Effects of 2 Gy γ-irradiation on the number of regulatory T cells and Thl7 cells and immune balance in mice / 中华放射医学与防护杂志

ABSTRACT

Objective To observe the effects of 2 Gy γ-ray irradiation on regulatory T cells (Tregs) and Th17 cells 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 γ-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 Th17 cells 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 ＜ 0.05),while the cell number of peripheral CD4 + CD25 + Tregs post-irradiation rose but not significantly.Thymic Treg cells 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 ＜ 0.05).After irradiation splenic Th17 cells 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/Th17 ratio from 1 to 14 d post-irradiation disturbed Treg/Th17 balance and made it drift to the direction of Th17 (t =4.02-8.04,P ＜ 0.05).Conclusions Treg/Th17 imbalance plays an important role in immune injury induced by irradiation.