Shimura Noriko, Kojima Shuji
Faculty of Pharmaceutical Sciences, Ohu University, Tomita-machi, Koriyama, Fukushima, Japan.
Faculty of Pharmaceutical Sciences, Department of Radiation Biosciences, Tokyo University of Science (TUS), Chiba, Japan.
Dose Response. 2018 Jun 18;16(2):1559325818777326. doi: 10.1177/1559325818777326. eCollection 2018 Apr-Jun.
We herein attempted to identify the lowest radiation dose causing molecular changes in the living body. We investigated the effects of radiation in human cells, animals, and humans. DNA double-strand breaks (DSBs) formed in cells at γ- or X-ray irradiation doses between 1 mGy and 0.5 Gy; however, the extent of DSB formation differed depending on the cell species. The formation of micronuclei (MNs) and nucleoplasmic bridges (NPBs) was noted at radiation doses between 0.1 and 0.2 Gy. Stress-responsive genes were upregulated by lower radiation doses than those that induced DNA DSBs or MN and NPBs. These γ- or X-ray radiation doses ranged between approximately 10 and 50 mGy. In animals, chromosomal aberrations were detected between 50 mGy and 0.1 Gy of low linear energy transfer radiation, 0.1 Gy of metal ion beams, and 9 mGy of fast neutrons. In humans, DNA damage has been observed in children who underwent computed tomography scans with an estimated blood radiation dose as low as 0.15 mGy shortly after examination. The frequencies of chromosomal translocations were lower in residents of high background areas than in those of control areas. In humans, systemic adaptive responses may have been prominently expressed at these radiation doses.
我们在此试图确定在活体中引起分子变化的最低辐射剂量。我们研究了辐射对人类细胞、动物和人类的影响。在γ射线或X射线照射剂量为1 mGy至0.5 Gy时，细胞中会形成DNA双链断裂（DSB）；然而，DSB形成的程度因细胞种类而异。在辐射剂量为0.1至0.2 Gy时，可观察到微核（MN）和核质桥（NPB）的形成。与诱导DNA DSB或MN和NPB形成的辐射剂量相比，较低的辐射剂量即可上调应激反应基因。这些γ射线或X射线辐射剂量范围约为10至50 mGy。在动物中，在低线性能量转移辐射剂量为50 mGy至0.1 Gy、金属离子束剂量为0.1 Gy以及快中子剂量为9 mGy时，可检测到染色体畸变。在人类中，对接受计算机断层扫描的儿童进行检查后不久发现，其估计的血液辐射剂量低至0.15 mGy时就已出现DNA损伤。高本底地区居民的染色体易位频率低于对照地区居民。在人类中，这些辐射剂量下可能已显著表现出全身适应性反应。
