纳米氧化铈对X射线照射小鼠外周血免疫细胞分布及脾脏T淋巴细胞增殖能力的影响

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

目的观察纳米氧化铈对X射线引起的小鼠免疫损伤是否具有保护作用。方法小鼠按体重分层分为7组：对照组、模型组、模型＋不同剂量纳米氧化铈组（模型＋10ng组、模型＋100ng组、模型＋1μg组、模型＋10μg组、模型＋100μg组），每组各6只。模型组和纳米氧化铈组小鼠经X射线1次性全身照射，照射剂量4Gy，纳米氧化铈组小鼠于照射前4d开始，分别腹腔注射10、100ng／kg，1、10和100μg／kg体重的纳米氧化铈，每周2次，照射后第10天处死小鼠。采用全自动血细胞计数仪进行外周血白细胞计数及分类；采用流式细胞术检测T、B、NK、CD4＋、CD8＋T淋巴细胞的百分比，计算CD4／CD8比值；采用四甲基偶氮唑盐（MTT）法检测脾脏T淋巴细胞增殖能力。结果与对照组相比，经X射线照射小鼠外周血的白细胞总数和NK细胞绝对值，中性粒细胞、单核细胞、总淋巴细胞、T淋巴细胞、CD4＋和CD8＋T淋巴细胞的绝对值及百分比，脾脏T淋巴细胞增殖能力均降低（t=2．26～3．18，P〈0．05）；B淋巴细胞百分比和CD4／CD8比值升高（t=2．45、3．18，P〈0．05）。X射线照射小鼠腹腔注射不同剂量的纳米氧化铈对上述免疫学指标有改善作用，其中以10和100μg纳米氧化铈组改善效果明显，而10μg组改善作用最佳。结论纳米氧化铈能够提高X射线照射小鼠的免疫功能。

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 ceils, and T lymphocyte proliferation of spleen were respectively analyzed by hymoeytometer, flow cytometly and MTT assay. The ratios of CD4 ＋ to CD8 ＋ cells were ealculated. Results Compared with control group, the numbers of leukocytes and NK cells, numbers and percentages of neutrophil granuloeytes, 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 nanoparticlcs, 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.