Saha Shreya, Woodbine Lisa, Haines Jackie, Coster Margaret, Ricket Nicole, Barazzuol Lara, Ainsbury Elizabeth, Sienkiewicz Zenon, Jeggo Penny
Genome Damage and Stability Centre, Life Sciences, University of Sussex, Brighton BN19RQ, UK.
Public Health England Centre for Radiation, Chemical and Environmental Hazards, Chilton, Didcot, Oxford OX11 0RQ, UK.
J R Soc Interface. 2014 Nov 6;11(100):20140783. doi: 10.1098/rsif.2014.0783.
The use of X-rays for medical diagnosis is enhancing exposure to low radiation doses. Exposure to extremely low-frequency electromagnetic or magnetic fields is also increasing. Epidemiological studies show consistent associations of childhood leukaemia with exposure to magnetic fields but any causal relationship is unclear. A limitation in assessing the consequence of such exposure is the availability of sensitive assays. The embryonic neuronal stem and progenitor cell compartments are radiosensitive tissues. Using sensitive assays, we report a statistically significant increase in DNA double-strand break (DSB) formation and apoptosis in the embryonic neuronal stem cell compartment following in utero exposure to 10-200 mGy X-rays. Both endpoints show a linear response. We also show that DSB repair is delayed following exposure to doses below 50 mGy compared with 100 mGy. Thus, we demonstrate in vivo consequences of low-dose radiation. In contrast to these impacts, we did not observe any significant induction of DSBs or apoptosis following exposure to 50 Hz magnetic fields (100 or 300 µT). We conclude that any DSB induction by treatment with magnetic fields is lower than following exposure to 10 mGy X-rays. For comparison, certain procedures involving computed tomography scanning are equivalent to 1-5 mGy X-rays.
X射线在医学诊断中的应用正在增加人们对低辐射剂量的暴露。暴露于极低频电磁场的情况也在增多。流行病学研究表明儿童白血病与暴露于磁场之间存在持续关联，但任何因果关系尚不清楚。评估此类暴露后果的一个限制因素是缺乏灵敏的检测方法。胚胎神经元干细胞和祖细胞区室是对辐射敏感的组织。通过使用灵敏的检测方法，我们报告称，子宫内暴露于10 - 200毫戈瑞X射线后，胚胎神经元干细胞区室中DNA双链断裂（DSB）形成和细胞凋亡在统计学上有显著增加。这两个终点均显示出线性反应。我们还表明，与100毫戈瑞相比，暴露于低于50毫戈瑞的剂量后，DSB修复会延迟。因此，我们证明了低剂量辐射的体内后果。与这些影响形成对比的是，暴露于50赫兹磁场（100或300微特斯拉）后，我们未观察到DSB或细胞凋亡有任何显著诱导。我们得出结论，磁场处理所诱导的任何DSB均低于暴露于10毫戈瑞X射线后的情况。作为比较，某些涉及计算机断层扫描的程序相当于1 - 5毫戈瑞X射线。
