To study the activating capacity of 50 Hz electromagnetic fields by investigating phagocytosis and free radical production in mouse bone marrow-derived macrophages. To study whether protein kinase C-mediated signal transduction pathway is involved, co-exposures with TPA and electromagnetic fields were performed.
TPA stimulation (1 nM, 10 nM and 1 mM) was used as positive control for macrophage activation, because both phagocytic activity as well as radical production can be stimulated by TPA. TPA interacts with protein kinase C and is able to activate protein kinase C-mediated signal transduction.
Exposure duration: continuous for 30, 45 and 60 min
|Exposure duration||continuous for 30, 45 and 60 min|
|Setup||Culture dishes were placed in the center of the exposure system in a tissue culture incubator. Control samples were either run simultaneously in a separate incubator or in the same incubator with the coil system switched off.|
|Additional info||Two different exposure systems, Merritt coil system and Helmholtz coil system, were used to generate horizontally polarized magnetic fields with respect to the culture medium surface.|
|magnetic flux density||1.5 mT||maximum||measured||-||1.0 mT or 0.5 mT|
Short-time exposure (45 min) to electromagnetic fields resulted in significantly increased phagocytic uptake. Stimulation with TPA (1 nM) showed the same increased phagocytic activity as 1 mT electromagnetic fields. However, co-exposure to electromagnetic fields and TPA showed no further increase of bead uptake. Therefore the authors concluded that because of the absence of additive effects, the electromagnetic fields-induced stimulation of these macrophages does not involve the protein kinase C signal transduction pathway.
Furthermore, a significant increased superoxide production after electromagnetic field exposure was detected. This is taken for evidence of direct activation of macrophages.