Genotoxicity of motorcycle exhaust particles in vivo and in vitro.
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.
Cheng
Yu Wen
YW
School of Pharmacy, Taipei Medical University, Taiwan.
Lee
Wen Wha
WW
Li
Ching Hao
CH
Lee
Chen Chen
CC
Kang
Jaw Jou
JJ
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*
D000975:Antioxidants; D009153:Mutagens; D017382:Reactive Oxygen Species; D001335:Vehicle Emissions