Abstract:

Objective

To investigate the effects of RA on palatogenesis and the role of Bmpr-1b expression in embryonic palate of mice at different stage.

Methods

atRA （100 mg/kg b.w.） was given to GD10 pregnant C57BL/6N female mice by gastric intubations. Control animals were given the equivalent volume of olive oil. On GD13， 15 and 17 respectively， the pregnant mice were killed to obtain the embryos from the uteri. The embryonic palates were staining with Harris's haematoxylin and 1% aqueous eosin （HE）. The remaining sections were used for immunohistochemistry of Bmpr-1b detection. Dissected palatal shelves （PS） were collected on GD15 and GD17 and RT-PCR was performed to detect the expression levels of Bmpr-1b.

Results

In the atRA-treated group， the PS showed short extensions and failed to fuse with each other. Compared with those of the control group，the zone of ossification of PS in atRA-treated group was smaller， and the intense staining of Bmpr-1b located in the mesenchymal cells was less from GD13 to GD17. Moreover the area of developing palatal process of the palatine bone was smaller in atRA-treated group on GD17. RT-PCR analysis demonstrated that the expressions of Bmpr-1b were more pronouncedly identified in the control groups when compared to the atRA-treated groups.

Conclusion

Treatment of pregnant mice with RA on GD10 produces small palatal shelves in their fetuses and down-regulate Bmpr-1b expressions， then retreat palatogenesis progresses including palatal skeletogenesis.

Key words: Retinoic Acid, Cleft palate, Signal pathway, Bmpr-1b