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目的探讨呼吸内胚层与咽前间充质细胞发育的关系及对小鼠胚胎心流出道分隔的影响。方法45只胚龄8~13d小鼠胚胎心连续石蜡切片,用抗胰岛因子1(ISL-1)、抗α-平滑肌肌动蛋白(α-SMA)、抗音猬因子(音速波状蛋白,Shh)、抗patched(Ptc1)、抗patched 2(Ptc2)、抗smoothened(Smo)及抗心肌肌球蛋白重链(MHC)抗体进行免疫组织化学及免疫荧光染色。结果胚龄8~9d,ISL-1阳性细胞分布在心包腔背侧壁及前肠两侧间充质,并延伸至原始心管动脉端,心管心肌显较强的Ptc1和Ptc2阳性表达。胚龄10~13d,呼吸内胚层向腹侧延伸,Ptc1和Ptc2呈较强表达,ISL-1阳性咽前间充质细胞围绕呼吸内胚层形成对称的特征性锥体形结构,经动脉囊背侧壁伸入动脉囊腔,形成主肺动脉隔。胚龄12d,主肺动脉隔ISL-1阳性表达基本消失,大部分细胞转变为α-SMA阳性细胞。结论呼吸内胚层的分化发育与咽前ISL-1阳性间充质细胞的发育聚集密切耦联。发育中的呼吸内胚层可能作为组织中心,通过Shh信号通路对ISL-1阳性细胞的聚集提供位置信息。呼吸内胚层的正常腹侧延伸不但可诱导ISL-1阳性细胞的正常迁移和流出道的正常分隔,对流出道的正常形态发生及有效的肺循环建立起重要作用。
Objective To investigate the relationship between respiratory endoderm and the development of pharyngeal mesenchymal cells and its influence on the separation of mouse embryo cardiac outflow tract. Methods Forty-five embryos of embryos aged from embryonic day to day 8 were paraffin-embedded in paraffin sections of hearts. ISL-1, α-SMA, sonic hedgehog ), Anti-patched (Ptc1), anti-patched 2 (Ptc2), anti-smoothened (Smo) and anti-myosin heavy chain (MHC) antibodies by immunohistochemistry and immunofluorescence staining. Results The positive cells of ISL-1 distributed between the dorsal wall of the pericardial cavity and the foregut on the 8th to 9th day after embryo implantation and extended to the original end of the arteriole. The expression of Ptc1 and Ptc2 were stronger in the cardiac muscle. From 10 to 13 days of embryo age, respiratory endoderm extends ventrally, Ptc1 and Ptc2 are strongly expressed. ISL-1-positive pharyngeal mesenchymal cells form symmetrical characteristic pyramidal structures around respiratory endoderm. Wall into the arterial cysts, the formation of the main pulmonary artery. The embryo age 12d, the main pulmonary artery ISL-1 positive expression disappeared, most of the cells into α-SMA positive cells. Conclusion The differentiation and development of respiratory endoderm are closely coupled with the development and accumulation of pharyngeal ISL-1-positive mesenchymal cells. The developing respiratory endoderm may serve as a tissue center that provides location information on the aggregation of ISL-1-positive cells via the Shh signaling pathway. The normal ventral extension of respiratory endoderm can not only induce the normal migration of ISL-1 positive cells and the normal separation of the outflow tract, but also play an important role in the normal morphogenesis of outflow tract and the effective pulmonary circulation.