Abstract: Objective To assess the toxic effect and its mechanism of 2,2',4,4',5,5'-hexachlorobiphenyl(PCB153) on pancreatic β-cell line(INS-1) cells.Methods INS-1 cells were exposed to PCB153(1,3,and 6 μmol/L) in vitro.Dimethyl sulfoxide(DMSO) was used as solvent control.After 24 hours,the rate of cellular survivors,percentage of apoptosis,intracellular reactive oxygen species(ROS) level,and expression levels of caspase 3 and caspase 12 genes were measured,respectively.Results Compared with the control group,the rate of cellular survivors in 3 μmol/L PCB153-treated group(80.9±8.7%) and 6 μmol/L PCB153-treated group(42.2±4.3%) were significantly decreased(P<0.05).The ROS levels and percentages of apoptosis in 3 μmol/L PCB153-treated group(fluorescence intensity:9.2±0.4,percentage of apoptosis:30.7±3.4%) and 6 μmol/L PCB153-treated groups(fluorescence intensity:3.7±1.6,percentage of apoptosis:40.4±1.3%) were notably higher than those of in the control group(P<0.05 for all).The expression levels of the caspase 3 in 6 μmol/L PCB153-treated group and caspase 12 in 3 μmol/L and 6 μmol/L PCB153-treated groups were significantly increased than those in the control group(P<0.05).ConclusionPCB153 may induce the apoptosis of INS-1 cells,and the oxidized stress and the endoplasmic reticulum signal passage may play an important role in the apoptosis induced by PCB153.