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目的探讨早期人胚心静脉窦及传导系的发生发育机制。方法用抗α-平滑肌肌动蛋白(α-SMA)、抗α-横纹肌肌动蛋白(-αSCA)和抗结蛋白(DES)抗体对29例C10~C16期人胚心连续切片行免疫组织化学染色。结果人胚发育C12~C13期,系统静脉汇集形成的静脉窦出现于心包腔尾端原始横膈间充质中,静脉窦壁间充质细胞逐渐分化为-αSCA阳性的静脉窦心肌细胞。C14期,心包腔的扩张使静脉窦进入心包腔内,参与了右心房的形成。DES阳性传导系心肌的分化始于C10期心房室管右侧壁,随发育逐渐向室间沟心肌扩展,发育为房室传导系的希氏束、左右束支及心室腔面的小梁心肌。在心房,DES表达首先出现于C11期心房背侧壁,在C13期,可见静脉窦左背侧壁-αSCA、-αSMA、DES阳性心肌带与左心房底部、房室管背侧壁相延续,这条心肌带可能参与了人胚心静脉窦至房室管传导系的发育。C14~C16期,DES强阳性染色从窦房结经左、右静脉瓣及心房的背、腹侧壁延伸至房室管右侧壁,可能是原始的心房传导通路。结论心包腔尾端原始横膈间充质是人胚静脉窦心肌发生区,原始横膈间充质细胞逐渐分化为心肌细胞,添加到人胚心管静脉端,形成心静脉窦心肌。人胚心传导系心肌的分化始于房室管,随心管发育逐渐向动、静脉端扩展,在C16期,已分化为形态清晰可辨的DES阳性胚胎心传导系。
Objective To investigate the occurrence and development of early human embryo heart sinus and conduction system. Methods 29 cases of C10-C16 human embryo heart sections were obtained by immunohistochemistry with α-SMA, α-stripeactin actin (-αSCA) and anti-descendent (DES) dyeing. Results The human embryos developed from C12 to C13. The venous sinus formed by systemic venous occlusion appeared in the original transperitoneal mesenchyme in the caudal end of the pericardial cavity. The mesenchymal cells in the venous sinus wall gradually differentiated into -SCi positive sinus ventricular myocardium. C14, pericardial dilatation of the venous sinus into the pericardial cavity, involved in the formation of the right atrium. Differentiation of DES positive conduction line began in the right side of C10 atrial ventricular wall, with the development of myocardial dilatation to the ditch, developing atrioventricular conduction His bundle, left and right bundle branch and ventricular cavity surface of the trabecular myocardium . In the atria, the expression of DES first appeared in the dorsal wall of the atrium of C11. In C13, the posterior wall of the left ventricle -αSCA, -αSMA, DES-positive myocardium and the bottom of the left atrium, This myocardial band may be involved in the development of human embryo cardiac venous sinus to atrioventricular conduction system. C14 ~ C16, DES strong positive staining from the sinoatrial node through the left and right venous valves and the atrium of the dorsal and ventral wall extends to the right ventricle wall, may be the original atrial conduction pathway. Conclusions The original transmembrane mesenchyme of the pericardial cavity is the area of sinusoidogenesis in the human embryo. The primitive mesenchymal cells gradually differentiate into cardiomyocytes, which are added to the venous end of the human embryo heart tube to form the sinus venous myocardium. Myocardial differentiation of human embryo heart began in the atrioventricular tube, with the gradual development of cardiac catheterization, venous end expansion, in the C16, has been divided into clear-cut DES positive embryo heart conduction system.