2Gy γ射线照射对小鼠调节性T细胞和Th17细胞及其免疫平衡的影响

Effects of 2 Gy v-irradiation on the number of regulatory T cells and Thl7 cells and immunebalance in mice

目的观察2Gy1射线照射对小鼠Treg／Thl7免疫平衡的影响。方法50只C57BL／6雄性小鼠随机数字表法分为对照组和照射组，照射组小鼠接受2Gy吖射线-次性全身照射（剂量率为164．94Gy／min），对照组行假照射。于照射后1…3714和28d检测外周血象的变化；流式细胞仪分析外周血、胸腺及脾脏调节性T细胞（Treg细胞）和脾脏Thl7细胞数量的改变。结果受照后小鼠外周血白细胞总数和淋巴细胞数降低（t=8．89～33．54，P〈0．05）。小鼠外周血Treg略有升高；胸腺Treg在照后1、3d显著高于对照组（t=-6．45和-10．59，P〈0．05），至28d明显低于对照组（t=5．34，P〈0．05）；脾脏Treg在照后1—14d显著高于对照组（t=-6．82--3．89，P〈0．05）。脾脏Thl7细胞于照后1d出现显著增高，3d达到最大值（t=-2．42，P〈0．05），较脾脏内Treg增长更为明显。Treg／Thl7比值在照后1—14d降低，差异有统计学意义（t=4．02～8．04，P〈0．05），导致Treg／Thl7平衡模式向Thl7方向明显偏移。结论Treg／Thl7免疫平衡失调在辐射所致免疫功能损伤中可能扮演重要角色。

Objective To observe the effects of 2 Gy y-ray irradiation on regulatory T cells （Tregs） and ThI7 ceils and immune balance of mice. Methods A total of fifty C57BL/6 male mice were randomly divided into two groups, the irradiated group exposed to 2 Gy of whole body y-ray irradiation, and the control group sham-irradiated. At 1, 3, 7, 14 and 28 d after radiation, changes of peripheral haemogram were detected respectively and Tregs in peripheral blood, thymus and spleen and Thl7 ceils in spleen were analyzed by flow cytometry. Results Compared with control group, the number of peripheral blood white cells （ WBC ） and lymphocyte in irradiated group reduced significantly post-irradiation （ t = 8.89 - 33.54, P 〈 O. 05） , while the cell number of peripheral CD4 ＋ CD25 ＋ Tregs post-irradiation rose but not significantly. Thymic Treg ceils increased 1 and 3 d post-irradiation（t = -6.45, - 10. 59, P 〈 0.05） , but reduced 28 d post-irradiation （ t = 5.34, P 〈 0.05 ）. Splenic Treg cells ascended obviously from 1 to 14 d post-irradiation （t = - 6. 82 - 3.89, P 〈 O. 05 ）. After irradiation splenic Thl7 ceils increased at 1 d, and reached the maximal level at 3 d （ t = - 2. 42, P 〈 0.05 ）, more obviously than splenic Treg cells. The.reduction of Treg/Thl7 ratio from 1 to 14 d post-irradiation disturbed Treg/Thl7 balance thd made it drift to the direction of Th17 （ t = 4. 02 - 8.04, P 〈 0. 05 ）. Conclusions Treg/Thl7 imbalance plays an important role in immune injury induced by irradiation.