Exposure to 50 Hz electromagnetic fields enhances hair follicle regrowth in C57BL/6 mice

Abstract

Many studies have suggested that electromagnetic field activity affects the cellular activity of many types of cells involved in forming hair follicles. However, the bio-effects of electromagnetic fields on hair follicle growth have not been fully elucidated. This present study was designed to determine whether 50 Hz electromagnetic fields increased hair follicle regrowth. In this experiment, C57BL/6 mice were used to present the model of depilation-induced hair follicle cycling, and then those mice were divided at random into the control group and the electromagnetic field group. After electromagnetic field (50 Hz, 5 mT) exposure for 16 days, the skin specimens of the mice were harvested to assess for hair regrowth, and epidermal stem cells proliferation was evaluated by immunofluorescence staining. The expression and location of keratinocyte growth factors were also tested. Our results showed that, compared to the control, the hair club formed faster on the 3rd day, and most of the hair shafts erupted earlier from the pore in the epidermis on the 9th day after depilation, and the hairs length was significantly longer on the 16th day within the electromagnetic field group. After electromagnetic field treatment, there were more Ki67+ cells in the outer root sheath and hair bulb where it co-localized with K15+ cells compared to the control. Keratinocyte growth factors were expressed in the inner root sheath in both groups, and the electromagnetic field group showed more expression of keratinocyte growth factors. Our data suggested that the hair-growth-promoting effect of the 50 Hz electromagnetic field was observed in depilation-induced hair follicles cycling, which was associated with 50 Hz electromagnetic field enhancing K15+ stem cells proliferation and increased keratinocyte growth factor expression. Impact statement In this study, our experiments confirmed that 50 Hz EMF affected hair follicle regrowth, and 50 Hz EMF enhanced K15+ stem cells proliferation in the hair bulb and follicular outer root sheath of hair follicles. Those results indicated that 50 Hz EMF may be beneficial for functional healing of hair loss.