[Effect of fluoride on the viability and apoptosis of ameloblasts in vitro].

PURPOSE: To evaluate the effect of fluoride on viability of rat ameloblasts in vitro. METHODS: The ameloblasts of rat was exposed to different concentrations of NaF (0, 0.4, 0.8, 1.6, 3.2, 6.4 mmol/L) for 24, 48 and 72 hours. CCK-8 assays were performed to measure the cells proliferation; The morphology of apoptosis was observed by Hoechst 33258 staining and the rate of apoptosis was determined by flow cytometry. The data was analyzed using SPSS 13.0 software package. RESULTS: (1)The proliferation of ameloblasts was increased when concentrations of NaF between 0.4 mmol/L and 0.8 mmol/L, whereas inhibited at 1.6 mmol/L NaF and above. The effects were in time-dependent manner.(2)Cells in the 1.6 mmol/L NaF groups showed unclear karyorrhexis and apoptotic cell morphology. The effects were in concentration-dependent manner. CONCLUSIONS: (1)Fluoride has two-phase effects to ameloblasts: At low doses, it promoted cell proliferation while at high doses it had negative effects. (2)1.6 mmol/L NaF could induce apoptosis of ameloblasts.