Sonic Hedgehog信号通路分子及胰岛素增强子结合蛋白在小鼠胚胎心流出道发育的早期表达

Expression of Sonic Hedgehog signaling members and ISL-1 in morphogenesis of the outflow tract in mouse embryonic heart

目的探讨胰岛素增强子结合蛋白(ISL-1)及音速波状蛋白(Sonic Hedgehog,Shh)信号通路分子在小鼠胚胎心流出道的早期表达特点与其发育的关系。方法取胚龄8-13 d小鼠胚胎心脏40例制作连续石蜡切片,应用抗音速波状蛋白(Shh)、抗Smoothened(Smo)、抗Patched(Ptc1)、抗Patched 2(Ptc2)、抗ISL-1、抗心肌肌球蛋白重链(MHC)、抗α-平滑肌肌动蛋白(α-SMA)抗体进行免疫组织化学及免疫荧光化学染色。结果胚龄8-9 d,Shh阳性表达于前肠腹侧内胚层,Ptc1和Ptc2在心管心肌呈较强阳性表达,ISL-1阳性细胞自心包腔背侧壁、前肠两侧间充质延伸至心管动脉端。胚龄10-13 d,前肠内胚层向腹侧延伸形成喉气管沟,并呈Ptc1和Ptc2强阳性表达,ISL-1和Smo双阳性细胞围绕喉气管沟形成对称的锥体形结构,其顶端突入动脉囊腔,形成主肺动脉隔,随发育进行,主肺动脉隔由ISL-1阳性表达逐渐转为α-SMA强阳性表达,并将动脉囊分隔为MHC阴性的心包内升主动脉和肺动脉干。结论 Shh信号通路与ISL-1阳性细胞共同参与小鼠胚胎心流出道的正常形态发生。

Objective To explore the relationship of the early morphogenesis of the outflow tract in mouse embryonic heart with the expression of Sonic Hedgehog signaling members and ISL-1. Methods Serial sections of 40 mouse embryos from embryonic day（ ED） 8 to ED13 were stained by immunohistochemistry and immunofluorescence with antibodies against Shh,Smoothened,Patched,Patched2,ISL-1,MHC and α-SMA. Results At ED8 and ED9,Shh positive cells distributed in the forgut endoderm,Ptc1 and Ptc2 expressed strongly in the heart tube,and ISL-1 was detected in bilateral mesenchyme to the foregut,the splanchnic mesoderm of the pericardial cavity dorsal wall,and extended distally to the primary heart tube. From ED10 to ED13,the foregut endoderm extended ventrally to form laryngotracheal groove,Ptc1 and Ptc2 expressed strongly in the laryngotracheal groove,ISL-1 positive cells surrounding the laryngotracheal groove formed a symmetrical cone-shaped structure to form the aorta-pulmonary septum,the aorta-pulmonary septum was gradually transferred from ISL-1 positive expression to α-SMA positive expression,and the arterial sac was separated into MHC negative ascending aorta and pulmonary trunk. Conclusion Sonic Hedgehog signaling pathway and ISL-1 positive cells participate in the normal morphogenesis of outflow tract in mouse embryonic heart.