OBJECTIVERNA interference was applied to knockdown the Dhcr7 gene in mouse embryonic palatal shelves to facilitate understanding of the function of Dhcr7 gene variants in the fusion of palatal shelves.

METHODSThe pAdTrack-CMV-siDhcr7 was constructed using the specific siRNA sequence of Dhcr7 from C57BL/6J mouse. The pAdTrack-CMV- siDhcr7 of positive clones was reconstructed in vitro, and the recombinant adenovirus pAdEasy-1-siDhcr7 of kanamycin resistance was screened. The adenovirus vector DNA was then prepared for transfecting the embryonic palatal shelves. Thirty pairs of embryonic palatal shelves at 13.5 d gestational age were harvested and then randomly divided into the following three groups: normal control group (n = 10), which included palatal shelves inculture medium without cholesterol; blank adenovirus control group (n = 10), which included palatal shelves in culture medium without cholesterol and blank adenovirus; and experimental group (n = 10), which included palatal shelves in culture medium without cholesterol and adenovirus encoding Dhcr7 siRNA. At 48 h after in vitro cultivation, the mRNA and protein of the palatal shelves were obtained for scanning electron microscopy (SEM), reverse transcription polymerase chain reaction (RT-PCR), and Western blot analyses.

RESULTSSEM showed that the palatal shelves of the normal control and blank adenovirus control groups fused and formed continuous palates, whereas those of the experimental group was almost undeveloped but exhibited large gaps between the two palatal shelves. RT-PCR and Western blot analyses showed that the mRNA and protein of Dhcr7 in the experimental group decreased compared with those in the normal control group with a significant difference (P < 0.05).

CONCLUSIONResults indicate that Dhcr7 gene silencing affects the fusion of palatal shelves. Thus, Dhcr7 gene may serve a function in the normal development of palates.

Animals ; Cleft Palate ; Gene Silencing ; Mice ; Mice, Inbred C57BL ; Microscopy, Electron, Scanning ; Organ Culture Techniques ; Oxidoreductases Acting on CH-CH Group Donors ; Palate ; growth & development ; RNA, Messenger

OBJECTIVETo investigate the effect of 7- dehydrocholesterol reductas (Dhcr-7) gene silencing on the palatal development by sonic hedgehog (Shh)-bone morphogenetic protein2(BMP-2) signal pathway in vitro.

METHODSA total of 60 pairs of palatal shelves fromgestation day (GD) 13.5 mouse embryos were divided into three groups (A, B, C) of 20 randomly. In group A (control), palatal shelves were cultured with medium containing no cholesterol.In group B (Dhcr-7-siRNA), palatal shelves were cultured without cholesterol medium but containing Dhcr-7 siRNA adenovirus. After 48h, the culture medium of groups A and B were changed with medium without cholesterol. In group C (cholesterol), palatal shelves were cultured without cholesterol medium but containing Dhcr-7 siRNA adenovirus. After 48h, the culture medium of group C was changed with medium containing 600 mg/L cholesterol. After 72h again, tissues dyeing and scanning electron microscope (SEM) technique were used to observe morphological changes of palates. Both RT-PCR and Western blottingtechniques were used to measure mRNA and protein expressions for Dhcr-7, Shh, and BMP-2, respectively.

RESULTSThe tissues dyeing and SEM showedthat the palates fusedin groups A and Candthe palates did not fuse in group B eventually. The expression of both mRNA and proteins for Shh and BMP-2 in group B wasdecreased with the Dhcr-7 reduction. In group B, the mRNA and protein expression of Shh was separately 0.063±0.018 and 0.092±0.065;the mRNA and protein expression quantity of BMP- 2 was separately 0.054±0.018 and 0.049±0.021. In group A, the mRNA and protein expression of Shh was separately 0.667±0.093 and 0.639±0.078;the mRNA and protein expression of BMP-2 was separately 0.591 ± 0.043 and 0.569 ± 0.081. The difference of Shh and BMP- 2 mRNA and protein expression between A and B group were statistically significant separately (P < 0.05). The expression of both mRNA and protein for Dhcr-7 (0.074±0.034 and 0.075±0.028) did not changebasicallyin group C, compared with the Dhcr- 7expression of mRNA and protein (0.083±0.045; 0.067±0.065) in group B, the difference wasnot statistically significant(P > 0.05). In group C, the mRNA and protein expressionof Shh (0.649±0.085 and 0.608±0.092) and BMP-2 (0.578±0.062 and 0.548±0.065) were significantly increased. The difference of Shh and BMP-2 mRNA and protein expression between B and C group were statistically significant separately (P < 0.05).

CONCLUSIONSDhcr-7 could influence the expression of Shh and BMP-2. Dhcr-7 reductase regulated the palatal development by the Shh-BMP-2 signal pathway.

Animals ; Bone Morphogenetic Protein 2 ; genetics ; metabolism ; Cholesterol ; Culture Media, Conditioned ; chemistry ; pharmacology ; Hedgehog Proteins ; genetics ; metabolism ; Mice ; Oxidoreductases Acting on CH-CH Group Donors ; metabolism ; Palate ; growth & development ; metabolism ; RNA, Messenger ; analysis ; metabolism ; RNA, Small Interfering ; metabolism ; Random Allocation ; Signal Transduction