Dynamic analysis of Shh and specific receptor in embryologic process of anorectal malformations.

本研究的目的是确定类维生素A介导的信号通路在肛门直肠畸形（ARM）发病机制中的可能作用。为探讨全反式维甲酸（ATRA）对脊椎动物肛门直肠形态发生中重要的Sonic hedgehog（Shh）和骨形态发生蛋白（BMP）4表达的影响，在ICR系小鼠妊娠第9天（E9）给予全反式维甲酸100 mg/kg。在E12和E16之间从子宫获得给予或不给予ATRA的胚胎，并立即固定在4%多聚甲醛溶液中。冷冻切片通过II & E染色和免疫组织化学方法检测内胚层上皮周围的同心层。95%以上的ATRA胚胎具有ARM。在正常的后肠发育中，来自上皮的Shh诱导BMP 4在间充质中表达，间充质分化为固有层和粘膜下层。在ARM胚胎中，Shh和BMP 4的表达，这似乎在后肠的器官发生中起着至关重要的作用，在上皮细胞和间充质层之间的细胞信号通路中受到干扰。

The aim of this research was to determine the possible role of the retinoid-mediated signaling pathway in the pathogenesis of anorectal malformatins (ARM). We investigated whether all-trans retinoic acid (ATRA) affects the expression pattern of Sonic hedgehog (Shh) and Bone morphogenetic protein (BMP) 4, which play important roles in anorectal morphogenesis in vertebrates.Pregnant ICR strain mice were fed 100mg/kg of ATRA on the ninth gestigational day (E9). Embryos with or without administration of ATRA were obtained from the uteri between El2 and E16 and were fixed immediately in a 4% paraformaldehyde solution. Frozen sections were evaluated for concentric layers around the endodermal epithelium by II ＆ E stain and immunohistochemistry using antibodies created specifically to act against Shh and BMP4.More than 95% of the embryos administered ATRA had ARM. In normal hindgut development, Shh from the epithelium induces BMP4 expression in the mesenchyme, which differenciates into the lamina propria and the submucosa. In ARM embryos, expressions of Shh and BMP4, which appear to play a crucial role in organogenesis of the hindgut, were disturbed in the cell signaling pathway between the epithelium and the mesenchyme layers.