Effects of cerium oxide nanoparticles on the distribution of immune cells in peripheral blood and the proliferation of spleen T lymphocyte in X-ray irradiated mice

Abstract

Objective To investigate protective effect of cerium oxide nanoparticles on immune system of X-ray irradiated mice. Methods Mice were randomly divided into 7 groups according to body weight layer: control group, irradiation group, and 5 different doses of cerium oxide nanoparticles administration groups. The mice of irradiation group and cerium oxide nanoparticles administration groups were irradiated once with 4 Gy X-rays. The mice of cerium oxide nanoparticles administration groups began to be intraperitoneally administrated with 10 ng, 100 ng, 1 μg, 10 μg and 100 μg cerium oxide nanoparticles per kilogram body weight twice a week on the fourth day before irradiation and these mice were killed on the tenth day after irradiation. White cells count and classification, percentages of T, B, NK, CD4+ and CD8+ T cells, and T lymphocyte proliferation of spleen were respectively analyzed by hymocytometer, flow cytometry and MTT assay. The ratios of CD4+ to CD8+ cells were calculated. Results Compared with control group, the numbers of leukocytes and NK cells, numbers and percentages of neutrophil granulocytes, monocytes, total lymphocytes, T lymphocytes, CD4+ and CD8+ T lymphocytes, spleen T lymphocytes proliferation were significantly decreased(t=2.26-3.18, P<0.05), and the percentage of B lymphocytes and ratio of CD4 to CD8 were significantly increased in irradiated mice(t=2.45, 3.18, P<0.05). Above immunology parameters were improved in irradiated mice after intraperitoneally administration with different dose of cerium oxide nanoparticles, especially 10 and 100 μg/kg. The radiation protective effect of 10 μg/kg cerium oxide nanoparticles was the best. Conclusions Cerium oxide nanoparticles can improve the immune function in irradiated mice. Key words: Cerium oxide nanoparticles; Irradiation injury; Immune cells; T lymphocytes; Cell proliferation