Protective effect of cerium oxide nanoparticles on mice induced by γ-rays

Objective: To investigate the protective effect of cerium oxide (CeO₂) nanoparticles on mice induced by γ-rays. Methods: 140 BALB/c mice were randomly divided into normal control group, irradiation control group, positive control group treated with amifostine, low dose group treated with 100 mg/kg of CeO₂ nanoparticles, medium dose group treated with 300 mg/kg of CeO₂ nanoparticles and high dose treated with 900 mg/kg of CeO₂ nanoparticles. Mice were induced by 3.5 Gy of ⁶⁰Co and dose rate was 1 Gy/min. Mice were sacrificed three days and eight days after irradiation, spleen and thymus index, micronucleus rate of bone marrow polychromatic erythrocytes were examined as well as blood serum SOD and actin cytoskeleton in thymus lymphocytoplasm eight days after irradiation. Results: Three days after the irradiation, compared with the irradiation control group, the thymus index significantly increased in medium dose and high dose group (P < 0.05 or P < 0.01), it's better than that of positive control group. The spleen index increased with the increase of dose of CeO₂ nanoparticles, but the difference was not statistically significant. Micronucleus rate of bone marrow polychromatic erythrocytes decreased in each CeO₂ nanoparticles administration group, and the significant difference was found in low dose group (P < 0.05), it's better than that of positive control group. Eight days after the irradiation, compared with the irradiation control group, Micronucleus rate of bone marrow polychromatic erythrocytes in CeO₂ nanoparticles administration groups decreased. Compared with the irradiation control group, in CeO₂ nanoparticles medium dose group, there was a tendency of increase of blood serum SOD activity, but the difference was not statistically significant, and actin cytoskeleton was more clear and complete. Conclusion: CeO₂ nanoparticles have a certain anti-radiation activity, it may be related to the immune capacity improvement and the hematopoietic tissues protection from the damage induced by radiation. (authors)