ABSTRACT
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 calvarial 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.