Effects Of Low Dose Irradiation On Immune Cells And Their Functions

Background:The interaction between irradiation and immune system is characterized by complexity and diversity,and its biological effects depend on irradiation dose/dose rate,irradiation mode and different types of immune cells.The application of irradiation in the medical field mainly focuses on the radiotherapy of tumors and the inactivation of lymphocytes in blood products,and is not in the scope of low dose.In recent years,through the establishment of various animal whole-body irradiation models,low dose irradiation has been used for protective research.In transfusion-related immune regulation,there are few reports on the effect of low-dose irradiation on peripheral blood immune cells.It is possible to find a new model for the treatment of immune diseases by exploring whether different types of immune cells have different tolerance to low-dose irradiation.Objective:In vitro experiments,the effects of low dose irradiation on human peripheral blood immune cells and their functions were explored;In vivo experiments,the effects of low dose irradiation on the immune cells and immune function of experimental rats after the treatment of a small amount of peripheral blood and its transfusion were studied.In order to provide a new idea for the treatment of immune diseases.Methods:In vitro experiments,peripheral blood samples of healthy adult male volunteers were collected,and human peripheral blood lymphocytes were isolated and extracted.The total dose of 300 m Gy was used to irradiate 6 times(50 m Gy/time),3times(100 m Gy/time),and 2 times(150 m Gy/time)respectively.The interval between each irradiation was 24 hours.The apoptosis,proliferative activity,cycle,and cytokine secretion of lymphocyte subsets were detected 24 hours after the last irradiation of each dose.In vivo experiment,a rat model of low dose irradiation treatment of peripheral blood was constructed.Male SD wild-type rats were selected.One side of the femoral artery of the rats was passively separated,and arterial blood(10%of the circulating blood volume)was extracted into a sodium citrate anticoagulant tube,which was irradiated at 150 m Gy.After irradiation,it was infused back through the femoral vein.After 24 hours,the femoral artery on the other side of the rat was passively separated,and arterial blood(10%of the circulating blood volume)was extracted into a sodium citrate anticoagulant tube,and irradiated at 150 m Gy.After irradiation,it was infused back through the femoral vein.At the 1st,3rd and 7th days after the last irradiation,the routine test of rat peripheral blood,the proportion of rat peripheral blood lymphocyte subsets(CD3~+T lymphocytes,CD45RA B lymphocytes,CD161a NK cells,CD4~+T lymphocytes,CD8~+T lymphocytes,CD4~+T/CD8~+T,CD45RA B/CD3~+T),and the content of rat serum cytokines(IFN-γ、IL-12、IL-4、IL-10),the content of serum immunoglobulin in rats(Ig A、Ig G、Ig M).Results:1.Compared with the sham irradiation group,the apoptosis rate of lymphocyte subsets after irradiation treatment increased significantly.In the 50 m Gy/time irradiation group,CD3~-CD56~+NK>CD3~+T>CD3~-CD19~+B cells;in the 100 m Gy,150 m Gy/time irradiation group,CD3~-CD56~+NK>CD3~-CD19~+B>CD3~+T cells;2.After 50 m Gy,100 m Gy and 150 m Gy/time of X-ray irradiation,lymphocyte proliferation activity was inhibited;3.After 24 hours of PHA stimulation of lymphocytes,50 m Gy,100 m Gy and 150m Gy/time of X-ray irradiation treatment blocked lymphocytes in G0/G1 phase;4.In the 100 m Gy and 150 m Gy/exposure dose groups,IL-1βDecreased secretion,TNF in 100 m Gy/irradiation dose group-αDecreased secretion;5.At 1,3 and 7 days after arterial transfusion treated with low-dose irradiation,there was no significant numerical change in peripheral blood routine of rats in the experimental group compared with the sham irradiation group;6.On the 1st,3rd and 7th day after the arterial blood transfusion of low-dose irradiation treatment,compared with the sham irradiation group,the positive rates of CD3~+T,CD8~+T,CD3~-CD161a NK cells in the experimental group were different but not statistically significant;The positive rates of CD3~-CDRA B and CD4~+T cells changed significantly;The ratio of CD4~+/CD8~+T in the experimental group decreased significantly;The ratio of CD3~-CD45RA B cells to CD3~+T cells increased significantly in the experimental group;7.On the 1st,3rd and 7th days after the femoral artery blood was transfused through the femoral vein after low dose irradiation treatment,compared with the sham irradiation group,the concentration of serum cytokine IFN-γdecreased on the 1st day,the concentration of serum cytokine IL-12 and IL-4 decreased on the 1st,3rd and 7th days respectively,and the concentration of serum cytokine IL-10 increased on the 1st,3rd and 7th days respectively;8.The serum Ig A、Ig M and Ig G concentrations were increased in the low dose irradiated femoral artery blood at 1,3 and 7 days after transfusion through the femoral vein compared with the sham irradiated group.Conclusion:The same dose and different low-dose irradiation induced apoptosis treatment mode showed different irradiation sensitivities to human peripheral blood lymphocyte subsets,which inhibited the proliferative activity and cytokine secretion ability of some lymphocytes and blocked lymphocytes in the G0/G1 phase.In rats,the ratio of CD4~+/CD8~+T decreased,the ratio of CD3~-CD45Ra B cells to CD3~+T cells increased,the concentration of serum IL-12 and IL-4 decreased,the concentration of serum IL-10 increased,and the concentration of serum Ig A,Ig M and Ig G increased.