Direct Current Electrical Fields Improve Experimental Wound Healing by Activation of Cytokine Secretion and Erk1/2 Pathway Stimulation

Abstract

There is growing evidence that cell behaviors can be influenced by the direct current electric fields (EFs). Some behaviors may influence wound healing directly. This study aimed to investigate the effects of EF (200 mV/mm) on immortalized nontumorigenic human epidermal (HaCaT) cells. We established a setup that can transmit an EF and maintain a stable cell culture environment. An EF was applied to HaCaT cells, and scratch-assays were performed as a model of wound healing to observe cell migration. Proliferation was evaluated by mitochondrial activity, total protein, and DNA content. Secretion of healing-associated cytokines was evaluated via cytokine arrays, and Western blot was applied to investigate signaling pathway alterations. Compared with the control group, the migration of cells exposed to EFs significantly increased (p < 0.01). After 7 days, the changes in proliferation also increased significantly (p < 0.05). The cytokine arrays revealed that granulocyte-macrophage colony-stimulating factor (GM-CSF) was the most abundant factor secreted by HaCaT following EF exposure. The signals for phospho-Erk1/2 showed a significant (p < 0.0001) increase following EF exposure. The results demonstrate that exposure of HaCaT cells to EFs has positive effects on migration, proliferation, and cytokine secretion—three important steps in wound healing—and these effects may be partially mediated by activation of the Erk1/2 signaling pathway.

Microcurrent Reverses Cigarette Smoke-Induced Angiogenesis Impairment in Human Keratinocytes In Vitro

“…The setup to transmit the MC signal was as described previously [ 15 ]. In short, a custom-made 6-well plate containing four identical electrotactic chambers was used to build the setup.…”

“…Treatments to accelerate wound healing and cure chronic wounds are actively sought, and one non-invasive and convenient treatment, electrical stimulation (ES), has been used successfully in research for clinical applications [ 11 ]. Based on the existence of endogenous electrical fields at human wound sites (created by the transepithelial potential difference (TEP)) [ 12 ], researchers have shown that electrical signals are crucial initiators and regulators of wound cell proliferation [ 13 ], migration [ 14 ], secretion function [ 15 ] and, therefore, act to accelerate wound closure [ 16 ]. Microcurrent (MC) is “an electrotherapeutic modality that uses low levels of electrical current (less than 1 mA) to facilitate circulation and cellular healing or to reduce pain or edema” [ 17 ]; it is an electrotherapy strategy involving microampere range current [ 18 ].…”

“…In vitro experiments can provide vital information; however, the transmission of MC to a cell culture system is challenging [ 29 ]. We recently established an experimental ES system to distribute electrical signals to cells in vitro while maintaining a steady cell culture environment [ 15 ]. The novel experimental system enhances reproducibility by increasing the number of parallel experimental set-ups and provides an efficient, reliable, and reproducible method for data collection.…”

“…In our previous study, we explored the effect of electric field signals on the healing-related ability of keratinocytes using the new system. We showed that the electric field enhanced keratinocyte migration, proliferation, cytokine secretion, and that these biological effects were mediated due to an activation of the MAPK signaling pathways [ 15 ].…”

Healing after Trauma—New Knowledge and Procedures for the Benefit of Our Patients

“…The publication of Lu et al shows that a direct and current electrical field improves the wound healing ability in an experimental setting with human epidermal cells [ 4 ]. The migration and proliferation of cells exposed to electrical fields increased significantly compared to control group.…”