DNA damage and repair, oxidative stress and metabolism biomarker responses in lungs of rats exposed to ambient atmospheric 1-nitropyrene

1-Nitropyrene (1-NP) is a mutagenic and carcinogenic pollutant very widespread in the environment. However, the relative investigations on genotoxicity, oxidative stress and metabolic enzymes in lungs of mammalian caused by 1-NP have not been fully established. In this study, the 1-NP solutions at 3 dosages (1.0 × 10⁻⁵, 4.0 × 10⁻⁵ and 1.6 × 10⁻⁴ mg/kg body weight) were respectively given to rats by the intratracheal instillation. The responses of 1-NP on DNA damage and repair, oxidative stress and metabolism biomarkers in rat lungs after exposure to 1-NP were measured. The results showed 1-NP at three dosages induced obvious DNA strand breaks, 8-OH-dG formation and DNA-protein cross-link in rat lungs compared with the control. Higher dosage 1-NP (4.0 × 10⁻⁵ and 1.6 × 10⁻⁴ mg/kg body weight) greatly activated DNA repair gene OGG1 and inhibited MTH1 and XRCC1 expressions, and they significantly elevated the levels of GADD153, heme oxygenase-1 and malondialdehyde and decreased SOD activity, accompanied by the increases of CYP450, CYP1A1, CYP1A2 and GST levels. These results suggested the genotoxicity of 1-NP might rely on 1-NP-caused DNA damage and its combined effects on the suppression of DNA repair and the enhancement of oxidative stress and metabolic enzyme activity.