中文摘要：

观察小鼠全身γ射线辐照不同剂量、照射后不同时间,外周血细胞DNA损伤修复相关蛋白基因表达变化,筛选具有指示生物受照剂量潜力的指标。BALB/c小鼠,以0.8和1.6 Gy/min两种剂量率,分别进行0、2、4、6和8 Gy不同剂量照射。照射后4、8、12、24和48 h眼眶取血,AxyPrep试剂盒抽提全血细胞总mRNA,实时定量聚合酶链反应（Real-time quantitative polymerase chain reaction,RT-PCR）方法分析DNA损伤修复相关蛋白基因ATM（Ataxia telangiectasia mutated）、CDKN1A（Cyclin-dependent kinase inhibitor 1A）、DDB2（Damage-specific DNA-binding protein 2）和GADD45A（Growth arrest and DNA damage-inducible,alpha）转录水平。GraphPad Prism 5.0 software package（GraphPad Software,USA）进行数据统计分析。结果表明,与未照射对照组比,在2—8 Gy剂量范围,0.8 Gy/min剂量率照射条件下,照射后所有观察时间点,基因ATM、CDKN1A、DDB2和GADD45A表达均发生显著性变化,变化程度与受照剂量和照射后时间存在效应关系。相同照射剂量条件下剂量率增高,基因表达变化的幅度更明显。依据上述基因随照射后不同时间表达改变的信息,有可能在一定辐照剂量范围内,用DNA损伤修复蛋白基因表达指标估计生物体受照剂量大小。

英文摘要：

In this paper the expression changes of genes involved in DNA repair induced by radiation at different doses and post-irradaition time points has been investigated and the possibility of combining some genes as bio-markers for bio-dosimeter has been evaluated.The whole body of experimental mice was irradiated with 0,2,4,6 and 8 Gy 137Cs γ-rays at 0.80 Gy/min and 1.60 Gy/min,respectively.Peripheral blood was collected at immediate,4,8,12,24 and 48 h after irradiation and RNA was extracted by AxyPrep Kit.The mRNA transcriptional expression levels of ATM,CDKN1A,DDB2 and GADD45A were detected by real-time quantitative polymerase chain reaction（RT-PCR）.Expression changes of mRNA were compared with that of unirradiated control group at the dose rate of 0.8 Gy/min.A series of dose-and time-response of the changes were figured out.A heavy change in magnitude of genes transcrip-tion induced by irradiation at higher exposure dose rate could be found.The information from gene expression analy-sis as a greatly potential biomarkers may be used to indicate exposure doses at different post irradiation time points in a certain dose range.