ABSTRACT
Macrophages, when entering inflamed tissue, encounter low oxygen tension due to the impairment of blood supply and/or the massive infiltration of cells that consume oxygen. Previously, we showed that such macrophages release more bacteriotoxic hydrogen peroxide (H2O2) when exposed in vitro to low oxygen than when cultured at usual ambient oxygen conditions. In this study, we use this low-oxygen, inflammatory macrophage model to test the macrophages response to low-frequency magnetic fields. Low-frequency fields are clinically used for bone and wound healing and are emerging as therapy for inflammatory diseases. The acceptance of these non-invasive therapies is slow due to the lack of knowledge of the cellular targets for magnetic fields. One possible target is biologically relevant ions. The Ion Parametric Resonance (IPR) concept predicts that specific externally applied AC and DC magnetic fields will resonate with the cyclotron motion of ions. This concept is supported by experimental evidence, especially on a neuronal cell line. Using our macrophage model, we tested AC and DC magnetic fields at the amplitude ratio and frequency predicted by the IPR model for resonance with hydrogen, magnesium and manganese ions. Under these conditions, we found a significant increase in H2O2 release compared to control cells. Magnetic field exposure conditions in which parameters differed from the predictions of the IPR model showed no, or a smaller difference, with respect to the control cultures. These data indicate that magnetic fields can enhance H2O2 release of inflammatory macrophages, which is consistent with the predictions of the IPR model.
