摘要目的 采用实时定量PCR技术,检测人外周血淋巴细胞DNA损伤反应相关基因表达对X射线全身照射的反应,为探索新型辐射生物标志物奠定基础.方法 以吸收剂量为0、1、2、3、4、5 Gy X射线照射正常人外周血,在照射后4和24 h,应用实时定量PCR法,对淋巴细胞细胞周期素依赖性蛋白激酶抑制物蛋白1a(Cdknla)、生长阻滞和DNA损伤基因45a(Gadd45α)基因的表达变化进行检测.应用胞质分裂阻滞微核法(CB微核法),检测淋巴细胞微核率变化.结果 Cdknla基因在人外周血淋巴细胞受到1～5 Gy照射后4和24 h,其相对表达量均较对照组显著性升高,至4 Gy达到峰值,5 Gy后不再继续增加.Cdknla基因表达与照射剂量呈线性相关(r=0.946、0.975,P<0.05).Gadd45ct基因在1～5 Gy照后4和24 h,其相对表达量均呈剂量依赖性升高,且照射后4 h的表达高于24 h(r=0.936、0.797,P<0.05).CB微核法中,在1～5 Gy X射线照射后4和24 h,各剂量组淋巴细胞微核率均显著增多,呈现良好的线性关系(r=0.990、0.984,P<0.05).结论 辐射使Cdknla基因和Gadd45α基因表达上调,表现出较好的剂量线性关系,有可能成为研制新型辐射生物剂量计的候选基因.

abstractsObjective To detect the expression of DNA damage response genes induced by radiation in human peripheral blood lymphocyte,and to explore the new biomarkers of radiation.Methods The human peripheral blood cells were irradiated to X-rays at different doses of 0,1,2,3,4,and 5 Gy.The quantitative real.time qPCR wag used to detect the expressions of cyclin-dependent kinase inhibitor l a gene(Cdknl a)and growth arrest and DNA damage inducible gene(Gadd45a)in lymphoeytes at 4 and 24 h post-irradiation,respectively.The method of CB mieronucleus was used to determine the change of micronucleus ratio.Results The expression of Cdknl a in peripheral blood lymphocytes wag increased significantly at 4 and 24 h post-irradiation to 0-5 Gy.reached the peak at 4 Gy and began to decrease at 5 Gy,which showed a dose-dependent manner(r=0.946,0.975,P<0.05).Similarly,the expression of Gadd45α in human peripheral blood lymphocytes was also increased significantly at 4 and 24 h post-irradiation to 0-5 Gy in a dose-dependent manner,while the expression of Gadd45a at 4 h wag higher than that at 24 h(r=0.936,0.797,P<0.05).The ratio of micronuclei wag increased significantly at 4 and 24 h post-irradiation to 0-5 Gy(r=0.990,0.984,P<0.05).Conciusions Cdknl a and Gadd45α expression could be increaged significandy at 4 and 24 h post-irradiation to 0-5 Gy,showing a good linear relationship.which might be candidate for radiation biological dosimeter.