ABSTRACT
<p><b>OBJECTIVE</b>To explore the genotoxic effects of oral-exposed TiO2 nanoparticles on bone marrow cells in young rats.</p><p><b>METHODS</b>Twenty-eight SD male young rats (4 weeks old) were randomly divided into 4 groups, which were exposed to TiO2 nanoparticles ((75 ± 15) nm, anatase) through intragastric administration at 0, 10, 50 and 200 mg/kg body weight (bw) every day for 30 days. The bone marrow cells were collected for micronuclei and γ-H2AX immunofluorescence analysis.</p><p><b>RESULTS</b>The percentage of γ-H2AX foci-positive cells (37.4 ± 10.0)% in the 50 mg/kg bw dose group were significantly higher than that in the control group (19.8 ± 3.1)% (t value was -17.59, P < 0.01). No significantly difference was found in polychromatic erythrocyte/normochromatic erythrocyte (PCE/NCE) ratio and PCE micronucleus rate between three experimental groups and control group.</p><p><b>CONCLUSION</b>TiO2 nanoparticles can increase the frequency of DNA double-strand breaks in bone marrow cells, but has no effect on micronucleus of bone marrow cells in young rats.</p>