Changes Of Treg/Th17Immunological Balance Induced By γ-irradiation And Its Relative Mechanisms

Objective:To observe the effects of γ-ray acute irradiation on the Treg/Thl7balance and PI3k/Akt pathway of mice, expecting to provide experimental evidence for further study of the molecular mechanisms of immune injury induced by irradiation.Methods:1) Male C57BL/6mice were randomly divided into the irradiated group and the control group, the irradiated group was exposed to2Gy and6Gy whole body60Co y-irradiation, and the control group was sham-irradiated. At1,3,7,14and28d after radiation, changes of spleen and thymus coefficient and peripheral haemogram were detected respectively, while, changes of Tregs in the peripheral blood, thymus and spleen and Th17in the spleen were analyzed by flow cytometry.2) Sorted CD4+CD25-T cells and CD4+CD25+Tregs were divided into the irradiated and control groups respectively. The irradiation group exposed to2Gy and4Gy60Co y-irradiation, and the control group was sham-irradiated. After radiation, the apoptosis of CD4+CD25-T cell and CD4+CD25+Tregs and their phosphorylation level of Akt in PI3K/Akt pathway were analyzed by flow cytometry.Results:1) After y-ray irradiation, Treg and Th17in mice increased significantly, and the ratio of Treg/Th17reduced significantly (-P<0.05).2) Apoptotic rate of CD4+CD25-T cells and CD4+CD25+Tregs both increased significantly, and the apoptotic rate of the former was significantly higer than the latter post irradiation.3) The phosphorylation level of Akt in CD4+CD25+Tregs were significantly higher than those of CD4+CD25-T cell (P<0.05) post y-ray irradiation.Conclusions:1) Whole body γ-irradiation can induce the balance of Treg/Th17of mice drift to Th17cells, Treg/Th17imbalance may play an important role in immune injury induced by irradiation.2) The phosphorylation level of Akt is higher in CD4+CD25+Tregs, which results in a lower apoptotic rate of CD4+CD25+Tregs, suggesting that Tregs possess high radiation resistance. Figure20, table3, reference99.