Formation of DNA adducts and oxidative DNA damage in rats treated with 1,6-dinitropyrene

In vitro metabolism studies have indicated that the tumorigenic environmental pollutant 1,6-dinitropyrene has the potential to bind covalently to DNA and to induce oxidative DNA damage. We have determined if 1,6-dinitropyrene treatment will cause both types of DNA damage in vivo. Female Sprague-Dawley rats were given a single intraperitoneal injection of 1,6-dinitropyrene, and covalent DNA adduct formation, as indicated by the presence of N-(deoxyguanosin-8-yl)-1-amino-6-nitropyrene, and oxidative DNA damage, as indicated by increases in 5-hydroxymethyl-2'-deoxyuridine and 8-hydroxy-2'-deoxyguanosine, were assessed at 3, 12, 24 and 48 h after dosing. 32P-postlabeling analyses of DNA isolated from liver, mammary gland, bladder and nucleated blood cells indicated the formation of N-(deoxy-guanosin-8-yl)-1-amino-6-nitropyrene, with the levels being highest in the bladder. 5-hydroxymethyl-2'-deoxyuridine was detected in DNA from each of these tissues, and the levels of this oxidized nucleoside were higher in the mammary glands and livers of 1,6-dinitropyrene-treated rats. 1,6-Dinitropyrene dosing did not affect the levels of 8-hydroxy-2'-deoxyguanosine in these two tissues. These results indicate that exposure to 1,6-dinitropyrene can result in increased levels of 5-hydroxymethyl-2'-deoxyuridine in addition to covalent DNA adduct formation.