内照射低浓度氚水对人乳腺上皮细胞的低剂量效应。

The low dose effects of human mammary epithelial cells induced by internal exposure to low radioactive tritiated water.

机构信息

Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, PR China; Collaborative Innovation Center of Radiation Medicine, Jiangsu Higher Education Institutions, Suzhou 215000, PR China.

Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, PR China.

出版信息

Toxicol In Vitro. 2019 Dec;61:104608. doi: 10.1016/j.tiv.2019.104608. Epub 2019 Jul 23.

DOI:10.1016/j.tiv.2019.104608

PMID:31348984

Abstract

Tritium is an important radioactive waste which needs to be monitored for radiation protection. Due to long biological half-life of organically bound tritium (OBT), the adverse consequence caused by chronic exposure of tritiated water (HTO) attracts concern. In this study, fibroblast cells were exposed to 2 × 10 Bq/ml HTO to investigate the cellular behaviors. The dose relationship of survival fraction and γH2AX foci was a "U-shaped" curve. And the results of γH2AX intensity produced by ICCM, which was obtained from different doses, demonstrated bystander signal accounted for the protective effects induced by intermediate dose of 100 mGy. The comparison of temporal kinetics and spatial dynamics of DNA repair between tritium β-rays and γ-rays showed longer time was need for the dephosphorylation of H2AX protein after HTO exposure. It indicated complex cluster DSBs induced by tritium β-rays at the low dose impaired efficient recovery of DNA damage, which bear responsibility for the persistence of residual foci after low dose expsoure. It suggests after exposed to low dose radiation cells prefer to eliminate damage population to avoid DNA damage increasing the mutation potential.

摘要

氚是一种重要的放射性废物，需要进行辐射防护监测。由于有机结合氚（OBT）的生物半衰期较长，氚水（HTO）的慢性暴露所造成的不良后果引起了人们的关注。在这项研究中，用 2×10 Bq/ml 的 HTO 处理成纤维细胞，以研究细胞行为。存活分数与 γH2AX 焦点的剂量关系呈“U 形”曲线。并且，通过 ICCM 获得的不同剂量产生的 γH2AX 强度的结果表明，100 mGy 中间剂量诱导的旁观者信号占中等剂量诱导的保护效应。氚 β射线和 γ射线的 DNA 修复的时程动力学和空间动力学的比较表明，HTO 暴露后 H2AX 蛋白去磷酸化需要更长的时间。这表明低剂量氚β射线诱导的复杂簇 DSBs 会损害 DNA 损伤的有效恢复，这是低剂量暴露后残留焦点持续存在的原因。这表明，细胞在暴露于低剂量辐射后，更倾向于消除损伤群体，以避免 DNA 损伤增加突变的可能性。