RESUMEN
Objective Micronucleus test(MNT) was used to evaluate the single and combined genotoxicity of dichlorvos(DDVP),dimethoate(DM) and malathion(Mal) in HepG2 cell line,and 2?2 factorial design was adopted to elucidate the combined genotoxic effects.Methods In cytotoxicity test,HepG2 cells were exposed to the three OPPs(DDCP,DM,Mal) for 4 h respectively,and the doses at which cell viability above 80% were selected for the MNT,DDVP:3.125-25 ?g/ml,DM:25-200 ?g/ml,Mal:50400 ?g/ml,the micronucleated cell(MNC) rates and the replicative index(RI) were calculated.The combined genotoxicity of them was investigated with their doses as follows:low dose(DDVP:3.125 ?g/ml,DM:25 ?g/ml,Mal:50 ?g/ml);high dose(DDVP:12.5 ?g/ml,DM:100 ?g/ml,Mal:200 ?g/ml).Results In MNT,after treatment of HepG2 cells with DDVP,DM or Mal alone for 4 h,the MNC rates were increased in a dose-response manner(DDVP:r=0.955,P