辐射诱导Gadd45基因表达作为生物剂量计的实验室评估

Evaluation of the feasibility with Gadd45 as a radiation biodosimeter

为了考察电离辐照后人外周血中Gadd45基因表达的个体差异,评价Gadd45作为基因表达辐射生物剂量计的实用性,采集了27个健康人外周血进行60Co照射,提取白细胞mRNA,以β-actin作为内对照基因,建立了相对标准曲线法实时定量聚合酶链式反应(Polymerase chain reaction,PCR)方法,并以此方法探索辐照后Gadd45表达的剂量-效应关系。结果表明,0～2.5Gy剂量范围内,Gadd45的mRNA表达水平随照射剂量增加而上调,通过拟合建立了0～2.5Gy剂量范围内,Gadd45/β-actin相对表达量与照射剂量间的剂量-效应直线方程(y=0.216+0.258x,p<0.001,R2=0.650)。发现Gadd45 mRNA表达水平在个体间存在一定差异,应用该剂量-效应直线方程,可以对0～2.5Gy照射剂量范围内的血液照射剂量作相对估算。

To survey the variance of Gadd45 mRNA in different people＇s blood exposured to ionizing radiation, which is necessary in evaluating the feasibility of Gadd45 as a radiation biodosimeter, 27 normal persons＇ peripheral blood was irradiated with ^60Co γ-rays in vitro. And its RNA was isolated from white cell. The relative real-time quantitative PCR by standard curve method was set up using β-actin as internal standards. With this method, Gadd45 mRNA expression change was observed after ionizing radiation. It has been found that in 0-2.5Gy range the rela- tionship between the ratio of Gadd45 mRNA / β-actin and irradiation dose represents certain line correlation. A linear regression equation （y=0.216＋0.258x, p〈0.001, R^2=0.650） has been obtained using statistics regression analysis method which can be used to estimate the biological doses involved in radiation accidents though the variance of the Gadd45 mRNA level among different people is marked.