title: Genotoxicity of motorcycle exhaust particles in vivo and in vitro.
abstract: We studied the genotoxic potency of motorcycle exhaust particles (MEP) by using a bacterial reversion assay and chromosome aberration and micronucleus tests. In the bacterial reversion assay (Ames test), MEP concentration-dependently increased TA98, TA100, and TA102 revertants in the presence of metabolic-activating enzymes. In the chromosome aberration test, MEP concentration-dependently increased abnormal structural chromosomes in CHO-K1 cells both with and without S9. Pretreatment with antioxidants (alpha-tocopherol, ascorbate, catalase, and NAC) showed varying degrees of inhibitory effect on the MEP-induced mutagenic effect and chromosome structural abnormalities. In the in vivo micronucleus test, MEP dose-dependently induced micronucleus formation in peripheral red blood cells after 24 and 48 h of treatment. The increase of micronucleated reticulocytes induced by MEP was inhibited by pretreatment with alpha-tocopherol and ascorbate. The fluorescence intensity of DCFH-DA-loaded CHO-K1 cells was increased upon the addition of MEP. Our data suggest that MEP can induce genotoxicity through a reactive oxygen species-(ROS-) dependent pathway, which can be augmented by metabolic activation. Alpha-tocopherol, ascorbate, catalase, and NAC can inhibit MEP-induced genotoxicity, indicating that ROS might be involved in this effect.
authors.affiliation: School of Pharmacy, Taipei Medical University, Taiwan.
authors.forename: Yu Wen
authors.initials: YW
authors.lastname: Cheng
authors.forename: Wen Wha
authors.initials: WW
authors.lastname: Lee
authors.forename: Ching Hao
authors.initials: CH
authors.lastname: Li
authors.forename: Chen Chen
authors.initials: CC
authors.lastname: Lee
authors.forename: Jaw Jou
authors.initials: JJ
authors.lastname: Kang
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D016466:CHO Cells; D002869:Chromosome Aberrations / Q000187:drug effects; D006224:Cricetinae; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry; D066298:In Vitro Techniques; D008099:Liver / Q000378:metabolism; D015162:Micronucleus Tests; D009049:Motorcycles; D009152:Mutagenicity Tests; D009153:Mutagens / Q000633:toxicity*; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000737:chemistry; D012486:Salmonella typhimurium / Q000235:genetics; D013347:Subcellular Fractions / Q000187:drug effects; D001335:Vehicle Emissions / Q000032:analysis / Q000633:toxicity*
chemical_list: D000975:Antioxidants; D009153:Mutagens; D017382:Reactive Oxygen Species; D001335:Vehicle Emissions