Medical/biological study (experimental study)

Effects of long-term 50 Hz power-line frequency electromagnetic field on cell behavior in Balb/c 3T3 cells med./bio.

By: An GZ, Xu H, Zhou Y, Du L, Miao X, Jiang DP, Li KC, Guo GZ, Zhang C, Ding GR

Published in: PLoS One 2015; 10 (2): e0117672

Exposure	Parameters
Exposure 1: 50 Hz Exposure duration: 2 h/day, 5 days/week for 11 weeks	magnetic flux density: 2.3 mT effective value

Exposure 1

Main characteristics

Frequency	50 Hz
Type	magnetic field
Waveform	sinusoidal
Exposure duration	2 h/day, 5 days/week for 11 weeks

Exposure setup

Exposure source	coil(s)
Setup	setup consisted of 2 four-coil systems each placed inside a mu-metal box, respectively; both systems were inside a commercial incubator; temperature was 37°C; atmosphere consisted of 95% air, 5% CO₂ and 100% relative humidity; temperature was monitored at the location of the flasks during exposure with Pt100 probes; two fans per box were mounted to guarantee enough atmospheric exchange of the exposure chambers
Sham exposure	A sham exposure was conducted.
Additional info	current in the bifilar coils could be switched parallel for field exposure or non-parallel for sham exposure

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	2.3 mT	effective value	measured	-	-

Additional parameter details

non-uniformity of the magnetic field was less than 4%

Exposed system:

intact cell/cell culture
BALB/3T3 cells (embryonal mouse fibroblasts)

Methods Endpoint/measurement parameters/methodology

molecular biosynthesis: protein expression of Proliferating Cell Nuclear Antigen (PCNA, involved in cell proliferation) and CyclinD1 (involved in cell cycle) (SDS-PAGE, Western blot)
cell viability/cell division/proliferation: cell cycle distribution (propidium iodide staining, flow cytometry); cell viability (MTT assay); apoptosis (fluorescein staining of annexin V, commercial kit); cell transformation (soft agar assay); cell proliferation (plate assay)
morphol./histopathol. changes: cell morphology (Giemsa staining, microscopy)
cell migration in cell monolayers ("wound" was created by scraping the monolayer with a pipette tip, size of wound area was measured directly after scraping and 12 hours later, scratch test)

Investigated system:

intact cell/cell culture
supernatants of cell lysates

Time of investigation:

after exposure

Main outcome of study (acc. to author)

No significant changes were observed between exposed and sham exposed mouse fibroblasts regarding cell morphology, apoptosis, cell migration ability (scratch test) and cell transformation. However, the cell viability and the protein expression of PCNA and CyclinD1 were significantly decreased in the exposed group compared to the sham exposure. Additionally, the cell cycle distribution was significantly changed: After eleven weeks of exposure, the percentage of cells in the G1 phase and in the G2 phase was increased compared to the sham exposed cells while the percentage of cells in the S phase was decreased.
The authors conclude that long-term 50 Hz magnetic field exposure could affect cell viability and cell cycle by down-regulation of the proteins PCNA and CyclinD1.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

National Basic Research Program (Program 973), China
National Natural Science Foundation (NSFC), China

Naghibzadeh M et al. (2020): The effect of electromagnetic field on decreasing and increasing of the growth and proliferation rate of dermal fibroblast cell
Samiei M et al. (2020): The effect of electromagnetic fields on survival and proliferation rate of dental pulp stem cells
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Koziorowska A et al. (2017): Electromagnetic fields with frequencies of 5, 60 and 120 Hz affect the cell cycle and viability of human fibroblast BJ in vitro
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Effects of long-term 50 Hz power-line frequency electromagnetic field on cell behavior in Balb/c 3T3 cells med./bio.

Aim of study (acc. to author)

Background/further details

Endpoint

Exposure