Oxidative stress and DNA damage caused by the urban air pollutant 3-NBA and its isomer 2-NBA in human lung cells analyzed with three independent methods.
The air pollutant 3-nitrobenzanthrone (3-NBA), emitted in diesel exhaust, is a potent mutagen and genotoxin. 3-NBA can isomerise to 2-nitrobenzanthrone (2-NBA), which can become more than 70-fold higher in concentration in ambient air. In this study, three independent methods have been employed to evaluate the oxidative stress and genotoxicity of 2-NBA compared to 3-NBA in the human A549 lung cell line. HPLC-EC/UV was applied for measurements of oxidative damage in the form of 8-oxo-2'-deoxyguanosine (8-oxodG), (32)P-HPLC for measurements of lipophilic DNA-adducts, and the Comet assay to measure a variety of DNA lesions, including oxidative stress. No significant oxidative damage from either isomer was found regarding formation of 8-oxodG analysed using HPLC-EC/UV. However, the Comet assay (with FPG-treatment), which is more sensitive and detects more types of damages compared to HPLC-EC/UV, showed a significant effect from both 3-NBA and 2-NBA. (32)P-HPLC revealed a strong DNA-adduct formation from both 3-NBA and 2-NBA, and also a significant difference between both isomers compared to negative control. These results clearly show that 2-NBA has a genotoxic potential. Even if the DNA-adduct forming capacity and the amount of DNA lesions measured with the (32)P-HPLC and Comet assay is about one third of 3-NBA, the high abundance of 2-NBA in ambient air calls for further investigation and evaluation of its health hazard.
Nagy
Eszter
E
Department of Biosciences at Novum, Karolinska Institutet, SE-141 57 Huddinge, Sweden.
Johansson
Clara
C
Zeisig
Magnus
M
Möller
Lennart
L
D000080242:8-Hydroxy-2'-Deoxyguanosine; D000393:Air Pollutants / Q000633:toxicity*; D001551:Benz(a)Anthracenes / Q000633:toxicity*; D002460:Cell Line; D002851:Chromatography, High Pressure Liquid; D020552:Comet Assay; D004249:DNA Damage; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000032:analysis; D006801:Humans; D008168:Lung / Q000187:drug effects*; D018384:Oxidative Stress; D010761:Phosphorus Radioisotopes
D000393:Air Pollutants; D001551:Benz(a)Anthracenes; D010761:Phosphorus Radioisotopes; D000080242:8-Hydroxy-2'-Deoxyguanosine; D003849:Deoxyguanosine; C117220:3-nitrobenzanthrone