A Research About The Influence Of Fluorides On Proliferation Activity And Secretory Function Of Ameloblasts

PurposeTo investigate the effects of fluorides on proliferation activity and secretory function of ameloblasts, and whether fluorides regulate amelogenesis by TGF-β1 mediated pathway.MethodsLS8(secretory-stage ameloblast) was treated with different concentrations of fluorides, and measured LS8 proliferation activity by CCK-8 at different time points, then the optimum concentrations were picked by the CCK-8 proliferation curve. Expressions of MMP20, KLK4 and TGF-β1 were detected in LS8 which was exposed to the optimum concentrations of fluorides for 24h. MMP20 expression of LS8 were detected after regulating TGF-β1 mediated pathway. All data was calculated by SPSS 17.0.Results1.There were no significant differences among proliferation activity of LS8 with short-term fluoride treatment; as acting periods prolonged, different concentrations of fluorides made different effects; the longer time it worked, the stronger toxity it had.2. At the time point of 24h, low dose fluorides(< 1.OmM) promoted LS8 proliferation activity, and 0.25mM made the strongest effect; high dose fluorides(>1.0mM) inhibited LS8 proliferation activity; the effect of 1.OmM was similar to that of the control group.3. At the time point of 24h, low dose fluorides(<1.0mM) increased expressions of MMP20, KLK4 and TGF-β1; high dose fluorides(> 1.OmM) inhibited expressions of MMP20, KLK4 and TGF-β1; the variation trends of these three were similar.4. Exogenous TGF-β1 increased MMP20 expression; the higher TGF-β1 concentration was, the more MMP20 expressed.5. MMP20 expression of LS8 treated with exogenous TGF-β1 and high dose fluoride was higher than that of LS8 treated with only high dose fluoride.6. TGF-β1 receptor inhibitor LY2157299 inhibited MMP20 expression; combination of LY2157299 and TGF-β1 made a lower MMP20 expression than single TGF-β1 treating group.ConclusionAs the pathogenic factor of dental fluorosis, fluorides may directly affect amelogenesis by regulating secretory-stage ameloblasts proliferation activity; it may also indirectly affect amelogenesis by inhibiting MMP20 expression; fluorides regulate amelogenesis via TGF-β1 mediated pathway.Short-term action of low dose fluorides may protect teeth from caries, and increase proliferation activity and secretory function of ameloblasts; otherwise it may inhibit amelogenesis, and induce dental fluorosis. Proper application of fluorides make great sense in descreasing caries prevalence rate, and keeping human oral health. The effect of TGF-β1 against fluoride toxity may help preventing and curing dental fluorosis as a important supplementary method.