Study type: Medical/biological study (experimental study)

Effects of pre- and postnatal exposure to extremely low-frequency electric fields on mismatch negativity component of the auditory event-related potentials: Relation to oxidative stress. med./bio.

Published in: Electromagn Biol Med 2016; 35 (3): 245-259

Aim of study (acc. to author)

The effects of prenatal and/or postnatal exposure of rats to a 50 Hz electric field on mismatch negativity in the EEG and oxidative brain damage should be investigated.

Background/further details

Mismatch negativity was investigated as an indicator for brain function.
Pregnant rats were divided into 4 groups: 1) only prenatal exposure, 2) only postnatal exposure, 3) prenatal and postnatal exposure, 4) sham exposed control group. 22 days after birth, male young animals were separated from their mothers, and 90 days after birth, 10 male rats per group were investigated.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: 1 hour/day during gestation until birth (22 days)
Exposure 2: 50 Hz
Exposure duration: 1 hour/day for 90 days after birth
Exposure 3: 50 Hz
Exposure duration: 1 hour/day during gestation until birth (22 days) and for 90 days after birth

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Exposure duration 1 hour/day during gestation until birth (22 days)
Additional info prenatal exposure
Exposure setup
Exposure source
  • plate capacitor
Chamber plastic cage (the animals' home cage; 42.5 cm Π26.5 cm Π18.5 cm)
Setup the parallel plate capacitor consisted of custom made copper plates (50 cm Π80 cm) plated with zinc (2 mm thickness); in order to produce an uniform field, the corners of the plates were rounded; plates were placed upright on wooden stands and positioned parallel to each other (50 cm distance); cables from AC voltage transformer were connected to the center of the plates on their outer surfaces to preserve field homogeneity; one pregnant rat or four pups in one cage were exposed at one time; the cage was placed in the center between the two plates at equal distance from the plates; the cage was suitable for free movement of pups (and mothers?) (remark EMF-Portal: the direction of the electric field is specified as "vertical" in the article although the figures show a setup with a horizontal field)
Sham exposure A sham exposure was conducted.
Additional info rats of the prenatal exposure group were sham exposed for 90 days after birth
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 12 kV/m - calculated - 11.7 - 11.89 kV/m

Exposure 2

Main characteristics
Frequency 50 Hz
Type
Exposure duration 1 hour/day for 90 days after birth
Additional info postnatal exposure
Exposure setup
Exposure source
Additional info rats of the postnatal exposure group were sham exposed during gestation
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 12 kV/m - calculated - 11.7 - 11.89 kV/m

Exposure 3

Main characteristics
Frequency 50 Hz
Type
Exposure duration 1 hour/day during gestation until birth (22 days) and for 90 days after birth
Additional info prenatal and postnatal exposure
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 12 kV/m - calculated - 11.7 - 11.89 kV/m

Reference articles

  • Aydin MA et al. (2006): The influence of continuous exposure to 50 Hz electric field on nerve regeneration in a rat peroneal nerve crush injury model.

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

The mismatch negativity amplitude was significantly decreased in all exposure groups compared to the control group, indicating an effect of the electric field exposure on the EEG of rats.
Lipid peroxidation was significantly increased in the postnatal exposure group (group 2) compared to the control group, while it was significantly decreased in the prenatal and postnatal exposure group (group 3) compared to prenatal (group 1) and postnatal exposure group.
The protein carbonyl levels were significantly decreased in group 3 compared to all other groups.
No apoptosis was found in any group and there were no differences observed in general health, food intake or body weight between the groups.
The authors conclude that prenatal and/or postnatal exposure of rats to a 50 Hz electric field might decrease mismatch negativity amplitude in the EEG. This could be partly explained by increased lipid peroxidation.

Study character:

Study funded by

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