Journal Club: Magnetic field-induced DNA strand breaks in brain cells of the rat

Ok, this one is a little bit out of my field, but the topic intrigued me. Found the article through a posting at ScienceDaily.

I'm always a little bit sceptical about claims on the effects of EM fields on tissue and the brain in particular. Mostly because many of the studies that show an effect use conditions that the majority of people aren't exposed to in real life for significant periods of time. And there really isn't a lot of energy in low frequency EM radiation (in the radio wave and low frequency microwave end of the spectrum) to do much more than re-arrange electron configurations. Maybe that's enough though. Who knows. It's a lot like extrapolating the effects of low level and chronic radiation exposure when all you've got is data from high level and acute exposures.

The article (Lai H, Singh N P, "Magnetic Field-Induced DNA Strand Breaks in Brain Cells of the Rat", Environ Health Perspect, publication pending, doi:10.1289/ehp.6355) has been accepted for publication, but hasn't been published yet. The PDF of the pre-publication version of the article is available here for the time being.

Going to try to read this one over the weekend and see what interesting tidbits it contains.


In previous research, we found that rats acutely (2 hrs) exposed to a 60-Hz sinusoidal magnetic field at intensities of 0.1 - 0.5 mT showed increases in DNA single and double strand breaks in their brain cells. Further research showed that these effects could be blocked by pretreating the rats before exposure with the free radical scavengers melatonin and N-tert-butyl-α-phenylnitrone, suggesting the involvement of free radicals. In the present study, effects of magnetic field exposure on brain cell DNA in the rat were further investigated. We found that: (1) Exposure to a 60-Hz magnetic field at 0.01 mT for 24 hrs caused a significant increase in DNA single and double strand breaks. Prolonging the exposure to 48 hrs caused a larger increase. This indicates that the effect is cumulative. (2) Treatment with Trolox (a vitamin E analog) or 7-nitroindazole (a nitric oxide synthase inhibitor) blocked magnetic field-induced DNA strand breaks. These data further support a role of free radicals on the effects of magnetic fields. (3) Treatment with the iron-chelator deferiprone also blocked the effects of magnetic field on brain cell DNA, suggesting the involvement of iron. (4) Acute magnetic field exposure increased apoptosis and necrosis of brain cells in the rat. We hypothesize that exposure to a 60-Hz magnetic field initiates an iron-mediated process (e.g., the Fenton reaction) that increases free radical formation in brain cells, leading to DNA strand breaks and cell death. This hypothesis could have an important implication on the possible health effects associated with exposure to extremely-low frequency magnetic fields in the public and occupational environments.