Detection for DNA Damage in Human Lymphocytes Induced by Four Chemicals Using Comet Assay

Objective To validate feasibility of comet assay as a tool for detecting DNA damage induced by various types of chemical mutagens.Study of DNA damage induced by4chemicals on human lymphocytes was carried out in vitro.Methods Human lymphocytes were exposed to4-nitroquinoline-1-oxide(4NQO,a UV-mimetic agent ),methyl methanesulfonate(MMS,an alkylating agent ),Bleomycin(BLM,a radiamimetic agent )and Mitomycin(MMC,a DNA crosslink agent )for3h,the DNA single strand breaks(SSB)induced by4chemicals were measured immediately(0h-incubation)and21h-incubation after3h-exposure to the chemicals with comet assay.Results It was found that the SSB induced by4NQO,MMS and BLM,which revealed a dose-response relationship(P0.01),could be detected immediately after the3h-exposure with comet assay,and the SSB diminished at the end of21h-incubation after the exposure(comparing with0h-incubation,P0.01).The SSB induced by MMC could not be detected until21h after exposure with comet assay,and also showed a dose-response relationship(P0.01).Con clusion Although the mutagenic mechanisms of4chemical mutagens were different,their DNA damage effects on human lymphocytes could be detected with comet assay.