不同剂量辐射诱导小鼠胸腺Th1-Th2-Th3型细胞相关基因的功能分析

Analysis of Th1-Th2-Th3 related gene expressions in the thymus of mice irradiated with different doses

目的 应用功能分类基因芯片技术,分析高、低剂量全身照射对小鼠胸腺细胞中Th1、Th2及Th3/Tr1各亚型功能相关基因的差异表达,探讨辐射免疫效应的分子机制.方法 健康ICR小鼠按随机数字表法分为低剂量组（0.075 Gy）、高剂量组（2.0 Gy）和假照组,于照射后16 h处死小鼠取胸腺组织,应用细胞因子与炎症反应PCR芯片技术进行Th1-Th2-Th3功能分类芯片分析.结果 低剂量（0.075 Gy）X射线全身照射后小鼠胸腺细胞中有8个基因表达上调,5个基因表达下调;高剂量（2.0 Gy）X射线全身照射后小鼠胸腺细胞中有54个基因表达上调,3个基因表达下调.具体有Th型细胞相关基因、Th2型细胞相关基因、Th3/Tr1型细胞相关基因、Th1/Th2型免疫应答基因以及转录因子相关基因.其中,低剂量辐射诱导胸腺中的Th1型细胞相关基因Stat4和Socs1的表达上调,而对Th2型和Th3/Tr型细胞相关基因IL-4ra、Cebpb、Gata3及Tgfb3下调,最终导致Th1型免疫应答基因Sftpd上调.高剂量辐射均可诱导Th1、Th2和Th3/Tr型细胞相关基因的上调,但Th1型免疫应答基因表达无变化,而Th2型免疫应答相关基因Cd86、IL-18、IL-10以及Irf4上调.结论 低剂量辐射诱导Th1型免疫应答,而高剂量辐射诱导Th2型免疫应答.

Objective To analyze the effect of high and low dose radiation on the expressions of Th1,Th2 and Th3 /Tr1 related-genes in mice thymocytes and investigate the possible underlying molecular mechanism.Methods ICR mice were randomly divided into low-dose group （0.075 Gy）,high-dose group （2.0 Gy） and sham-control group.The mouse thymus tissue was extracted at 16 hours after irradiation and the expressions of Th1-Th2-Th3 related genes were measured by PCR array.Results Eight genes were up-regulated and five genes were down-regulated after low dose radiation （0.075 Gy）;while 54 genes were up-regulated and three genes were down-regulated after high dose （2.0 Gy） radiation.These genes included Th1 cell related genes,Th2 cell related genes,Th3/Tr1 cell related genes,Th1/Th2 immune response genes and transcription factor related genes.Low dose radiation induced up-regulation of Stat4 and Socs1 of genes related to the Th1 cells,and it induced down-regulation of IL-4ra,Cebpb,Gata3 and Tgfb3 associated with Th2 and Th3 cells,which lead to Sftpd genes up-regulation of Th1 immune response eventually.The high dose radiation up-regulated all of Th1,Th2 and Th3/Tr related genes and also enhanced the expressions of Cd86,IL-18,IL-10 and Irf4 genes related to Th2 immune response,but it did not alter the gene expression of Th1 immune response.Conclusions Low-dose radiation induces Th1-type immune response,while high doses radiation triggers Th2 type immune response.