室间隔区的发展是非常复杂的，正确的形成需要以下几点：内心脏弯曲的重塑，体静脉窦角围绕肺门的旋转，右房室交界处的扩张，肌性心房和心室间隔的形成，由背侧流出嵴和上级内膜垫桥接，与静脉瓣下缘融合，并从左窦角的头侧肌壁形成冠状窦口。多个原基构成中央间充质团（“中间隔”），包括初级房间隔前缘的间充质、房室内膜垫和前庭棘上的间充质帽。这些部分的融合关闭了第一口，完成了心房和房室分隔。此外，前庭棘有一个中胚层核心，有助于卵圆窝下缘的肌肉化。这与上缘的形成对比，上缘的形成是由于心房壁本身的内折叠而发生的。
It is sometimes thought that formation of the atrioventricular septum is equated with fusion of the endocardial cushions and that failure of fusion can explain all deficiencies of atrioventricular septation. Clearly, this is simplistic, but the exact contribution of different primordia to atrioventricular septation is not well understood, To clarify this, we studied normal mouse embryos (days 10 to 15 of gestation), which were serially sectioned and examined by light microscopy. Another group of embryos was examined by scanning electron microscopy after microdissection. Our results show that development of the atrioventricular septal area is highly complex, Proper formation requires the following: remodeling of the inner heart curvature, rotation of the horns of the systemic venous sinus around the pulmonary portal, expansion of the right atrioventricular junction, formation of the muscular atrial and ventricular septa, bridging by the dextrodorsal outflow ridge and the superior endocardial cushion, fusion with the inferior margins of the venous valves, and formation of the mouth of the coronary sinus from the cranial muscular wall of the left sinus horn. Multiple primordia contribute to a central mesenchymal mass (the "septum intermedium"), including the mesenchyme on the leading edge of the primary atrial septum, the atrioventricular endocardial cushions, and the cap of mesenchyme on the spina vestibuli. Fusion of these components closes the ostium primum, completing atrial and atrioventricular septation. Additionally, the spina vestibuli has a mesodermal core, which contributes to the muscularization of the lower margin of the oval fossa. This contrasts with the formation of the upper rim, which occurs as a result of an infolding of the atrial wall itself.