Nelson J M, Brooks A L, Metting N F, Khan M A, Buschbom R L, Duncan A, Miick R, Braby L A
Life Sciences Center, Pacific Northwest Laboratory, Richland, Washington, 99352, USA.
Radiat Res. 1996 May;145(5):568-74.
Research to determine the effects of defined numbers of alpha particles on individual mammalian cells is helpful in understanding risks associated with exposure to radon. This paper reports the first biological data generated using the single-particle/single-cell irradiation system developed at Pacific Northwest Laboratory. Using this apparatus, CHO-K1 cells were exposed to controlled numbers of 3.2 MeV alpha particles, and biological responses of individual cells to these irradiations were quantified. Chromosomal damage, measured by the induction of micronuclei, was evaluated after no, one, two, three or five particle traversals. Exposures of up to five alpha particles had no influence on the total numbers of cells recovered for scoring. With increased numbers of alpha particles there was a decrease in the ratio of binucleated to mononucleated cells of 3.5%/hit, suggesting that alpha particles induced dose-dependent mitotic delay. A linear hit-response relationship was observed for micronucleus induction: Micronuclei/binucleated cell = 0.013 +/- 0.036 + (0.08 +/- 0.013) x D, where D is the number of particles. When the estimated dose per alpha-particle traversal was related to the frequency of induced micronuclei, the amount of chromosomal damage per unit dose was found to be similar to that resulting from exposures to alpha particles from other types of sources. Approximately 72% of the cells exposed to five alpha particles yield no micronuclei, suggesting the potential for differential sensitivity in the cell population. Additional studies are needed to control biological variables such as stage of the cell cycle and physical parameters to ensure that each cell scored received the same number of nuclear traversals.
确定特定数量的α粒子对单个哺乳动物细胞的影响的研究，有助于理解与接触氡相关的风险。本文报告了使用太平洋西北实验室开发的单粒子/单细胞辐照系统生成的首批生物学数据。利用该装置，将CHO-K1细胞暴露于受控数量的3.2 MeVα粒子，并对单个细胞对这些辐照的生物学反应进行了量化。在没有粒子穿过、一个粒子穿过、两个粒子穿过、三个粒子穿过或五个粒子穿过之后，通过微核诱导来测量染色体损伤。高达五个α粒子的暴露对用于评分的回收细胞总数没有影响。随着α粒子数量的增加，双核细胞与单核细胞的比例以每击中一次降低3.5%的幅度下降，这表明α粒子诱导了剂量依赖性的有丝分裂延迟。观察到微核诱导存在线性击中-反应关系：微核/双核细胞 = 0.013 ± 0.036 + (0.08 ± 0.013) × D，其中D是粒子数量。当将每次α粒子穿过的估计剂量与诱导微核的频率相关联时，发现单位剂量的染色体损伤量与来自其他类型源的α粒子暴露所导致的损伤量相似。暴露于五个α粒子的细胞中约72%没有产生微核，这表明细胞群体中存在差异敏感性的可能性。需要进行更多研究来控制诸如细胞周期阶段和物理参数等生物学变量，以确保每个被评分的细胞接受相同数量的核穿过。
