Effects of cerium oxide nanoparticles on mouse immune system injury induced by γ-ray irradiation

Abstract

Objective To study the effects of cerium oxide nanoparticle on immune system injury induced by γ-ray irradiation. Methods BALB/c mice were randomly divided into 6 groups (5 mice each group) including normal control, irradiation group, positive control group, 100 mg/kg CeO2 nanoparticle group, 300 mg/kg CeO2 nanoparticle group and 900 mg/kg CeO2 nanoparticle group. All mice were irradiated in whole body by 3.5 Gy 60Co γ-rays except the normal control group. They were treated with drugs by intragastrical administration from 2 weeks before exposure till death. The apoptosis rate of thymus lymphocytes and the positive rate of IL-2 and IFN-γ in peripheral blood were examined by flow cytometry. The activity of natural killer cells was examined by MTT. Results Compared with the irradiation control group, at 3 d after exposure, the death rates of thymus lymphocytes of the CeO2 nanoparticle groups were decreased, especially in the medium dose group (F=4.50, P 0.05). The activity of natural killer cells of the CeO2 nanoparticle groups and positive control group were higher than that of control (t=3.40, 5.40, 3.40, 5.20, P<0.05). Conclusions CeO2 nanoparticle can reduce the death rate and the apoptosis rate of the thymus lymphocytes in the γ-ray irradiated mice by increasing the expressions of IL-2 and IFN-γ, the activity of natural killer cells and the mice immunity. CeO2 nanoparticles may have protective effects against radiation injury. Key words: Cerium oxide nanoparticles; Apoptosis; Cytokine; Activity of natural killer cells; Immune function