[Effect of zinc ion on the expression of osteoblastic proteins in MC3T3-E1 cells in inflammatory environment]

To investigate the effect of zinc ion on the expression of osteoblastic proteins.

Mice osteoblasts MC3T3-E1 cells were subcultured. Inflammatory environment model was established by tumor necrosis factor α(TNF-α)at a concentration of 10 mg/L. According to different concentration of Zn(2+), the cells were divided into TNF-α group, control group, group A(TNF-α+10(-4) mol/L Zn(2+)), group B(TNF-α+10(-5) mol/L Zn(2+)), group C(TNF-α+10(-6) mol/L Zn(2+)). After 24, 48, and 72 h of culture, cell counting kit-8(CCK-8)assay was used to analyze the proliferation of the cells. ALP activity was examined. Bone morphogenetic protein-2(BMP-2), Runt-related transcription factor 2(RUNX2), Osterix and receptor activator of NF-κB ligand(RANKL)protein levels were determined by Western blotting after 72 h of culture.

The cells grew by adherence after 24 h. After 72 h, the cells grew dense, and the cells showed long spindle shape or irregular shape. The proliferation of osteoblasts in TNF-α group, group B and group C became lower than that in the control group(P<0.05), and was not significantly different between group A and the control group(P >0.05). ALP activity examination demonstrated that the groups cultured for 72 h revealed the highest ALP activity and the most prominent differentation compared with 24 h and 48 h groups. ALP activity was significantly decreased in TNF-α group, group B and group C compared with control group(P<0.05), but was not significantly different between group A and control group(P>0.05). The protein levels of BMP-2, RUNX2 and Osterix were significantly decreased in TNF-α group, group B and group C compared with control group(P<0.05), while showed no significant difference between group A and the control group. Protein level of RANKL was significantly increased in TNF-α group, grope B and group C compared with control group(P<0.05), while showed no significant difference between group A and control group.

The concentration of 10(-4) mol/L Zn(2+) can significantly increase the expression of osteoblastic proteins such as ALP, BMP-2, RUNX2, Osterix and decrease the expression of RANKL in mice osteoblasts in TNF-α inflammatory environment.