The Effect Of X-ray On Immune Response Of The Peritoneal Macrophage Of Mice

The organic immunity can be generally categorized into adaptive immunityand innate immunity. Organism recognizes determinants of microbe by theelements in the system of innate immunity when humoral and cellular immunitystart in the early stage, then the microbe innate immunity is regulated and theadaptive immunity is built up. The process of immune response depends on theinteractions of immune cells of the immune system, including direct contacts ofimmune cells and cytokine or mediums releasing. Immune cell membranemolecules including antigens, receptors and other molecules on the cell surfaceare the bases of recognition between immune cells or between cells and mediums. Toll receptor and its signal pathway on the macrophage membrane playimportant role in anti-tumor and anti-inflammatory effect. At present Toll signalpathway and its component has been basically identified. That is: the membranereceptors of CD14,TLR4/TLRs→adaptor protein MyD88 in cytoplasm→nucleartranscription factor κB→effector cytokine IL-12,IL-18. This study observe thechanges of every components in the Toll signal pathway, and discuss the immuneresponse mechanism of macrophage of mice after whole body irradiation (WBI).This experimental results supply theoretical bases for clinical irradiative andanti-inflammatory therapy. Objective: To observe the effect and mechanism of X-ray irradiation onToll-mediated signaling pathway of peritoneal macrophages of mice.Materials and methods: Collecting peritoneal macrophages of mice whichhave been radiated on the whole body with high doses radiation (HDR) and lowdoses radiation (LDR) by the X-ray machine. Culturing the collections with theculture medium of RPMI1640 in 37℃, 5%CO2 culture box. Observing thetime-course changes and dose-effect changes of CD14, TLR4 and MyD88 byFlow cytometry (FCM). The change of nuclear factor κB was detected byanalytical method of gal electrophoresis. ELISA was used to detect thetime-course changes and dose-effect changes of IL-12,IL-18 in Toll signalpathway in the peritoneal macrophages of mice.Results: 1,The expression of CD14 and TLR4 in peritoneal macrophages ofmice after whole body irradiation (WBI): (1) Time-course changes: both of thembegin to increase at 4 h,to reach the peak between 8h and 16h,then dropgradually to sham-irradiation level at 48h;(2) Dose-effect changes: theexpressions are up-regulated. The statistic significances are achieved from0.075Gy, and the peak emerges between 1.0Gy and 2.0Gy. Then it drops between4.0Gy and 6.0Gy. The changes' trend are same for both receptors. 2,Theexpressions of MyD88 in peritoneal macrophages of mice after WBI: (1)Time-course changes: both HDR and LDR increase the expressions of MyD88.The peak emerges between 16h and 24h,and drops to sham-irradiation level at48h;(2)Dose-effect changes:the expressions are up-regulated. The peak emergesat dose point of 2.0Gy,then drops between 4.0Gy and 6.0Gy. 3,The effect ofX-ray irradiation on NF-κB binding activities: (1) Time-course changes afterHDR and LDR: In peritoneal macrophages of mice both p65/p50,p50/p50 andratio of them begin to increase at 4h , to reach the peak at 8h after LDR;Theheterodimer,homodimer and ratio of them begin to increase at 8h,the ratio reachtwo times more than sham group at 72h after HDR. (2) Dose-effect changes: thebinding activities of heterodimer of NF-κB increase with dose of irradiation thanthe control group, but homodimer of that has droping decline. 4,The secretion ofIL-12,IL-18 in peritoneal macrophages of mice after WBI. The results of the twocytokine has coincident trend. (1) Time-course changes: The secretion of IL-12,IL-18 increase with time after HDR and LDR. Generally the level of HDR groupmore higher than LDR group. (2) Dose-effect changes: The secretion of the twocytokine increase with rising of doses. The statistic significances are achievedfrom 0.075Gy, the peak level emerges between 1.0Gy and 2.0Gy, then dropsbetween 4.0Gy and 6.0Gy.Conclusions: 1,The expressions of the membrane receptors (CD14,TLR4),the adaptor protein MyD88 in cytoplasm,nuclear NF-κB,effector cytokine(IL-12,IL-18) significantly increase after WBI of X-ray. 2,All kind of everyresults has coincident trend, the expression level of HDR group generally morehigher than that of LDR. It is show that the effect of X-ray on immune response ofmacrophages of mice is through the Toll signal pathway: CD14,TLR4/TLRs→MyD88 →NF-κB →IL-12,IL-18. 3,This study not only analyzed themechanism of the immune effect of X-ray on peritoneal macrophage of mice, butalso supply theoretical guide for clinical irradiation treatment and anti-tumor,anti-inflammatory therapy.