Macrophage response to electrical stimulation

Many cell types respond to electrical stimuli by proliferation, changes in morphology, and release of growth factors. Specifically, neurite outgrowth increases and Schwann cells, glia of the peripheral nervous system, increase nerve growth factor release over 3 days in response to a single 50 mV/mm DC electrical stimulus. Electric stimuli has been successfully used in human crush injuries and with some limited success in rat and canine models of more severe nerve transection. Application of electrical stimuli in vivo impact not only glia and neurons, but will be applied to the injury site impacting all resident cells, including immune cells. Macrophages are rapidly recruited after injury and take much of the responsibility for inflammation at the wound site. This inflammation can impair healing. Therefore, it is important to determine how electrical stimuli influence macrophage activation and phenotype. Macrophages are very plastic, adopting a spectrum of phenotypes from an inflammatory M1 to a more supportive M2 phenotype known to aid in repair. In this work, RAW264.7 macrophage cell line was exposed to a single DC stimulation in an unactivated (M0) and activated state (M1 or M2) and changes to phenotype were characterized by PCR immediately following or 24 hrs post-stimulation. Preliminary findings suggest that DC stimulation does not alter macrophage phenotype.