Abstract: Objective：To make an assessment on the genotoxicity caused by black carbon (BC) and ozonized black carbon (O₃-BC). Methods: In this study, 74 healthy male ICR mice ［weighed (28±1.5) g］ were randomly divided into 7 groups, including one phosphate buffer solution (PBS) control group and six particles exposed groups by intratracheal instillation with either BC or O₃-BC at the doses of 50, 100, 200 μg/mouse, respectively. There were 12 mice in the groups of 200 μg/mouse and 10 mice in others. The mice were sacrificed 24 h after four intratrachealinstillations. The activities of catalase (CAT) in serum and the levels of malondialdehyde (MDA) in lung tissue homogenate were measured. As the DNA damage mark, 8-hydroxyguanosine (8-OHdG) in urine and serum were quantified with ELISA method. Micronucleus test was used for potential genotoxicity of BC and O₃-BC. Hematoxylin and eosin staining was used to stain lung paraffin section. Results: The mice were in good condition during instillation, and the liver coefficient of the test groups was significantly lower than that of the control group (P<0.05). The activities of CAT in serum significantly increased in the 100 μg/mouse and 200 μg/mouse groups after being exposed to these two kinds of particles. The micronucleus rate in allthe BC and O₃-BC exposed groups increased (P<0.05), but there was no statistically significant difference among the groups in the levels of 8-OHdG in serum and urine and MDA in lung tissue homogenate. Inflammatory response was found in the lung tissue under the microscope after exposure to BC and O₃-BC. Conclusion: Intratracheal instillation of BC and O₃-BC induced increasing of oxidative stress and genetic damage in mice. But there was no significant difference b

Key words: Soot, Ozone, Micronucleus tests, Mice