Effects of Caspase-3 and Caspase-8 on Sodium Fluoride-Induced Apoptosis in Human Neuroblastoma SH-SY5Y Cells

Objective To explore the effects of caspase-3 and caspase-8 on sodium fluoride(NaF)-induced apoptosis in human neuroblastoma SH-SY5Y cells. Methods The cell survival rate,percentage of apoptosis,caspase-3 activity and mRNA expression levels of caspase-3 and caspase-8 were determined respectively after the SH-SY5Y cells were exposed to 20,40 and 80 μg/ml NaF for 24 hours in vitro. Furthermore,the changes of the percentage of apoptosis,caspase-3 activity and mRNA expression levels of caspase-3 and caspase-8 in 40 μg/ml NaF-treated groups incubated with activating or neutralizing anti-Fas antibody (CH11 or ZB4) also were observed respectively. Results Compared with the control group,the cell survival rates in 40 and 80 μg/ml NaF-treated groups were significantly lower (P0.01). The percentage of apoptosis in 40 and 80 μg/ml NaF-treated groups were markedly higher than that in the control group (P0.05) and a dose-response trend was seen. The activity of caspase-3 and mRNA expression levels of caspase-3 and caspase-8 in 40 and 80 μg/ml NaF-treated groups were significantly higher than that in the control group (P0.05). CH11 showed a synergistic effect on fluoride-induced apoptosis when used in combination with NaF. ZB4 could partly block NaF-induced apoptosis of SH-SY5Y cells. Conclusion NaF can up-regulate the caspase-3 and caspase-8 expressions,which are the key enzymes of Fas pathway and subsequently promote apoptosis of SH-SY5Y cells.