γ射线诱导的肝癌细胞DNA双链断裂  

DNA double-strand breaks induced by γ-ray

作　　者：周光明[1] 李文建[1] 王菊芳[1] 何静[1] 高清祥[2] 陈炜[2] 卫增泉 

机构地区：[1]中国科学院近代物理研究所,兰州730000 [2]兰州大学,兰州730000

出　　处：《核技术》2000年第11期776-779,共4页Nuclear Techniques

基　　金："攀登计划B"项目;中国科学院兰州分院基金资助

摘　　要：为了揭示辐射生物学效应的机理，用倒转脉冲场凝胶电泳（ＰＩＧＥ）研究了γ射线辐照肝癌ＳＭＭＣ—７７２１细胞诱导的ＤＮＡ双链断裂（ＤＳＢ）及其修复２４、４８ｈ后的产额和片段的分布情况。结果表明：修复０ｈ和２４ｈ的样品，ＤＮＡ片段释放百分比（ＰＲ）随着剂量的增加而增加；诱导的ＤＳＢ片段主要是 １Ｍｂｐ— ２Ｍｂｐ的大片段； ＤＳＢ产额分别为 ０．３８ＤＳＢｓ／１００Ｍｂｐ· Ｇｙ和０．０６ＤＳＢｓ／１００Ｍｂｐ·Ｇｙ，即２４ｈ内，约８４％的ＤＳＢ发生了重接；修复４８ｈ后残余的ＤＳＢ片段与剂量无关，且与对照细胞的ＤＳＢ片段含量相近。可见，γ射线诱导的ＤＳＢ容易发生修复；未修复的ＤＳＢ将导致细胞的增殖死亡。In order to study the mechanism of radiobiological effects, the inverse pulsed-field gel electrophoresis has been applied to separate DNA from hepatoma SMMC-7721 cells cultured for various hours after exposed to γ -ray. Results showed that, in the samples repaired for 0 and 24 hours, the percentages of DNA released from plug (PR) increased with dose. The fragments were mainly 1-2Mbp and the yields of DSB in the two kinds of samples were 0.38DSBs/100Mbp· Gy and 0.06DSBs/100Mbp·Gy, respectively. Thus 84% DSBs were rejoined. In the samples repaired for 48 hours, the remaining DSB fragments induced with different doses were similar to the control and seem to have nothing to do with dose. It is elucidated that DSBs induced by γ -ray are easy to be rejoined and the remaining DSBs are the cause of cell death.

关 键 词：Γ射线 DNA双链断裂 电泳 肝癌细胞 

分 类 号：Q345.2[生物学—遗传学] R734.2[医药卫生—肿瘤]