摘要目的 探讨人外周血经不同剂量60co γ射线照射后淋巴细胞损伤情况,以及与磷酸化的H2AX、ATM表达的关系.方法 永生化淋巴细胞及人新鲜外周血淋巴细胞经0～8 Gy 60 Coγ射线照射后0.5 h,分别采用Western blot和流式细胞术检测磷酸化ATM和γ-H2AX的表达情况,并通过CB微核法检测受照射后人外周血淋巴细胞微核验证细胞损伤程度.结果 流式细胞检测发现人外周血淋巴细胞照射后0.5 h,γ-H2AX表达的剂量效应关系呈线性平方模式,其拟合曲线为:Y=3.96+11.29D-0.45D2,而相同方法检测磷酸化ATM蛋白的表达未见明显变化.Western blot检测结果表明,照射后0.5 h,各受照射组磷酸化ATM表达在0.1～8 Gy范围内具有呈剂量依赖性增高的趋势.人外周血淋巴细胞微核结果显示,γ射线照射后DNA损伤情况明显加重,随吸收剂量的增加,微核细胞率明显增多.结论 60Co γ射线可诱导DNA双链断裂,随着吸收剂量的增加,微核率明显增加,磷酸化的H2AX、ATM表达水平亦明显增高,本研究为辐射损伤及辐射事故生物剂量估算领域的研究提供了理论依据.

abstractsObjective To investigate 60Co γ-ray induced damage in lymphocytes and the relationship between doses of 60Co γ-ray irradiation and the levels of phosphorylated H2AX and ATM.Methods Cells were irradiated with 60Co γ-rays in the range of 0-8 Gy.The levels of phosphorylated H2AX and ATM were detected by Western blot and FACScan,respectively.The micronucleus(MN)was analyzed by CB method to evaluate DNA damage.Results FACScan results showed the dose-effect relationship of γ-H2AX expression were linear.square at 0.5 h post-irradiation to different doses,and the fitting curve was shown as Y=3.96+11.29D-0.45D2.The level of phosphorylated ATM(p-ATM)was not changed significantly by using the same method.Western blot showed that p-ATM protein expression was significandy increased after irradiation compared with sham.irradiated group.The MN assay which represented DNA damage was sensitive to different doses.Conclusions γ-ray irradiation could induce the phosphorylation of H2AX and ATM,which may play an important role in indicating DNA damage.Both of H2AX and ATM have the potential as sensitive biomarker and biodosimeter for radiation damage.