Stimulation of phagocytosis and free radical production in murine macrophages by 50 Hz electromagnetic fields

Effects of 50 Hz electromagnetic fields on phagocytosis and free radical pr oduction were examined in mouse bone marrow-derived macrophages. Macrophage s were in vitro exposed to electromagnetic fields using different magnetic field densities (0.5 - 1.5 mT). Short-time exposure (45 min) to electromagn etic fields resulted in significantly increased phagocytic uptake (36.3% +/ - 15.1%) as quantified by measuring the internalization rate of latex beads . Stimulation with 1 nM 12-O-tetradecanoylphorbol-13-acetate (TPA) showed t he same increased phagocytic activity as 1 mT electromagnetic fields. Howev er, co-exposure to electromagnetic fields and TPA showed no further increas e of bead uptake, and therefore we concluded that because of the absence of additive effects, the electromagnetic fields-induced stimulation of mouse bone marrow-derived macrophages does not involve the protein kinase C signa l transduction pathway. Furthermore, a significant increased superoxide pro duction after exposure to electromagnetic fields was detected.