Study type: Medical/biological study (experimental study)

Effect of 1.8 GHz radiofrequency electromagnetic radiation on novel object associative recognition memory in mice med./bio.

By: Wang K, Lu JM, Xing ZH, Zhao QR, Hu LQ, Xue L, Zhang J, Mei YA
Published in: Sci Rep 2017; 7: 44521
Download citation in RIS format

Aim of study (acc. to author)

To investigate the effect of exposure to a 1.8 GHz electromagnetic field on the object recognition memory and related brain parameters in mice.

Background/further details

For the novel object recognition test (NORT), mice were exposed to electromagnetic fields with a specific absorption rate of 1.98 W/kg, 2.2 W/kg, 2.42 W/kg, 2.86 W/kg, or 3.3 W/kg (n=8-12 exposed, n=7-12 sham exposed) and examined 3, 4, 5, and 8 days after the exposure. For open field (n=12 exposed, n=10 sham exposed), histological (n=16-18 exposed, n=10-21 sham exposed) and electrophysiological tests (n=12-20 exposed, n=11-16 sham exposed), animals were exposed to 3.3 W/kg and examined three days after the exposure. Every exposure group had its own sham exposure group.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 1.8 GHz
Exposure duration: 30 minutes
object recognition test (NORT)
Exposure 2: 1.8 GHz
Exposure duration: 30 minutes
object recognition test (NORT)
Exposure 3: 1.8 GHz
Exposure duration: 30 minutes
object recognition test (NORT)
Exposure 4: 1.8 GHz
Exposure duration: 30 minutes
object recognition test (NORT)
Exposure 5: 1.8 GHz
Exposure duration: 30 minutes
object recognition test (NORT), open field, histological and electrophysiological tests

Exposure 1

Main characteristics
Frequency 1.8 GHz
Type
Exposure duration 30 minutes
Additional info object recognition test (NORT)
Exposure setup
Exposure source
Chamber two cages of mice for each experimental group (exposed and sham exposed)
Setup exposure system consisted of a computer, a microwave signal source, and a two-dimensional movable loading platform; aperture plane of the horn antenna was 21.4 × 16.3 cm2
Sham exposure A sham exposure was conducted.
Additional info superficial body temperature was measured by an infrared camera and no significant difference was observed between mice exposed to a 3.3 W/kg SAR electromagnetic field and the sham exposure
Parameters
Measurand Value Type Method Mass Remarks
SAR 1.98 W/kg mean calculated brain -
electric field strength 138.8 V/m effective value measured - at a distance of 1.5 m from the antenna
power 90 W - - - -

Exposure 2

Main characteristics
Frequency 1.8 GHz
Type
Exposure duration 30 minutes
Additional info object recognition test (NORT)
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
SAR 2.2 W/kg mean calculated brain -
electric field strength 146.4 V/m effective value measured - at a distance of 1.5 m from the antenna
power 100 W - - - -

Exposure 3

Main characteristics
Frequency 1.8 GHz
Type
Exposure duration 30 minutes
Additional info object recognition test (NORT)
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
SAR 2.42 W/kg mean calculated brain -
electric field strength 153.5 V/m effective value measured - at a distance of 1.5 m from the antenna
power 110 W - - - -

Exposure 4

Main characteristics
Frequency 1.8 GHz
Type
Exposure duration 30 minutes
Additional info object recognition test (NORT)
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
SAR 2.86 W/kg mean calculated brain -
electric field strength 166.9 V/m effective value measured - at a distance of 1.5 m from the antenna
power 130 W - - - -

Exposure 5

Main characteristics
Frequency 1.8 GHz
Type
Exposure duration 30 minutes
Additional info object recognition test (NORT), open field, histological and electrophysiological tests
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
SAR 3.3 W/kg mean calculated brain -
electric field strength 179.3 V/m effective value measured - at a distance of 1.5 m from the antenna
power 150 W - - - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

Three days after exposure (SAR of 2.2 W/kg and above), the mice showed significantly enhanced memory abilities in the novel object recognition task compared to sham exposed mice. This effect consisted until the 8th day after exposure. However, no significant exposure effect was found in the motor activity.
The histological examination revealed that in exposed mice, the dendritic spine density in hippocampal pyramidal cells and the dendritic spine length in the prefrontal cortex were significantly increased compared to sham exposed mice. Electrophysiological recordings showed a significantly enhanced excitability in prefrontal cortical and hippocampal slices of exposed mice compared to sham exposed ones.
The authors conclude that a single exposure to a 1.8 GHz electromagnetic field with a SAR of 3.3 W/kg enhanced the object recognition memory in mice, accompanied by histological and electrophysiological alterations, and recommend further studies to examine a potential therapeutic effect.

Study character:

Study funded by

Related articles