title: Fifty-hertz magnetic fields induce free radical formation in mouse bone marrow-derived promonocytes and macrophages.
abstract: Our findings show a significant increase of free radical production after exposure to 50 Hz electromagnetic fields at a flux density of 1 mT to mouse bone marrow-derived (MBM) promonocytes and macrophages, indicating the cell-activating capacity of extremely low frequency magnetic fields (ELF-MF). We demonstrate that after exposure to ELF-MF mainly superoxide anion radicals were produced, both in MBM macrophages (33%) and also in their precursor cells (24%). To elucidate whether NADPH- or NADH-oxidase functions are target proteins for MF interaction, the flavoprotein inhibitor diphenyleneiodonium chloride (DPI) was used. MF-induced free radical production was not inhibited by DPI, whereas tetradecanoylphorbolacetate (TPA)-induced free radical production was diminished by about 70%. TPA is known to induce a direct activation of NADPH-oxidase through the PKC pathway. Since DPI lacks an inhibitory effect in MF-exposed MBM cells, we suggest that 50 Hz MF stimulates the NADH-oxidase pathway to produce superoxide anion radicals, but not the NADPH pathway. Furthermore, we showed an oscillation (1-10 days) in superoxide anion radical release in mouse macrophages, indicating a cyclic pattern of NADH-oxidase activity.
authors.affiliation: Division of Environmental Physiology, Institute for Cell Biology and Biosystems Technology, University of Rostock, Albert-Einstein-Strasse 3, D-18057 Rostock, Germany.
authors.forename: Jana
authors.initials: J
authors.lastname: Rollwitz
authors.forename: Madeleine
authors.initials: M
authors.lastname: Lupke
authors.forename: Myrtill
authors.initials: M
authors.lastname: Simkó
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology* / Q000528:radiation effects*; D004574:Electromagnetic Fields; D005609:Free Radicals / Q000378:metabolism*; D008264:Macrophages / Q000166:cytology / Q000502:physiology / Q000528:radiation effects*; D051379:Mice; D009000:Monocytes / Q000166:cytology / Q000502:physiology / Q000528:radiation effects*; D009097:Multienzyme Complexes / Q000378:metabolism / Q000528:radiation effects; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism / Q000528:radiation effects; D019255:NADPH Oxidases / Q000378:metabolism / Q000528:radiation effects; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D005609:Free Radicals; D009097:Multienzyme Complexes; C023107:NADH oxidase; D009247:NADH, NADPH Oxidoreductases; D019255:NADPH Oxidases; D013755:Tetradecanoylphorbol Acetate