目的

探讨维甲酸对不同时期小鼠胚胎腭突区Bmpr-1b 表达的影响。

方法

采用100 mg/kg 全反式维甲酸（atRA）在C57BL/6N 近交系孕鼠妊娠第10 天（GD10）给予灌胃，对照组纯玉米油灌胃。 GD13、GD15、GD17 时取出胚胎并暴露胎鼠腭突，进行苏木精-伊红（HE）染色，并对3 个时期的胚胎腭样本进行免疫组织化学染色，检测Bmpr-1b 在不同组内小鼠胚胎腭突组织内的表达。 在GD15 和GD17 时按照上述方法取孕鼠的胚胎腭部组织进行反转录聚合酶链反应（RT-PCR）检测Bmpr-1b 的mRNA 表达。

结果

HE 染色观测发现实验组腭突没有在中线处融合，形成体积较小的畸形腭突和明显的中缝腭裂，成骨中心区范围明显小于对照组。 免疫组织化学检测发现，Bmpr-1b的表达与腭突间充质组织的生长发育呈正相关。 GD13 ～GD17 期间实验组小鼠发育中的腭突间充质中Bmpr-1b 的阳性指数得分均少于对照组。 GD17 时期实验组小鼠腭突间充质组织的骨组织支架面积小于对照组。 RT-PCR 结果显示，GD17 时期Bmpr-1b 的mRNA 表达水平均显著高于GD15。 在同一时间点内，对照组的Bmpr-1b 的表达水平显著高于实验组。

结论

对GD10 C57BL/6N 母鼠进行atRA 灌胃可导致胎鼠腭突区Bmpr-1b 的表达水平明显下调，腭突发育不良，腭部骨骼形成进程都受到抑制，最终形成小腭突畸形。

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.