同源异型盒基因MSX-2在SD大鼠颅缝闭合过程中的表达

Expression of homeobox gene MSX-2 during cranial suture fusion of SD rats

目的研究同源异型盒基因Msx-2在SD大鼠颅缝闭合过程中的表达变化及意义。方法选择出生后1、2、5、8、12、15、18、22、30和45 d的SD大鼠,采用免疫组化和Real-timePCR法分别检测颅缝不同位点的MSX-2表达。结果MSX-2表达于SD大鼠发育的颅骨成骨缘、颅缝间质及其下的硬脑膜组织。在后额缝和矢状缝均未闭合期(出生后1～8 d),后额缝和矢状缝复合组织中均出现MSX-2少量表达;在活跃的后额缝闭合期(出生后12～22 d),后额缝复合组织出现较多MSX-2表达,而矢状缝复合组织无明显的表达增加;在后额缝完全闭合期(出生后30～45 d),MSX-2表达在后额缝减弱明显,并持续较低水平,此时矢状缝的表达略高于后额缝。结论同源异型盒基因MSX-2转录主要发生于颅缝闭合活跃阶段,在后额缝和矢状缝复合组织的表达有不同的时间趋势,提示可能参与颅骨发育和颅缝闭合的调控。

Objective To investigate the expression of homeobox gene MSX-2 during cranial suture fusion of SD rats and discuss its significance. Methods SD rats aged 1, 2, 5, 8, 12, 15, 18, 22, 30 and 45 days were selected, and immunohistochemistry and Real-time PCR were employed to localize and quantify the expression of MSX-2 in different regions of cranial sutures. Results MSX-2 expressed in ealvarial suture tissues including the extreme ends of the osteogenic fronts and the underlying dura mater. The expression of MSX-2 was low in posterior frontal suture （PF） and sagittal suture （SAG） from postnatal day 1 to day 8 before the initiation of suture fusion, while it was higher in PF than in SAG from postnatal day 12 to day 22 after the initiation of PF suture fusion. The expression of MSX-2 significantly declined in PF and was moderately higher than that in SAG from postnatal day 30 to day 45 after the initiation of suture fusion. Conclusion There is different expression of MSX-2 in PF and SAG during different suture fusion periods, which suggests the expression of MSX-2 may participate in the regulation of cranial bone development and the fusion of cranial sutures.