中文摘要：

研究α粒子照射致人支气管上皮细胞（BEAS．2B）恶性转化中线粒体的变化。以至不同吸收剂量（0．1GV、0．25Gy、0．5Gy、1Gyα粒子照射BEAS-2B细胞），剂量率为0．223Gy／min。照射后48h检测细胞存活率，并以LD50剂量对每传10代细胞进行2次及4次照射，分别培养至40代。用软琼脂克隆检测不同照射次数细胞克隆增殖情况，用透射电镜观察超微结构改变，用Q-PCR检测线粒体DNA（mtDNA）拷贝数变化，用流式细胞仪检测线粒体ROS产生及线粒体膜电位改变。细胞经α粒子照射0．25Gy后，线粒体超微结构显著改变，软琼脂克隆形成率、mtDNA拷贝数及ROS水平随照射次数的增加而增加，线粒体膜电位则相应下降。结果显示线粒体拷贝数及ROS水平改变可作为反映细胞恶性转化程度的观察指标。

英文摘要：

To explore the role of mitochondria in the malignant transformation of immortalized human bronchial epithelial cells （BEAS-2B）, BEAS-2B cells were treated with a particles at different doses of 0.1 Gy, 0.25 Gy, 0.5 Gy and 1 Gy. And the exposure rate was 0.223 Gy/min. After the second and fourth irradiation, the cells were cultured for 40 generations. Proliferative capacity of the cells was measured by a soft agar clone test, and changes of mitochondrial morphological structure were observed by a transmission electron microscope. Mitochondrial DNA （mtDNA） copy number was detected by Q-PCR, and alterations in ROS production and mitochondrial membrane potential were analyzed by fluorescene-activated cell sorting （FACS）. After the irradiation of α particles at dose of 0.25 Gy, mitochondrial morphological structure altered significantly. Soft agar clone formation rate, mtDNA copy number and ROS production increase, while the mitochondrial membrane potential decleased with the irradiation times. The results indicated that these changes may be used as indexes reflecting the phenotype of cell transformation.