Effect of RF currents on cytokines production in human keratinocytes

Wound healing consists of a sequence of coordinated phases: inflammation, proliferation, and remodeling. In skin lesions, neutrophils and keratinocytes are the main cell types participating in the inflammatory phase, during which release of mediators intervening in the regulation of the subsequent regenerative phases takes place. These mediators are involved in tissue regeneration through induction of transendothelial migration, enzyme secretion, cell adhesion and T-Cell activation and cytotoxicity, as well as neutrophil accumulation at the wound site. Among these mediators, the keratinocyte synthesized chemokines RANTES, MCP-1, MIP-1 and IL-8 stand out. Although therapies applying electromagnetic fields or electric currents have been shown to have anti-inflammatory effects in a variety of experimental models and in patients through of reduced production of proimflammatory cytokines such as IFN-ϒ and increased production of IL-10, the knowledge on the biological basis of these effects is still limited. Previous studies by our group have shown that subthermal treatment with radiofrequency (RF) currents used in capacitive-resistive electric transfer (CRET) therapy promotes proliferation and migration of various cell types, such as human ADSC (stem cells), fibroblasts or keratinocytes, involved in skin regeneration. This study investigates the effects of in vitro treatment with CRET currents on cytokine production by HaCat human keratinocytes. The results reveal that, compared to sham-exposed controls, RF stimulation induces decreased production of IL-8 and increased MCP-1, without significantly affecting other chemokines such as RANTES or MIP-1. Taken together, our results indicate that due to the RF effects on the production of chemokines involved in the modulation of the inflammatory phase of wound regeneration, CRET therapy could be effective in the treatment of skin wounds.