摘要目的 研究纳米氧化铈在γ射线诱导小鼠免疫系统损伤中的影响.方法 BALB/c小鼠120只按随机号法分为健康对照、照射、阳性药物与纳米氧化铈100、300和900 mg/kg组,共6组,每组20只.小鼠经3.5 Gy60Co γ射线一次性全身照射,照射前两周至照射后处死前连续口服灌胃给药.流式细胞术检测胸腺淋巴细胞凋亡率、外周血白细胞介素-2(IL-2)和干扰素-γ(IFN-γ)阳性率,二苯基四氮唑溴盐(MTT)法检测自然杀伤细胞(NK)活性.结果 与照射组相比,受照后3d,纳米氧化铈各剂量组的细胞死亡率均降低,纳米氧化铈300 mg/kg组差异有统计学意义(F=4.50,P ＜0.05),纳米氧化铈300 mg/kg组的IFN-γ表达显著增多(t-2.26,P＜0.05);受照后8d,纳米氧化铈900 mg/kg组的细胞死亡率明显降低(F =4.07,P ＜0.05),纳米氧化铈100 mg/kg组细胞早期凋亡率显著下降(F =3.47,P＜0.05),纳米氧化铈300 mg/kg组IFN-γ表达显著增多(t=2.47,P ＜0.05),各剂量组IL-2表达均呈降低趋势,但差异无统计学意义(P＞0.05);纳米氧化铈各剂量组和阳性药物组的NK细胞活性均显著升高,差异有统计学意义(t=3.40、5.40、3.40、5.20,P＜0.05).结论 纳米氧化铈在一定程度上降低受照小鼠胸腺淋巴细胞凋亡率和死亡率,促进IFN-γ表达量增高,增强NK细胞活性,可提高机体免疫力,对辐射损伤有一定防护作用.

abstractsObjective To study the effects of cerium oxide nanoparticle on immune system injury induced by γ-ray irradiation.Methods BALB/c nice 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-γin 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 positive rate of IFN-γof the medium dose group was also increased (t =2.26,P ＜ 0.05).At 8 d after irradiation,the death rate of the high dose group was declined significantly (F =4.07,P ＜ 0.05),the early apoptosis rate of low dose group were declined sharply (F =3.47,P ＜ 0.05),and the positive rate of IFN-γ of the medium dose group was increased significantly (t =2.47,P ＜ 0.05).The positive rates of IL-2 of CeO2 nanoparticle groups were all decreased,but had no significant differences (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 Ce02 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.