MELATONIN AND N-TERT-BUTYL-ALPHA-PHENYLNITRONE BLOCK 60-HZ MAGNETIC-FIELD-INDUCED DNA SINGLE AND DOUBLE-STRAND BREAKS IN RAT-BRAIN CELLS

In previous research, we have found an increase in DNA single- and dou ble-strand breaks in brain cells of rats after acute exposure (two hou rs) to a sinusoidal 60-Hz magnetic field, The present experiment was c arried out to investigate whether treatment with melatonin and the spi n-trap compound N-tert-butyl-alpha-phenylnitrone (PEN) could block the effect of magnetic fields on brain cell DNA. Rats were injected with melatonin (1 mg/kg, sc) or PEN (100 mg/kg, ip) immediately before and after two hours of exposure to a 60-Hz magnetic field at an intensity of 0.5 mT. We found that both drug treatments blocked the magnetic fie ld-induced DNA single- and double-strand breaks in brain cells, as ass ayed by a microgel electrophoresis method. Since melatonin and PEN are efficient free radical scavengers, these data suggest that free radic als may play a role in magnetic field-induced DNA damage.