Disruption Of Hedgehog Signaling Pathway By GDC-0449 Leads To Cleft Palate In The Mouse

Cleft palate is a common congenital deformity around the world. Hedgehog signaling plays an important role in the development of embryo, especially in the development of palate. There is few report about the role of exogenous inhibitors in regulating the development of palate.Objective:To establish the high proportion of animal model of cleft palate by Hedgehog pathway inhibitor GDC-0449, and test defective cell proliferation and delayed palatine osteogenesis.Methods: C57BL/6J inbred pregnant mouse were randomly divided into test and control group. The mouse were fed with GDC-0449 on E10.5, E12.5, E10.5+E12.5.The test group of E10.5d were exposed to GDC-0449 in three different doses. We detected the occurrence of cleft palate at E16.5d in test and control group by HE staining technique. Timed pregnant mouse mice were killed sacrificed at E13.5, E14.5, E15.5 and E16.5, and embryos collected. Palatal shelf growth was evaluated by histological and immunohistochemical analyses as well as palatal organ culture. Immunohistochemical staining was performed to exam osteogenic protein expression in palatal tissue.Results: Twice 100mg/kg GDC-0449 administrated mice displayed a high proportion of cleft palate. Histologic examination revealed severely retarded palatal shelf growth with thickened epithelium in the experimental group. Our results showed a decreased rate of cell proliferation was decreased in the palatal mesenchyme of GDC-0449-treated mice. Moreover, this model also showed a delayed ossification in the region of palatine bone with the downregulation of Ihh protein.Conclusions: Our results suggest the importance of hedgehog signaling during palatal development. Under the action of exogenous hedgehog pathway inhibiter, the cell proliferation rate of the palatal shelves and osteogenic potential of the hard palate were decreased.