人外周血线粒体DNA4934bp自发缺失及^(60)Coγ射线诱发缺失的剂量效应关系初探

Spontaneous mitochondrial DNA 4934bp deletion in human peripheral blood samples and the preliminary study on dose-response effect of deletion induced by ^(60)Coγ-rays

为探索正常人群外周血样品中线粒体DNA(mtDNA)4934bp缺失的发生比例及电离辐射是否可以诱发该缺失,对109例正常人外周血样品进行分析,确定正常人外周血样品中发生该缺失的比例,将3例缺失阳性正常人外周血样品,使其受到0、2和6Gy60Coγ射线照射,对4934bp缺失发生情况进行研究;经分析发现,41%的正常人外周血样品具有该缺失,聚合酶链反应PCR产物经克隆、测序和核苷酸同源性分析证实该缺失发生在线粒体DNA重链nt8435-nt13368之间。自发缺失发生比例与供者年龄增长相关(p<0.01),与性别无关。使用半定量聚合酶链反应(Polymerase chain reaction,PCR),缺失阳性正常人外周血样品在接受0、2和6Gyγ射线照射后,检测其mtDNA4934bp的缺失情况,发现在照射前后外周血线粒体DNA均有该缺失;以正常人外周血所做的半定量分析发现在照射0、2和6Gy后该缺失水平分别为23、25和27。说明电离辐射诱发人外周血样品缺失水平随剂量增加而增高。

This study is try to investigate the positive ratio of the mitochondrial DNA （mtDNA） 4934bp deletion in normal human population and if this deletion could be induced by ionizing radiation. 109 normal human peripheral blood samples were collected and analyzed for the mtDNA 4934bp spontaneous deletion by PCR. 3 samples of human normal peripheral blood with mtDNA 4934bp spontaneous deletion were exposed to 0, 2 and 6Gy ^60Co γ-rays in vitro, and the analysis of the mtDNA 4934bp deletion was made after exposure. Finally, semi-quantification PCR was used to analyze the 4934bp deletion level after 0, 2 and 6Gy irradiation with normal peripheral blood samples. The results show that 45/109 or 41% of normal human peripheral blood samples have spontaneous 4934bp deletion, and the BLAST results are proved that the 4934bp deletion locates in nt8435-nt13368 on heavy strand. The spontaneous deletion rate increases with the age （p〈0.01）. The 4934bp deletion is detected in peripheral blood samples before and after irradiation and the 4934bp deletion level is 23, 25 and 27 respectively at the irradiation dose of 0, 2 and 6Gy. These observations suggests that it would be a normal case of spontaneous 4934bp deletion in normal human peripheral blood, and the 4934bp deletion level could be enhanced along with the dose of ionizing radiation.