Study type: Medical/biological study (experimental study)

2100-MHz electromagnetic fields have different effects on visual evoked potentials and oxidant/antioxidant status depending on exposure duration. med./bio.

Published in: Brain Res 2016; 1635: 1-11

Aim of study (acc. to author)

The effects of exposure of rats to a 2100 MHz electromagnetic field on visual evoked potentials and oxidative stress in the brain should be investigated.

Background/further details

Male rats were divided into 4 groups (n=14 each): 1) exposure to the electromagnetic field for 1 week, 2) sham exposure for 1 week, 3) exposure to the electromagnetic field for 10 weeks, 4) sham exposure for 10 weeks. 24 hours after the end of exposure, visual evoked potentials were recorded and subsequently, rats were killed and the brain was investigated.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 2,100 MHz
Modulation type: pulsed
Exposure duration: 2 hours/day for 7 days
Exposure 2: 2,100 MHz
Modulation type: pulsed
Exposure duration: 2 hours/day for 10 weeks

Exposure 1

Main characteristics
Frequency 2,100 MHz
Type
Exposure duration 2 hours/day for 7 days
Modulation
Modulation type pulsed
Repetition frequency 217 Hz
Additional info

GSM simulation

Exposure setup
Exposure source
  • monopole
Distance between exposed object and exposure source 10 cm
Chamber shielded room
Setup the antenna, which was connected to the signal generator, was placed on a wooden table at the center of a plexiglass carousel; rats were placed in the carousel and restrained in plexiglass tubes with air holes with heads oriented towards the antenna
Sham exposure A sham exposure was conducted.
Additional info sham exposed rats were housed in a separate room under the same conditions for equal durations
Parameters
Measurand Value Type Method Mass Remarks
power 2 W peak value - - -
electric field strength 27.15 V/m minimum measured - around head
electric field strength 35.2 V/m maximum measured - around head
SAR 0.57 W/kg minimum measured and calculated partial body at the level of the head
SAR 0.95 W/kg maximum measured and calculated partial body at the level of the head

Exposure 2

Main characteristics
Frequency 2,100 MHz
Type
Exposure duration 2 hours/day for 10 weeks
Modulation
Modulation type pulsed
Repetition frequency 217 Hz
Additional info

GSM simulation

Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
power 2 W peak value - - -
electric field strength 27.15 V/m minimum measured - around head
electric field strength 35.2 V/m maximum measured - around head
SAR 0.57 W/kg minimum measured and calculated partial body at the level of the head
SAR 0.95 W/kg maximum measured and calculated partial body at the level of the head

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

The latencies of all visual evoked potentials were significantly shortened in group 1 compared to the sham exposure group, while they were significantly increased (except P1) in group 3 compared to the sham exposure group.
Lipid peroxidation was significantly decreased after one week of exposure to the electromagnetic field (group 1) compared to the respective sham exposure group (group 2), while it was significantly increased after 10 weeks of exposure (group 3) compared to the sham exposure group (group 4). The enzyme activities of catalase and glutathione peroxidase as well as the levels of nitric oxide and glutathione were significantly increased in group 1, while the superoxide dismutase enzyme activity was significantly decreased compared to the sham exposure group. In group 3, catalase and glutathione peroxidase enzyme activities and the level of nitric oxide were significantly decreased compared to the sham exposure group.
There was a significant positive correlation between all visual evoked potentials latencies and lipid peroxidation in the brain.
The authors conclude that exposure of rats to 2100 MHz electromagnetic field might alternate visual evoked potentials and induce oxidative stress in the brain depending on the exposure duration. Thus, short term exposure (1 week) might have a protective effect, while long term exposure (10 weeks) might have an adverse effect on the oxidative status in the brain.

Study character:

Study funded by

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