Apoptosis of Human Neuroblastoma SH-SY5Y Cells Induced by Sodium Fluoride

Objective To study the neurons damage and apoptosis induced by sodium fluoride(NaF) in human neuroblastoma SH-SY5Y cells and to explore the the potential mechanism of neurotoxicity of NaF.Methods SH-SY5Y cells of logarithmic phase(1×107/ml) were first incubated with fluoride(0,20,40,80 mg/L) and then with ethyleneglycol-bis-(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid(EGTA,380.40 mg/L),1,2-bis(O-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetra(acetoxymethyl) ester(BAPTA-AM,38.23 mg/L) alone or combined with fluoride(40 mg/L) respectively for 24 h in vitro.The cell viability was measured by MTT(thiazolyl blue).The percentage of apoptosis and intracellular calcium concentration i were measured by flow cytometry.Furthermore,laser scanning confocal microscope(LSCM) was used to test the change of intracellular free calcium concentration in single SH-SY5Y cells.Results Compared with the control group,the cell survival rates in 40 and 80 mg/L NaF-treated groups were significantly lower(P0.05).The percentage of apoptosis and i in 40 and 80 mg/L NaF-treated groups were higher(P0.05) than that in the control group,and increased as the dose of NaF increased.The study of laser scanning confocal microscope found that the increase of NaF concentration shortened the reaching peak time of i.Factorial analysis showed that intracellular calcium-chelating compound(BAPTA-AM) and NaF had interaction on apoptosis and the elevation of i(F=10.69,366.14,P0.05),BAPTA-AM could antagonize the cell injury caused by NaF in SH-SY5Y cells.Extracellular calcium chelator EGTA and NaF had no interaction.Conclusion NaF exposure could cause the elevation of calcium from the site of intracellular calcium storage,contributing to the damage and apoptosis induced by NaF.