Improvement in the Diagnostic Potential of (32)P-Postlabeling Analysis Demonstrated by the Selective Formation and Comparative Analysis of Nitrated-PAH-Derived Adducts Arising from Diesel Particle Extracts

摘要

Studies suggest that DNA adducts derived from N-substituted aryl-compounds are poorly recovered in the nuclease P1 version of the (32)P-postlabeling assay but not the butanol extraction version. Both versions were employed to ascertain whether the differences in sensitivity could be used to select for nitroaromatic-DNA adducts derived by treating calf thymus DNA with organic extracts from four diesel and one gasoline vehicle emission particles. The authors' enhanced the formation of nitrated-PAH-derived adducts through xanthine oxidase-catalyzed nitroreduction of nitrated-polycyclic aromatic hydrocarbons; constituents previously detected in the diesel emissions. All four diesel organic extracts treated with xanthine oxidase resulted in the formation of one major DNA adduct chromatographically distinct from the multiple DNA adducts detected in the rat liver S9-treated incubations. The adduct was detectable with the butanol extraction but not the nuclease P1 version of the (32)P-postlabeling assay and was chromatographically similar to DNA adducts formed following xanthine oxidase nitroreduction of 1-nitropyrene or ascorbic acid treatment of 1-nitro-8-nitrosopyrene and 1-nitro-6-nitrosopyrene.