Dhcr7 Regulates Palatal Shelf Fusion through Regulation of Shh and Bmp2 Expression.

The aim of this study was to investigate the effect of the 7-dehydrocholesterol reductase (Dhcr7) gene and identify signaling pathways involved in regulation of embryonic palatogenesis. The expression of Dhcr7 and its protein product were examined during murine normal embryonic palatogenesis via a reverse transcription polymerase chain reaction (RT-PCR) and Western blot (WB). RNA interference (RNAi) technology was used to inhibit Dhcr7 expression in a palatal shelf culture in vitro. The effects of Dhcr7 on palatogenesis and palatal fusion were examined by scanning electron microscopy (SEM). The expression changes of Dhcr7, Sonic Hedgehog (Shh), and bone morphogenetic protein-2 (Bmp2) were measured by RT-PCR and WB after Dhcr7 gene silencing and the addition of exogenous cholesterol. The results showed that the palatal shelf failed to complete normal development and fusion when Dhcr7 expression was inhibited. The inhibitory effect study of RNAi on the development of the palatal shelf supported that cholesterol supplementation did not alter the silencing of Dhcr7. Shh and Bmp2 expressions were reduced after Dhcr7 gene silencing, and administration of exogenous cholesterol did not affect Dhcr7 expression; however Shh and Bmp2 expressions increased. We conclude that Dhcr7 plays a role in growth of the palatal shelf and can regulate palatogenesis through alterations in the levels of Shh and Bmp2.

[Establishment of palatal organ culture model of C57BL/6J mouse embryos in vitro].

PURPOSE: To establish palatal organ culture model of C57BL/6J mouse embryos in vitro and provide platform for study of embryo palatal development. METHODS: The mouse palatal shelves were harvested under sterilization from a female mouse of gestation day(GD) 13.5 by stereoscopic microscope and cultured in vitro. Totally 36 pairs of palatal shelves were divided into three groups equally and cultured 6 h, 24 h and 48 h, respectively. Finally, all palatal shelves were embedded and stained by Hematoxylin and Eosin (HE) and subjected to scanning electron microscope (SEM) analysis. RESULTS: The results of HE dyeing showed that the palatal shelves did not fuse on 6 h group, and began to fuse on 24 h group, but still had some medial edge epithelial (MEE) cells remained. The palatal shelves completely fused and all the MEE cells disappeared on 48 h group. The results of SEM showed that there was a gap between palatal shelves on 6 h group. The palatal shelves began to contact and form the medial epithelial seam (MES) on 12 h group. Finally, palatal shelves completely fused and MES disappeared on 48 h group. CONCLUSION: This method provides an effective way for investigating the etiology of cleft palate in vitro.