Journal Club: Magnetic Field Induced DNA Strand Breaks in Brain Cells of the Rat

The researchers used a pair of homemade Helmholtz coils to produce magnetic fields and exposed rats to a 0.01 mT field (Earth's magnetic field averages about 0.05 mT (50 µT) with significant regional variations) for 24 and 48 hours. The rats were sacrificed, the brains extracted and studied for single and double strand DNA breaks and apoptosis/necrosis using gel electrophoresis techniques.

Statistically significant differences were found in the number of DNA strand breaks between the exposed rats and control rats. Free radical production with NO and Fe+ ions were theorized to be the cause of the DNA strand breaks. Cell apoptosis was also found to increase following exposure. Experiments where the rats were administered free radical scavengers showed no difference between exposed and control rats. What remains to be seen, and what was not addressed in the paper is what kinds of health effects these breaks might have. This would probably be a difficult study to perform, since it would require studying a large number of rats over a long term to detect what is probably a very small effect.

Also not studied was the effect of DNA repair. The authors have clearly established free radical production as one mechanism of DNA damage in brain cells. But as is well known, cells are very good at repairing DNA damage. How much of the damaged cells would be repaired after 24 or 48 hours post-exposure? How significant would the loss of the cells be if the DNA could not be repaired and the cell died? What types of cells were most likely to incur damage? Since Fe+ free radicals were thought to be most likely involved, the authors felt that cells with higher Fe uptake would be more susceptible to damage. Authors also mentioned increased risk of neurodegenerative diseases, ALS, Alzheimer's and Parkinson's reported in previous literature due to occupational magnetic field exposure.