不同粒径纳米氧化铈对X线辐照小鼠外周血免疫细胞数量及构成的影响

Effects of different sizes of cerium oxide nanoparticles on the number and constitute of immune cells in peripheral blood of the mice after X-ray irradiation

目的 观察不同粒径的纳米氧化铈对X线辐照小鼠外周血免疫细胞数量及构成的影响.方法 小鼠按体质量分层后随机分为4组,具体方法：称量每只小鼠的体质量,按体质量从高到低依次分为6组,每组4只,然后从每组中随机各取1只,分别形成对照组、模型组、5 nm氧化铈组和25 nm氧化铈组,每组6只.模型组和纳米氧化铈组小鼠经X线一次性全身照射,照射剂量3 Gy;纳米氧化铈组小鼠于照射前4天,1次/d分别腹腔注射10 μg/kg体质量的5 nm氧化铈或25 nm氧化铈,照射后每隔2 d注射1次纳米氧化铈;对照组和模型组小鼠腹腔注射0.9 % NaCl溶液.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,采用流式细胞术分析淋巴细胞亚群构成.结果 与对照组相比,模型组外周血白细胞总数、中性粒细胞数及百分比、单核细胞数及百分比、淋巴细胞数、总T细胞数及百分比、CD4＋和CD8＋T淋巴细胞数及百分比均降低,差异均有统计学意义（均P＜0.05）;淋巴细胞数、B细胞和NK细胞百分比、CD4/CD8比值均升高,差异均有统计学意义（均P＜0.05）.与模型组相比,5 nm氧化铈组除总T细胞百分比、CD4＋和CD8＋T细胞百分比差异无统计学意义（均P＞0.05）外,其余上述指标均有改善,差异均有统计学意义（均P＜0.05）.与对照组相比,5 nm氧化铈组白细胞总数及淋巴细胞数均降低,差异均有统计学意义（均P＜0.05）,其余指标与对照组比较,差异均无统计学意义（均P＞0.05）.与对照组相比,25 nm氧化铈组白细胞总数、淋巴细胞数、总T细胞数及百分比、CD4＋和CD8＋T细胞数及百分比均降低,NK细胞百分比、CD4/CD8比值均升高,差异均有统计学意义（均P＜0.05）;25 nm氧化铈组淋巴细胞数和CD8＋T细胞数均低于5 nm氧化铈组,差异均有统计学意义（均P＜0.05）.结论 不同粒径纳米氧化铈对X线辐照小鼠免疫细胞的影响不同,5 nm氧化铈优于25 nm氧化铈.

Objective To investigate the effects of cerium oxide nanoparticles of different sizes on the number and constructions of immune cells in peripheral blood of mice after X-ray irradiation. Methods Mice were randomly divided into 4 groups according to body weight layer and the weight of each mouse was weighed. All mice were divided into 6 groups according to weight from high to low, and there were 4 mice in each group. Then 1 mouse was randomly taken from each group to form the control group. Model group, 5 nm and 25 nm cerium oxide nanoparticles groups were formed in turn. There were 6 mice in each group. The mice in model group and cerium oxide nanoparticles administration groups were irradiated once with 3 Gy of X-rays. The mice in cerium oxide nanoparticles groups began to be intraperitoneally administrated once a day with 10 μg 5 nm or 25 nm cerium oxide nanoparticles per kilogram body weight on the 4th day before irradiation and once every other 2 days after irradiation. The mice in the control group and model group were intraperitoneally administrated with 0.9 % saline. The mice were killed on the 10th days after irradiation. White cells count （WBC） and classification in peripheral blood were detected by using automatic globulimeter, and lymphocyte subsets were analyzed by using flow cytometry. Results Compared with the control group, the number of WBC, neutrophil granulocytes, monocytes, lymphocytes, total T lymphocytes, CD4＋and CD8＋T lymphocytes and the percentages in the model group were decreased （all P〈0.05）, and percentages of the lymphocytes, B cells and NK cells and ratio of CD4 to CD8 were increased in model group （all P〈 0.05）. Compared with the model group, the above parameters except percentages of T lymphocytes, CD4＋and CD8＋T lymphocytes were improved in mice of 5 nm cerium oxide nanoparticle group （all P 〈0.05）. Compared with the control group, the number of WBC and lymphocytes were decreased in the 5 nm cerium oxide nanoparticle group （P〈0.05）, and there were no significances in other parameters compared with the control group （all P 〉0.05）. Compared with the control group, the number of WBC and lymphocytes, the number and percentages of T lymphocytes, CD4＋and CD8＋T lymphocytes and the percentages were decreased （all P〈 0.05）, and percentage of NK cells and ratio of CD4 to CD8 were significantly increased in 25 nm cerium oxide nanoparticles group （all P〈 0.05）. The number of lymphocytes and CD8＋T lymphocytes in 25 nm cerium oxide nanoparticles group was lower than that in 5 nm cerium oxide nanoparticles group （all P 〈 0.05）. Conclusions The effects of cerium oxide nanoparticles of different sizes on the immune cells of mice after X-ray irradiation are different, and 5 nm cerium oxide nanoparticle is superior to 25 nm cerium oxide nanoparticle.