60 Hz magnetic field exposure induces DNA crosslinks in rat brain cells.
In previous research, we found an increase in DNA strand breaks in brain cells of rats acutely exposed to a 60 Hz magnetic field (for 2 h at an intensity of 0.5 mT). DNA strand breaks were measured with a microgel electrophoresis assay using the length of DNA migration as an index. In the present experiment, we found that most of the magnetic field-induced increase in DNA migration was observed only after proteinase-K treatment, suggesting that the field caused DNA-protein crosslinks. In addition, when brain cells from control rats were exposed to X-rays, an increase in DNA migration was observed, the extent of which was independent of proteinase-K treatment. However, the X-ray-induced increase in DNA migration was retarded in cells from animals exposed to magnetic fields even after proteinase-K treatment, suggesting that DNA-DNA crosslinks were also induced by the magnetic field. The effects of magnetic fields were also compared with those of a known DNA crosslink-inducing agent mitomycin C. The pattern of effects is similar between the two agents. These data suggest that both DNA-protein and DNA-DNA crosslinks are formed in brain cells of rats after acute exposure to a 60 Hz magnetic field.
Singh
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Bioelectromagnetics Research Laboratory, Department of Bioengineering, University of Washington, Seattle, WA, USA. narendra@u.washington.edu
Lai
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H
D000818:Animals; D001921:Brain / Q000166:cytology / Q000378:metabolism / Q000528:radiation effects*; D003432:Cross-Linking Reagents / Q000494:pharmacology; D004247:DNA / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects*; D004574:Electromagnetic Fields / Q000009:adverse effects*; D004586:Electrophoresis; D019286:Endopeptidase K / Q000378:metabolism; D008297:Male; D016685:Mitomycin / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014965:X-Rays / Q000009:adverse effects
D003432:Cross-Linking Reagents; D016685:Mitomycin; D004247:DNA; D019286:Endopeptidase K