Effect of Trichlorfon on Proliferation and Differentiation of SH-SY5Y Human Neuroblastoma Cells

Objective To investigate further the neurotoxicity of chemical insecticide trichlorfon(TCL) and to determine the effects of TCL on neuroblastoma cell proliferation and differentiation.Methods SH-SY5Y cells were treated with 0~500 μmol/L TCL for 24 h or 48 h,and the cell viability was determined using MTT assay.Cell differentiation was induced by 20 μmol/L ATRA and cell was co-treated with 100 μmol/L TCL,then,the neural process of long length and cell size ratio were observed to assess the level of cell differentiation using inverted microscope.The growth inhibitory effec of TCL(100 μmol/L,200 μmol/L) for 24 h or 48 h on cell cycle progression/apoptosis were assessed by Flow Cytometry. Results TCL significantly inhibited the proliferation and growth of SH-SY5Y cells in a dose-effect and time-effect relationship.The 50% inhibiting concentration(IC50) of TCL exposure for 24 h and 48 h were 225 μmol/L and 177 μmol/L respectively.In addition,there were no increase of sub-G1 peak in all tested cells,indicating the cells did not undergo apoptosis even after 24 or 48 hour exposure to TCL.Cell differentiation assay found that TCL treatment of neural processes were less long than non-treated controls,suggesting TCL inhibiting the growth of axons.Flow Cytometry analysis showed that,TCL(100 μmol/L,200 μmol/L) had a significant impact on the cell cycle progression,arresting at the G2/M phase,compared with non-treated controls after 24 h of incubation.Conclusion TCL may be able to inhibit the growth of axons,The suppressive effect of TCL at high concentration was associated with G2/M stage arrest in SH-SY5Y cells.