γ射线诱导的肝癌细胞DNA双链断裂

摘要

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SMMCrn-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rn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rn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 mechanismrn of radiobiological effects, the inverse pulsed-field gel electrophoresis has been applied to separate DNA from hepatoma SMMC-7721 cells cultured fornr 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 rn(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 reparnired 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. Itrn is elucidated that DSBs induced by γ-ray are easy to be rejoined and the remaining DSBs are the cause of cell death.