Objective To test the effects of sodium fluoride (NaF) on apoptosis of osteoblasts MC3T3-E1.
Methods MC3T3-E1 cells were exposed to different doses of NaF for 24 h and 48 h, respectively. Cell viability was measured by CCK-8 to determine exposure concentrations and time for subsequent experiment. The osteoblasts were treated with 0, 1×103, 2× 103, and 3×103μmol/L NaF for 24 h and 48 h, respectively. Apoptosis was detected by flow cytometry. The expressions of Caspase-3 and Caspase-8 mRNA were detected by real-time PCR and the expression of Cleaved Caspase-3 and Cleaved PARP proteins were detected by Western blot.
Results The results of CCK-8 assay showed that the survival rate of MC3T3-E1 cells decreased with the increase of NaF concentration and the prolongation of exposure time. At 1×103μmol/L, the OD value of CCK-8 assay was lower than that of the control group, and the survival rate decreased (P < 0.05). The OD value at 1×103μmol/L for 48 h was also lower than that for 24 h (P < 0.05). Compared with the control group, the apoptosis rates at different stages at 24 h of the NaF treatment groups were significantly higher than that of the control group (P < 0.05), except the apoptosis rate at middle and late stages of the 1×103μmol/L NaF group. The expression levels of Caspase-3 and Caspase-8 mRNA showed an increasing trend with the increasing concentration of NaF; and the expression levels of Cleaved Caspase-3 and Cleaved PARP also increased in all NaF groups (P < 0.05), except the expression of Cleaved PARP protein of the 1×103μmol/L NaF group.
Conclusion The signal transduction mediated by Caspase plays an important role in the apoptosis induced by high concentration of sodium fluoride.
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