Chin C, Gandour-Edwards R, Oltjen S, Choy M
Division of Pediatric Cardiology, University of California, Davis Medical Center, Sacramento 95817.
Pediatr Res. 1992 Oct;32(4):390-3. doi: 10.1203/00006450-199210000-00004.
To determine the fate of the atrioventricular endocardial cushions in cardiac development, we used staining methods for extracellular fibronectin, which is abundant in the endocardial cushions, and actin, which is abundant in the myocytes. White Leghorn chick embryo hearts were harvested at Hamburger and Hamilton stages 26 to 36, and serial sections of the atrioventricular valve region were stained. Before atrioventricular valve formation, fibronectin and actin staining reveal separation between the fibronectin-rich endocardial cushions and the actin-rich myocardial layer. The developing mitral valve leaflets at all of the observed stages contain a fibronectin-rich matrix but no actin-rich myocytes. In contrast, the tricuspid band includes both fibronectin matrix and actin-rich cells. We conclude that the mitral valve leaflets in the chick form predominantly from the endocardial cushion tissue, and the tricuspid band receives contributions from both the endocardial cushions and surrounding myocardium.
为了确定心脏发育过程中房室心内膜垫的命运，我们使用了针对细胞外纤连蛋白和肌动蛋白的染色方法，细胞外纤连蛋白在心内膜垫中含量丰富，肌动蛋白在心肌细胞中含量丰富。在汉伯格和汉密尔顿第26至36阶段采集白来航鸡胚胎心脏，并对房室瓣区域进行连续切片染色。在房室瓣形成之前，纤连蛋白和肌动蛋白染色显示富含纤连蛋白的心内膜垫与富含肌动蛋白的心肌层之间存在分离。在所有观察阶段，发育中的二尖瓣小叶都含有富含纤连蛋白的基质，但没有富含肌动蛋白的心肌细胞。相比之下，三尖瓣带既包括纤连蛋白基质，也包括富含肌动蛋白的细胞。我们得出结论，鸡的二尖瓣小叶主要由心内膜垫组织形成，而三尖瓣带则接受来自心内膜垫和周围心肌的贡献。
