Cellular detection of 50 Hz magnetic fields and weak blue light: effects on superoxide levels and genotoxicity

We tested the hypothesis that the effects of 50 Hz magnetic fields (MFs) on superoxide levels and genotoxicity depend on the presence of blue light.

Human SH-SY5Y neuroblastoma cells were exposed to a 50 Hz, 100 μT MF with or without non-phototoxic level of blue light for 24 h. We also studied whether these treatments alter responses to menadione, an agent that induces mitochondrial superoxide (O₂^{• -}) production and DNA damage. Micronuclei, proliferation, viability, cytosolic and mitochondrial O₂^{• -} levels were assessed.

MF (without blue light) increased cytosolic O₂^{• -} production and blue light suppressed this effect. Mitochondrial O₂^{• -} production was reduced by both MF and blue light, but these effects were not additive. Micronucleus frequency was not affected by blue light or MF alone, but blue light (significantly when combined with MF) enhanced menadione-induced micronuclei.

The original simple hypothesis (blue light is needed for MF effects) was not supported, but interaction of MF and blue light was nevertheless observed. The results are consistent with MF effects on light-independent radical reactions.