Medical/biological study (experimental study)

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

By: Li X, Wang X, Bai L, Zhao P, Zhang M

Published in: Exp Biol Med 2019; 244 (5): 389-394

Aim of study (acc. to author)

The effects of exposure of mice to a 50 Hz magnetic field on hair follicle regrowth should be investigated.

Background/further details

Mice were depilated at dorsal skin and divided at random into a control group and exposure group (sizes of groups not mentioned). After 3, 9 and 16 days of exposure, 3 animals per group were investigated, respectively. The experiment was repeated 3 times. (remark EMF-Portal: A total of 27 animals per experiment, which is mentioned in the article, is not comprehensible.)

Endpoint

effects on hair follicle regrowth

Exposure

- 50/60 Hz
- magnetic field

Exposure	Parameters
Exposure 1: 50 Hz Exposure duration: 30 minutes per day for up to 16 days	magnetic flux density: 5 mT

Exposure 1

Main characteristics

Frequency	50 Hz
Type	magnetic field
Waveform	sinusoidal
Exposure duration	30 minutes per day for up to 16 days

Exposure setup

Exposure source	Helmholtz coils
Setup	exposure system was stored in a room at 25°C with 50 ± 10% humidity
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	5 mT	-	-	-	-

Reference articles

Li X et al. (2012): Effects of 50 Hz pulsed electromagnetic fields on the growth and cell cycle arrest of mesenchymal stem cells: an in vitro study

Exposed system:

animal
mouse/C57BL/6

Methods Endpoint/measurement parameters/methodology

morphol./histopathol. changes: histological analysis of dorsal skin: growth of hair follicles, hair length (hematoxylin-eosin stain, microscopy), detection of epidermal stem cells (via marker K15), detection of cell proliferation (via marker Ki67), detection of keratinocyte growth factors (cytokine for stimulation of epidermal stem cell growth) (immunofluorescence stain, confocal microscopy)
molecular biosynthesis: protein expression of keratinocyte growth factors in skin (Western blot)

Investigated system:

tissue slices
isolated bio./chem. substance
skin, skin extracts
investigation on living organism

Time of investigation:

after exposure

Main outcome of study (acc. to author)

The histological analysis showed that hair follicle growth was increased in the exposure group compared to the control group at all time points. The hair lenght was significantly increased in the exposure group compared to the control group after 16 days. Moreover, immunohistochemical staining revealed increased cell proliferation in the outer root sheath and hair bulb in the exposure group compared to the control group at all time points where it was co-localized with epidermal stem cells. Keratinocyte growth factors were expressed in the inner root sheath in both groups, and in Western Blot, the exposure group showed a higher expression rate at all time points than the control group (significance unclear).
The authors conclude that exposure of mice to a 50 Hz magnetic field could promote hair follicle regrowth in association with stem cells proliferation and increased keratinocyte growth factor expression.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

Binzhou Medical University, China
National Natural Science Foundation (NSFC), China

Bai WF et al. (2012): Effects of 50 Hz electromagnetic fields on human epidermal stem cells cultured on collagen sponge scaffolds
Yoon SY et al. (2011): Induction of Hair Growth by Insulin-Like Growth Factor-1 in 1,763 MHz Radiofrequency-Irradiated Hair Follicle Cells