Abstract: ObjectiveTo discuss the effect of N,N-dimethylformamide(DMF)at different dose and exposure time on Caspase-3's activation in normal human liver cells in vitro.MethodsThe human hepatocytes were exposed to DMF at the concentrations of 6.25,25,100 mmol/L for 12 hours.Then the hepatocytes were exposed to DMF at the concentration of 100 mmol/L for 0,3,6 and 12 hours.The control group was treated with phosphate buffered saline.Western blotting was performed to observe the activation of Caspase-3 in human hepatocytes.ResultsWith the increasing of DMF dose,the ratio of pro-Caspase-3's grey value showed a declined trendency on the whole but without statistical difference between different groups(F=1.363,P>0.05).Different dose of DMF could increase the activation of Caspase-3(F=7.684,P<0.01)with a tendency of increment with the increasing of dose.The average ratio of Caspase-3 subunits'grey value in 100 mmol/L group was the highest(0.55).With the increasing of exposure time,there was no statistical difference in pro-Caspase-3's grey value between different groups(F=0.490,P>0.05)with a declined trendency as the increasing of exposure.The ratio of Caspase-3 subunits'grey value significantly increased with the time of exposure(F=9.351,P<0.01)and the highest was 0.48 in the group of 12 hours'exposure.ConclusionActivation of Caspase-3 involves in the process of apoptosis induced by DMF in human hepatocytes and the activation level of Caspase-3 activation shows a good time-and dose-dependent relation with the exposure of DNF.