ABSTRACT
Objective To study the paracrine effect of hypoxic preconditioned umbilical cord mesenchymal stem cells (UCMSCs) on the proliferation,migration and osteogenic differentiation of osteoblasts.Methods UCMSCs were cultured under hypoxia and normal oxygen condition before two UCMSCs conditioned media were obtained.After that,MG-63 cells were cultured in three groups:hypoxia conditioned medium group,normoxia conditioned medium group and DMEM control group.The proliferation of MG-63 cells was detected by mosmann tetrazoline colorimetry( MTT) method after 1,3 and 5 days.The migratory ability of MG-63 cells was detected by scratch assay .After 21 days′culture , the formation of osteogenic calcium nodules was detected by Alizarin red staining.ELISA method was used to detect the content of vascular endothelial growth factor ( VEGF) in hypoxia and normoxia conditioned medium.Results The MTT test showed that the proliferation ability of MG-63 cells in hypoxia conditioned medium group and normoxia conditioned medium group was greater than in the DMEM control group.The difference was statistically significant ( P <0.05).Furthermore, the proliferation ability of cells in hypoxia conditioned medium group were much greater than cells in normoxia culture medium group.The difference was statistically significant (P<0.05).Scrath assay showed that the migratory ability of MG-63 cells in hypoxia conditioned medium group and normoxia conditioned medium group was greater than cells in DMEM control group,and cells in hypoxia conditioned medium group was much greater than cells in normoxia conditioned medium group. After 21 days′culture,we found that the number of calcium nodules was the largest in hypoxia conditioned medium group, followed by normoxia conditioned medium group and DMEM control group.ELISA showed that the content of VEGF in hypoxia conditioned medium was higher than that in normoxia conditioned medium and the difference was statistically significant (P<0.01).Conclusion The paracrine function of UCMSCs can be enhanced by hypoxia,thus improving the proliferation,migration and osteogenic differentiation of osteoblasts.