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观察~(125)I籽源持续低剂量率照射诱导人肺癌细胞损伤的旁效应。选择对高剂量率外照射敏感性不同的A549人肺腺癌细胞和NCI-H446人小细胞肺癌细胞,采用~(125)I籽源离体照射细胞模式,将直接受照细胞与未受照细胞共培养24h,应用CB微核法和γH2AX荧光免疫分析法,检测2Gy和4Gy ~(125)I籽源持续低剂量率照射诱导人肺癌细胞的微核形成和DNA双链断裂水平。结果表明,~(125)I籽源照射能显著诱导A549和NCI-H446细胞的微核形成率和γH2AX位点形成率增加的旁效应,显示增强对肿瘤细胞的杀伤作用。旁效应强弱与累积照射剂量、肿瘤细胞的辐射敏感性相关:对高剂量率外照射敏感的NCI-H446细胞对低剂量率照射及其旁效应的敏感性高于A549细胞。但与直接辐射效应相比,~(125)I籽源照射诱导A549细胞旁效应高于NCI-H446细胞,这两种细胞的辐射旁效应均随累积照射剂量增加而降低,提示介导旁效应的信号因子水平可能随细胞损伤程度的增加而下降。
To observe the side effects of ~ (125) I seeds on low lung cancer cell injury induced by low dose radiation. The A549 human lung adenocarcinoma cells and NCI-H446 human small cell lung cancer cells with different sensitivity to high dose radiation were selected. In vitro irradiated cell model with ~ (125) I seeds, The cells were co-cultured for 24 hours. The micronuclei formation and DNA double-strand breaks of human lung cancer cells were detected by using CB micronucleus test and γH2AX fluorescence immunoassay to detect the sustained low dose rate of 2Gy and 4Gy 125 I seeds. The results showed that irradiation with ~ (125) I seed could significantly induce the micronuclei formation rate and the side effects of γH2AX site formation in A549 and NCI-H446 cells, indicating the enhanced cytotoxicity on tumor cells. The effect of side effects was related to cumulative radiation dose and the radiosensitivity of tumor cells. NCI-H446 cells sensitive to high dose radiation exposure were more sensitive to low dose radiation and its side effects than A549 cells. However, compared with the direct radiation effect, the (125) I seed-source irradiation induced a higher degree of side effects in A549 cells than in NCI-H446 cells. The radiation side effects of these two cells decreased with the increase of cumulative irradiation dose, Of the signal factor levels may decline with the increase of cell damage.