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

本研究的目的是确定类维甲酸介导的信号通路在肛肠畸形（ARM）发病机制中的可能作用。我们研究了全反式维甲酸（ATRA）是否影响Sonic hedgehog （Shh）和Bone morphogenetic protein (BMP) 4的表达模式，这两种蛋白在脊椎动物肛肠形态发生中起重要作用。妊娠ICR品系小鼠在妊娠第9天（E9）饲喂100mg/kg的ATRA。在El2和E16之间的子宫中获得含有或未施用ATRA的胚胎，并立即固定在4%多聚甲醛溶液中。冷冻切片采用II & E染色和免疫组织化学方法对内胚层上皮周围的同心层进行评估，并使用专门针对Shh和BMP4的抗体。超过95%接受ATRA治疗的胚胎出现了ARM。在正常的后肠发育中，来自上皮的Shh诱导间质中BMP4的表达，并分化为固有层和粘膜下层。在ARM胚胎中，Shh和BMP4的表达在上皮和间质层之间的细胞信号通路中受到干扰，而Shh和BMP4似乎在后肠器官发生中起着至关重要的作用。

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.