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Medical/biological study (experimental study)

Effects of exposure to extremely low-frequency electromagnetic fields on spatial and passive avoidance learning and memory, anxiety-like behavior and oxidative stress in male rats.

Published in: Behav Brain Res 2018 [in press]

Aim of study (acc. to author)

To investigate the effect of exposure to a 50 Hz magnetic field on cognitive and behavioral parameters as well as on oxidative stress in rats.
Background/further details: Male rats were randomly divided into six groups (n=12 per group): 1) control group, 2) sham exposure group, 3) 1 µT magnetic field, 4) 100 µT magnetic field, 5) 500 µT magnetic field and 6) 2000 µT magnetic field. Exposure was started after one week of adaption and lasted 60 days. Behavior (elevated plus maze) was tested immediately the day after the 60 days of exposure, followed by six days training and testing in the Morris water maze. After one week of recovery, the passive avoidance test was conducted. Afterwards, blood was collected.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: 2 hours/day for 60 days
Exposure 2: 50 Hz
Exposure duration: 2 hours/day for 60 days
Exposure 3: 50 Hz
Exposure duration: 2 hours/day for 60 days
Exposure 4: 50 Hz
Exposure duration: 2 hours/day for 60 days
Exposure 1
Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration 2 hours/day for 60 days
Exposure setup
Exposure source
Setup solenoid coil had a length of 2 m, a radius of 20 cm and 1000 turns per meter; diameter of the copper wire was 2 mm
Sham exposure A sham exposure was conducted.
Additional info sham exposed animals were placed in an identical set-up but without the magnetic field
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 1 µT - measured - -
Exposure 2
Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration 2 hours/day for 60 days
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 100 µT - measured - -
Exposure 3
Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration 2 hours/day for 60 days
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 500 µT - measured - -
Exposure 4
Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration 2 hours/day for 60 days
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 2,000 µT - measured - -
Reference articles
  • Komaki A et al. (2014): Effects of exposure to an extremely low frequency electromagnetic field on hippocampal long-term potentiation in rat.
  • Salehi I et al. (2013): Exposure of rats to extremely low-frequency electromagnetic fields (ELF-EMF) alters cytokines production.
Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated material:
Investigated organ system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

No significant differences were found between the control group (group 1) and the sham exposure group (group 2). Thus the exposure groups were compared only with the control group .
In exposed rats, lipid peroxidation (groups 4 and 5), total antioxidant capacity (groups 3 and 5), total thiol molecules (groups 3, 4, 5 and 6) and total oxidant status (group 5) were significantly increased compared to the control group.
In the Morris water maze, exposed rats (groups 4 and 6) spent significantly more time in the target zone as compared to rats from the control group.
In the passive avoidance test, the latency of exposed rats (groups 4, 5, and 6) to step into the dark box was significantly increased compared to the control group. Furthermore, rats from all exposure groups spent significantly less time in the dark box compared to control rats.
In the elevated plus maze, exposed rats entered open arms significantly fewer (groups 5 and 6) and spent less time in there (groups 3, 4, 5 and 6) compared to control rats.
The authors conclude that 50 Hz magnetic fields showed no effect on the acquisition of spatial and avoidance learning but can improve memory retention of rats. Furthermore, 50 Hz magnetic fields could play a role in the development of anxiety-like behavior and oxidative stress.
Study character:

Study funded by

  • Hamadan University of Medical Sciences, Iran

Related articles

  • Gao QH et al. (2017): Beneficial effect of catechin and epicatechin on cognitive impairment and oxidative stress induced by extremely low frequency electromagnetic field .
  • Djordjevic NZ et al. (2017): Anxiety-like behavioural effects of extremely low-frequency electromagnetic field in rats.
  • Lai J et al. (2016): Effects of extremely low frequency electromagnetic fields (100 µT) on behaviors in rats.
  • Rostami A et al. (2016): Effects of 3 Hz and 60 Hz Extremely Low Frequency Electromagnetic Fields on Anxiety-Like Behaviors, Memory Retention of Passive Avoidance and Electrophysiological Properties of Male Rats.
  • Li C et al. (2014): The extremely low-frequency magnetic field exposure differently affects the AMPAR and NMDAR subunit expressions in the hippocampus, entorhinal cortex and prefrontal cortex without effects on the rat spatial learning and memory.
  • Foroozandeh E et al. (2013): Toxic effects of 50 Hz electromagnetic field on memory consolidation in male and female mice.
  • Cui Y et al. (2012): Deficits in water maze performance and oxidative stress in the hippocampus and striatum induced by extremely low frequency magnetic field exposure.
  • He LH et al. (2011): Effects of extremely low frequency magnetic field on anxiety level and spatial memory of adult rats.
  • Fu Y et al. (2008): Long-term exposure to extremely low-frequency magnetic fields impairs spatial recognition memory in mice.
  • Liu T et al. (2008): Chronic exposure to low-intensity magnetic field improves acquisition and maintenance of memory.
  • Liu T et al. (2008): Anxiogenic effect of chronic exposure to extremely low frequency magnetic field in adult rats.