title: Increased apoptosis and DNA double-strand breaks in the embryonic mouse brain in response to very low-dose X-rays but not 50 Hz magnetic fields.
abstract: 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.
authors.affiliation: Genome Damage and Stability Centre, Life Sciences, University of Sussex, Brighton BN19RQ, UK.
authors.forename: Shreya
authors.initials: S
authors.lastname: Saha
authors.affiliation: Genome Damage and Stability Centre, Life Sciences, University of Sussex, Brighton BN19RQ, UK.
authors.forename: Lisa
authors.initials: L
authors.lastname: Woodbine
authors.affiliation: Public Health England Centre for Radiation, Chemical and Environmental Hazards, Chilton, Didcot, Oxford OX11 0RQ, UK.
authors.forename: Jackie
authors.initials: J
authors.lastname: Haines
authors.affiliation: Public Health England Centre for Radiation, Chemical and Environmental Hazards, Chilton, Didcot, Oxford OX11 0RQ, UK.
authors.forename: Margaret
authors.initials: M
authors.lastname: Coster
authors.affiliation: Genome Damage and Stability Centre, Life Sciences, University of Sussex, Brighton BN19RQ, UK.
authors.forename: Nicole
authors.initials: N
authors.lastname: Ricket
authors.affiliation: Genome Damage and Stability Centre, Life Sciences, University of Sussex, Brighton BN19RQ, UK.
authors.forename: Lara
authors.initials: L
authors.lastname: Barazzuol
authors.affiliation: Public Health England Centre for Radiation, Chemical and Environmental Hazards, Chilton, Didcot, Oxford OX11 0RQ, UK.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Ainsbury
authors.affiliation: Public Health England Centre for Radiation, Chemical and Environmental Hazards, Chilton, Didcot, Oxford OX11 0RQ, UK.
authors.forename: Zenon
authors.initials: Z
authors.lastname: Sienkiewicz
authors.affiliation: Genome Damage and Stability Centre, Life Sciences, University of Sussex, Brighton BN19RQ, UK p.a.jeggo@sussex.ac.uk.
authors.forename: Penny
authors.initials: P
authors.lastname: Jeggo
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000528:radiation effects*; D001921:Brain / Q000196:embryology* / Q000378:metabolism; D053903:DNA Breaks, Double-Stranded / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D004622:Embryo, Mammalian / Q000378:metabolism* / Q000473:pathology; D005260:Female; D060526:Magnetic Fields; D051379:Mice; D058953:Neural Stem Cells / Q000378:metabolism* / Q000473:pathology; D014965:X-Rays / Q000009:adverse effects
keywords: DNA damage response; DNA double-strand breaks; apoptosis; extremely low-frequency electromagnetic fields; low-dose radiation