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 NaF on osteoblast cell proliferation and apoptosis were detected by methyl thiazolyl 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(P0.01).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(P0.01).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.