ELF electrostimulation on macrophages: Possibility of immunomodulation by electric field

Among the biological effects of ELF electric field, we have been interested in the effect on immune cells. If electric field can modulate the immunoresponse, it will provide a potentially useful technique in clinical practice. The effects of ELF electrostimulation on macrophages were investigated to pursue the possibility of immunomodulation using the apparatus designed for an electric field therapy. First, the current induced in the human body was estimated in a computer simulation and in an actual measurement. The maximum current density in the human body was estimated to be in the order of tens mA/m² when 10 kV was applied beneath the feet of the subject. The effect of electrostimulation on phagocytosis of macrophages was studied in vitro. The current density of the stimulation was 0.1 or 1 A/m², and the stimulation duration was 10 sec, 1 min or 1 h. Significant reductions of phagocytosis were observed in stimulated macrophages. There was not significant statistical difference between the cases of 0.1 A/m² and A/m², nor among the cases with the different durations of the stimulation. Although it is too early to judge whether the apparatus for electric field therapy is applicable to the immunomodulation, the results of this study showed the possibility that ELF electrostimulation can suppress the activity of macrophages.