Sollazzo Alice, Brzozowska Beata, Cheng Lei, Lundholm Lovisa, Haghdoost Siamak, Scherthan Harry, Wojcik Andrzej
a Centre for Radiation Protection Research, Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden.
b Department of Biomedical Physics, Faculty of Physics, University of Warsaw, Warsaw, Poland.
Radiat Res. 2017 Oct;188(4):400-411. doi: 10.1667/RR14803.1. Epub 2017 Aug 18.
Survivors of the atomic bombings of Hiroshima and Nagasaki are monitored for health effects within the Life Span Study (LSS). The LSS results represent the most important source of data about cancer effects from ionizing radiation exposure, which forms the foundation for the radiation protection system. One uncertainty connected to deriving universal risk factors from these results is related to the problem of mixed radiation qualities. The A-bomb explosions generated a mixed beam of the sparsely ionizing gamma radiation and densely ionizing neutrons. However, until now the possible interaction of the two radiation types of inducing biological effects has not been taken into consideration. The existence of such interaction would suggest that the application of risk factors derived from the LSS to predict cancer effects after pure gamma-ray irradiation (such as in the Fukushima prefecture) leads to an overestimation of risk. To analyze the possible interaction of radiation types, a mixed-beam exposure facility was constructed where cells can be exposed to sparsely ionizing X rays and densely ionizing alpha particles. U2OS cells were used, which are stably transfected with a plasmid coding for the DNA repair gene 53BP1 coupled to a gene coding for the green fluorescent protein (GFP). The induction and repair of DNA damage, which are known to be related to cancer induction, were analyzed. The results suggest that alpha particles and X rays interact, leading to cellular and possibly cancer effects, which cannot be accurately predicted based on assuming simple additivity of the individual mixed-beam components.
广岛和长崎原子弹爆炸幸存者在“寿命研究”（LSS）中接受健康影响监测。LSS结果是关于电离辐射暴露致癌影响最重要的数据来源，为辐射防护体系奠定了基础。从这些结果推导通用风险因素存在的一个不确定性与混合辐射品质问题有关。原子弹爆炸产生了由稀疏电离的伽马辐射和密集电离的中子组成的混合束。然而，到目前为止，尚未考虑这两种辐射类型在诱导生物效应方面可能存在的相互作用。这种相互作用的存在表明，应用从LSS得出的风险因素来预测纯伽马射线照射（如在福岛县）后的致癌影响会导致风险高估。为了分析辐射类型的可能相互作用，构建了一个混合束暴露设施，在其中细胞可以暴露于稀疏电离的X射线和密集电离的α粒子。使用了U2OS细胞，这些细胞用编码与绿色荧光蛋白（GFP）编码基因偶联的DNA修复基因53BP1的质粒进行了稳定转染。分析了已知与癌症诱发相关的DNA损伤的诱导和修复。结果表明，α粒子和X射线相互作用，导致细胞效应以及可能的致癌效应，而基于假设单个混合束成分的简单加和无法准确预测这些效应。
