Effect of NaF on apoptosis in human osteoblast-like cell line

  Objective   To study the apoptotic effect of sodium fluoride(NaF)and its mechanisms in human osteoblast cell line OS-732.

  Methods   The effects of NaFon osteoblast cell proliferation and apoptosis were detected by methyl thia zolyl tetrazolium(MTT), Hoechst33342 fluorescence staining, agarose gel electrophoresis, flow cytometry(FCM), semi-quantitative RT-PCR and caspase-3 activity assays.

  Results   After cells were treated with NaF(4, 6, 8×10^-3 mol/L)for 24 h, the proliferation of OS-732 cells measured by MTT methods was inhibited in a dose dependent manner(P < 0.01).The morphological changes and the apoptotic peaks were observed by fluorescence staining and FCM respectively.In addition, the expression of Bcl-2 mRNA decreased whereas the expression of Bax mRNA increased measured by semi-quantitative RT-PCR.The activity of Caspase-3 also increased after cells were treated with NaF(6×10^-3 mol/L)for 24h(P < 0.01).Finally, DNA fragmentation was observed when cells were treated with NaF(4, 6, 8×10^-3 mol/L)for 48 h.

  Conclusion   NaF inhibited the proliferation of osteoblast cell line OS-732 and induced the cells to undergo apoptosis by increasing the activity of caspase-3, and the expression of Bax while decreasing the expression of Bcl-2.