Monophasic Pulsed Current Stimulation of Duty Cycle 10% Promotes Differentiation of Human Dermal Fibroblasts into Myofibroblasts

Abstract

Objective: Many clinical trials have shown the therapeutic effects of electrical stimulation (ES) in various conditions. Our previous studies showed that ES (200 μA and 2 Hz) promotes migration and proliferation of human dermal fibroblasts (HDFs). However, the effective duty cycle and the effect of ES on myofibroblast differentiation are unclear. This study aimed to investigate the relationship between duty cycle and myofibroblast differentiation. Methods: HDFs were subjected to ES (200 μA and 2 Hz) for 24 h with the duty cycle adapted at 0% (control), 10%, 50%, or 90%. α-smooth muscle actin (SMA) and transforming growth factor (TGF)-β1 mRNA and α-SMA protein expressions were assessed. Collagen gel contraction was observed for 48 h after ES initiation and the gel area was measured. Cell viability and pH of culture medium were analyzed for cytotoxicity of the ES. Results: Cell viabilities were decreased in the 50% and the 90% groups but ES did not influence on pH of culture media. ES with a duty cycle of 10% significantly promoted the mRNA expression of α-SMA and TGF-β1. α-SMA protein expression in the 10% group was also significantly higher than that of the control group. Collagen gel subjected to ES with a duty cycle of 10% was contracted. Conclusion: Duty cycle can influence on myofibroblast differentiation and ES with a duty cycle 10% is the effective for wound healing.

Efficacy of Low-frequency Monophasic Pulsed Microcurrent Stimulation Therapy in Undermining Pressure Injury: A Double-blind Crossover-controlled Study

“…34,35) In addition, the proliferation of myofibroblasts by electrical stimulation 36) is also considered to have affected the contraction of the undermining. Uemura et al 37) reported that for in vitro cell cultures using fibroblasts, a stimulation intensity of 200 µA, frequency of 2 Hz, and DF of 10% promoted differentiation into myofibroblasts and contraction of collagen gel. However, these were in vivo or in vitro studies; thus, it is unclear whether there was a di-rect effect, although it cannot be denied that MPMC therapy exerted a beneficial effect on wound healing.…”

Pulsed electrical stimulation and amino acid derivatives promote collagen gene expression in human dermal fibroblasts

“…Previous reports show that the degree of cell proliferation changes when the ES duty ratio differs (Yoshikawa Y et al 2016). Reports also suggest that the duty ratio affects myo broblast differentiation (Uemura M et al 2021). Thus, there are several electrical condition parameters, and the cellular response may vary greatly.…”

Microcurrent-Mediated Modulation of Myofibroblasts for Cardiac Repair and Regeneration

“…Electrical stimulation can have diverse effects on cells, such as facilitating myofibroblast differentiation for wound healing [ 34 , 35 , 36 ] or increasing cell proliferation and altering ECM components [ 20 , 36 , 37 ]. The different outcomes can be attributed to several factors, such as differences in the cell types studied and the current form.…”