Study type: Medical/biological study (experimental study)

Extremely low-frequency electromagnetic fields affect the miRNA-mediated regulation of signaling pathways in the GC-2 cell line med./bio.

By: Liu Y, Liu WB, Liu KJ, Ao L, Cao J, Zhong JL, Liu JY
Published in: PLoS One 2015; 10 (10): e0139949
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Aim of study (acc. to author)

The effects of exposure of mouse spermatocyte-derived cells to a 50 Hz magnetic field on the microRNA expression and the possible use of microRNAs as biomarkers for magnetic field exposure should be investigated.

Background/further details

MicroRNAs are small non-coding RNAs, which regulate gene expression at the post-transcriptional level. Mouse spermatocyte-derived cells were investigated to explore the mechanisms of action of possible adverse effects of magnetic fields on the male reproductive system. Cells were divided into the following groups: exposure to a magnetic field of 1) 1 mT, 2) 2 mT and 3) 3 mT. For each group, a separate sham exposure was conducted simultaneously.
Except for microarray experiments, all tests were repeated three times.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: intermittent (5 min on/10 min off) for 72 h
Exposure 2: 50 Hz
Exposure duration: intermittent (5 min on/10 min off) for 72 h
Exposure 3: 50 Hz
Exposure duration: intermittent (5 min on/10 min off) for 72 h

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Exposure duration intermittent (5 min on/10 min off) for 72 h
Exposure setup
Exposure source
Chamber dishes in metal chamber
Setup two rectangular waveguides and two four-coil systems (two coils with 56 windings, two coils with 50 windings) generated a vertical magnetic field inside the chamber; system was composed of two identical exposure chambers (one for exposure, the other for simultaneous sham exposure); environmental conditions were constant (37°C, 5% CO2); exposure started after overnight starvation
Sham exposure A sham exposure was conducted.
Additional info the temperature difference between sham exposure and exposure chamber never exceeded 0.3°C
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 1 mT - measured - -

Exposure 2

Main characteristics
Frequency 50 Hz
Type
Exposure duration intermittent (5 min on/10 min off) for 72 h
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 2 mT - measured - -

Exposure 3

Main characteristics
Frequency 50 Hz
Type
Exposure duration intermittent (5 min on/10 min off) for 72 h
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 3 mT - measured - -

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

No significant differences were found in cell morphology, cell viability, apoptosis and cell cycle distribution between the exposure and respective sham exposure groups.
In the microarrays, 19 microRNAs with a significantly differential expression rate were found in group 1 (1 mT) (7 microRNAs were upregulated, 12 were downregulated) and 36 microRNAs were significantly differentially expressed (9 miRNAs were upregulated, and 27 were downregulated) in group 3 (3 mT) compared to the sham exposure groups. This results were confirmed by the real-time RT-PCR.
The pathway analyses showed that the identified microRNAs may regulate circadian rhythms, cytokine-cytokine receptor interactions and the p53 signaling pathway.
The authors conclude that exposure of mouse spermatocyte-derived cells to a 50 Hz magnetic field could alter the microRNA expression and that microRNAs could serve as potential biomarkers for magnetic field exposure.

Study character:

Study funded by

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