Study type: Medical/biological study (experimental study)

miRNA expression profile is altered differentially in the rat brain compared to blood after experimental exposure to 50 Hz and 1 mT electromagnetic field. med./bio.

Published in: Prog Biophys Mol Biol 2018; 132: 35-42

Aim of study (acc. to author)

To examine whether long-term exposure of rats to a 50 Hz magnetic field has an influence on the expression level of miRNAs in blood and brain tissue.

Background/further details

MicroRNAs (miRNA) are small, non-coding RNA molecules, which play a critical role in gene regulation. In this study, miRNAs related to brain and human diseases were analyzed.
Eight groups of rats were examined (n=8, respectively): 1) adult (10 weeks old) sham exposed female, 2) young (3 weeks old) sham exposed female, 3) adult sham exposed male, 4) young sham exposed male, 5) adult magnetic field exposed female, 6) young magnetic field exposed female, 7) adult magnetic field exposed male and 8) young magnetic field exposed male.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: 4 hours/day on 60 consecutive days

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration 4 hours/day on 60 consecutive days
Exposure setup
Exposure source
Chamber respectively 4 rats in a polycarbonate cage (26 x 17 x 13 cm3)
Setup Helmholtz coil apparatus was placed in a Faraday cage (70 x 65 x 65 cm3) to shield against electric fields components, electrical noise, and vibrations; diameter of coils was 42.75 cm and a gap of 21.375 cm; coils were made of electrically and thermally insulated copper wire (2.2 mm) and constisted of 160 turns; temperature was 22-24°C with no significant difference between experiments
Sham exposure A sham exposure was conducted.
Additional info geomagnetic field of 50 µT
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 1 mT - measured - ± 0.02 mT

Reference articles

  • Gurgul S et al. (2008): Deterioration of bone quality by long-term magnetic field with extremely low frequency in rats.

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

In young exposed females (group 6), adult exposed males (group 7), and young exposed males (group 8), significant differences (down-regulation and up-regulation) in the expression of diverse miRNAs were found when compared to the corresponding sham exposure groups (groups 2, 3, 4).
The authors conclude that 50 Hz magnetic fields could influence the miRNA expression in the brain and blood of rats and that these altered expression levels differ depending on age and are differently down-regulated or up-regulated in blood and brain.

Study character:

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