Study type: Medical/biological study (experimental study)

Extremely low-frequency electric field suppresses not only induced stress response but also stress-related tissue damage in mice. med./bio.

Published in: Sci Rep 2020; 10 (1): 20930

Aim of study (acc. to author)

The effects of exposure of mice to a 50 Hz electric field on immobilization-induced stress and stress-related tissue damage should be investigated.

Background/further details

In this publication, results from 32 individual experiments were evaluated in a pooled analysis. Data from Hori et al. 2015, Harakawa et al. 2017, Hori et al. 2017, Hori et al. 2018, Harakawa et al. 2020 and from unpublished experiments were used. For glucocorticoid level analysis, data from all 32 experiments were pooled. For the haematological analyses, data from 6 experiments (all unpublished) were pooled, and for the metabolome analysis, data from one unpublished experiment were used.
Most experiments used the following groups: 1) immobilization stress and exposure to the electric field, 2) exposure to the electric field only, 3) immobilization stress only, 4) control group.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: 60 minutes

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Exposure duration 60 minutes
Exposure setup
Exposure source
Chamber cylindrical plastic cage (diameter: 200 mm, height: 100 mm) with slits (length: 100 mm, width: 5 mm) throughout at intervals of 5 mm to prevent smudges (from faeces or saliva) from disturbing the formation of a stable electric field; stress was induced by the immobilisation of each mouse separately inside a 50 mL centrifuge tube
Setup the exposure system consisted of two stainless steel electrodes (1,000 mm × 600 mm) that were placed above and under the cylindrical cage; current was applied to the upper electrode, whereas the lower electrode was grounded; separate cages and tubes were used for each animal; the temperature inside the cage was 25 °C ± 3 °C during exposure or sham exposure; the humidity was maintained between 45 and 55%; the electric field intensity had an error margin of ± 0.1% inside the cage; mice in the co-exposure group were immobilised during the second half (30 min) of the exposure period
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 10 kV/m - measured - -

Reference articles

  • Harakawa S et al. (2020): Gender and Age Differences in the Suppressive Effect of a 50 Hz Electric Field on the Immobilization-Induced Increase of Plasma Glucocorticoid in Mice.
  • Hori T et al. (2018): Characterization of the suppressive effects of extremely-low-frequency electric fields on a stress-induced increase in the plasma glucocorticoid level in mice.
  • Hori T et al. (2017): Configuration-dependent variability of the effect of an electric field on the plasma glucocorticoid level in immobilized mice.
  • Harakawa S et al. (2017): Time-dependent changes in the suppressive effect of electric field exposure on immobilization-induced plasma glucocorticoid increase in mice.
  • Hori T et al. (2015): Exposure to 50 Hz electric fields reduces stress-induced glucocorticoid levels in BALB/c mice in a kV/m- and duration-dependent manner.

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 plasma glucocorticoid level was significantly reduced in immobilized mice exposed to the electric field (group 1) compared to immobilized mice without electric field exposure (group 3). In mice only exposed to the electric field (group 2) the glucocorticoid level was slightly but significantly increased compared to the control group. The immobilisationinduced increase in lactate dehydrogenase, glutamic oxaloacetic transaminase, and glutamic pyruvic transaminase level (markers of tissue damage) was significantly suppressed in immobilized mice exposed to the electric field. In the metabolome analysis, the changes in corticosterone, leukotrienes, and hydroxyeicosatetraenoic acids (markers of inflammation) showed a pattern similar to that of the plasma glucocorticoid level.
The authors concluded that exposure to a 50 Hz electric field might reduce the stress and stressinduced tissue damage and inflammation in immobilized mice. However, it might promote stress in the absence of immobilization-induced stress.

Study character:

Study funded by

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