Institut de Radioprotection et de Sûreté Nucléaire, DEI/SECRE/LRE, Cadarache, France.
Environ Toxicol Chem. 2011 Dec;30(12):2831-7. doi: 10.1002/etc.695. Epub 2011 Oct 14.
The effects of radiation on biological systems have been studied for many years, and it is now accepted that direct damage to DNA from radiation is the triggering event leading to biological effects. In the present study, DNA damage induced by acute or chronic irradiation was compared at the cellular (zebrafish [Danio rerio] cell line ZF4) and developmental (embryo) levels. Zebrafish ZF4 cells and embryos (at 3 h postfertilization) were exposed within ranges of acute doses (0.3-2 Gy/d) or chronic dose rates (0.1-0.75 Gy/d). DNA damage was assessed by immunodetection of γ-H2AX and DNA-PK (DNA double-strand breaks) and the alkaline comet assay (DNA single-strand breaks). Zebrafish embryo development and DNA damage were examined after 120 h. At low doses, chronic irradiation induced more residual DNA damage than acute irradiation, but embryo development was normal. From 0.3 Gy, a hyper-radiosensitivity phenomenon compared to other species was shown for acute exposure with an increase of DNA damage, an impairment of hatching success, and larvae abnormalities. These results suggest a dose-dependent correlation between unrepaired DNA damage and abnormalities in embryo development, supporting the use of DNA repair proteins as predictive biomarkers of ionizing radiation exposure. This could have important implications for environmental protection.
多年来，人们一直在研究辐射对生物系统的影响，现在人们已经接受，辐射对 DNA 的直接损伤是导致生物效应的触发事件。在本研究中，比较了急性或慢性照射在细胞（斑马鱼[Danio rerio]细胞系 ZF4）和发育（胚胎）水平上引起的 DNA 损伤。将斑马鱼 ZF4 细胞和胚胎（受精后 3 小时）暴露在急性剂量（0.3-2 Gy/d）或慢性剂量率（0.1-0.75 Gy/d）范围内。通过免疫检测γ-H2AX 和 DNA-PK（DNA 双链断裂）和碱性彗星试验（DNA 单链断裂）评估 DNA 损伤。在 120 小时后检查了斑马鱼胚胎的发育和 DNA 损伤。在低剂量下，慢性照射比急性照射诱导更多的残留 DNA 损伤，但胚胎发育正常。从 0.3 Gy 开始，与其他物种相比，急性暴露表现出超放射敏感性现象，表现为 DNA 损伤增加、孵化成功率降低和幼虫异常。这些结果表明，未修复的 DNA 损伤与胚胎发育异常之间存在剂量依赖性相关性，支持将 DNA 修复蛋白作为电离辐射暴露的预测生物标志物。这对于环境保护可能具有重要意义。
