Medical/biological study (experimental study)

Effects of 2.4 GHz radiofrequency radiation emitted from Wi-Fi equipment on microRNA expression in brain tissue med./bio.

By: Dasdag S, Akdag MZ, Erdal ME, Erdal N, Ay OI, Ay ME, Yilmaz SG, Tasdelen B, Yegin K

Published in: Int J Radiat Biol 2015; 91 (7): 555-561

Aim of study (acc. to author)

The effects of a chronic exposure of rats to a 2.4 GHz electromagnetic field (WLAN) on the expression rates of some microRNAs in the brain should be investigated.

Background/further details

MicroRNAs are small, non-coding RNA molecules, which play an important role in growth, differentiation, proliferation and cell death by influencing the gene expression in cells.
Rats were divided in 2 groups (n=8 each): 1) exposure and 2) sham exposure.
All measurements were conducted in triplicates.

Endpoint

molecular biosynthesis: microRNA expression in the brain

Exposure

- 2.4 GHz
- W-LAN/WiFi

Exposure	Parameters
Exposure 1: 2.4 GHz Exposure duration: continuous for 24 hours/day for 12 months	power: 100 mW peak value power: 50 mW effective value SAR: 4,000 µW/kg peak value SAR: 1,510 µW/kg average over mass (1 g) SAR: 1,030 µW/kg average over mass (10 g) SAR: 141.4 µW/kg effective value (whole body) SAR: 7,127 µW/kg maximum (whole body)

Exposure 1

Main characteristics

Frequency	2.4 GHz
Type	electromagnetic field
Charakteristic	far field
Exposure duration	continuous for 24 hours/day for 12 months
Additional info	WiFi or WLAN signal

Exposure setup

Exposure source	dipole antenna
Distance between exposed object and exposure source	50 cm
Chamber	plexiglass cage (55 x 32 x 20 cm)
Setup	rats could move freely in cage; WLAN signal generator was connected to a tuned half-wavelength dipole antenna positioned in front of a reflector plate to direct the signal to the cage; a temperature of 22°C and a relative humidity of 45% were maintained; cage was surrounded with electromagnetic absorber material backed by metal to isolate outdoor electromagnetic fields
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power	100 mW	peak value	-	-	-
power	50 mW	effective value	-	-	-
SAR	4,000 µW/kg	peak value	calculated	-	-
SAR	1,510 µW/kg	average over mass	calculated	1 g	-
SAR	1,030 µW/kg	average over mass	calculated	10 g	-
SAR	141.4 µW/kg	effective value	calculated	whole body	-
SAR	7,127 µW/kg	maximum	calculated	whole body	-

Exposed system:

animal
rat/Wistar albino
whole body

Methods Endpoint/measurement parameters/methodology

molecular biosynthesis: expression rates of the microRNAs rno-miR-26b-5p, rno-miR-9-5p, rno-miR-29a-3p, rno-miR-106b-5p, rno-miR-107, rno-miR-125a-3p (quantitative real-time RT-PCR)

Investigated system:

DNA/RNA
brain tissue, microRNAs

Investigated organ system:

brain/CNS

Time of investigation:

after exposure

Main outcome of study (acc. to author)

The expression rates of rno-miR-106b-5p and rno-miR-107 were significantly decreased in the exposure group in comparison to the sham exposure group.
The authors conclude that a chronic exposure of rats to a 2.4 GHz electromagnetic field (WLAN) could influence the expression rates of some microRNAs in the brain with possibly adverse consequences for the brain.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

not stated/no funding

Dasdag S et al. (2015): Long term and excessive use of 900 MHz radiofrequency radiation alter microRNA expression in brain
Yang XS et al. (2012): Exposure to 2.45 GHz electromagnetic fields elicits an HSP-related stress response in rat hippocampus
Paparini A et al. (2008): No evidence of major transcriptional changes in the brain of mice exposed to 1800 MHz GSM signal
Nittby H et al. (2008): Exposure to radiation from global system for mobile communications at 1,800 MHz significantly changes gene expression in rat hippocampus and cortex
Zhao R et al. (2007): Studying gene expression profile of rat neuron exposed to 1800 MHz radiofrequency electromagnetic fields with cDNA microassay
Belyaev IY et al. (2006): Exposure of rat brain to 915 MHz GSM microwaves induces changes in gene expression but not double stranded DNA breaks or effects on chromatin conformation
Fritze K et al. (1997): Effect of global system for mobile communication microwave exposure on the genomic response of the rat brain