Study type: Medical/biological study (experimental study)

Exposure to 50 Hz electric fields reduces stress-induced glucocorticoid levels in BALB/c mice in a kV/m- and duration-dependent manner. med./bio.

Published in: Bioelectromagnetics 2015; 36 (4): 302-308

Aim of study (acc. to author)

The effects of exposure of mice to a 50 Hz electric field on the stress-induced plasma glucocorticoid level should be investigated.

Background/further details

The study was divided into 3 test parts, which should each examine a specific question: a) Has an electric field alone an effect on the stress-level? b) Has an electric field an effect on the stress-level induced by immobilization? c) What influence has the exposure duration?
Accordingly, for each part, mice were divided into the following groups: a) (n=5-6 per group): exposure to electric field with 1) 10 kV/m, 2) 150 kV/m, 3) sham exposure. b) (n=8 per group): immobilization and exposure to an electric field with 4) 2.5 kV/m, 5) 5 kV/m 6) 10 kV/m, 7) 50 kV/m, 8) 200 kV/m, 9) immobilization with sham-exposure, 10) only sham-exposure. c) (n=8 per group): immobilization and exposure to electric field with 10 kV/m for 11) 6 min, 12) 20 min, 13) 60 min, 14) immobilization and sham exposure, 15) only sham exposure.
Except for part c), all exposures had a duration of 60 min. In all groups, animals remained in the exposure cage for 60 minutes, regardless of the exposure condition and duration. Immobilization was conducted in the second half of these 60 minutes, respectively.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: continuous for 60 minutes
groups 1, 6 and 13
Exposure 2: 50 Hz
Exposure duration: continuous for 60 minutes
group 2
Exposure 3: 50 Hz
Exposure duration: continuous for 60 minutes
group 4
Exposure 4: 50 Hz
Exposure duration: continuous for 60 minutes
group 5
Exposure 5: 50 Hz
Exposure duration: continuous for 60 minutes
group 7
Exposure 6: 50 Hz
Exposure duration: continuous for 60 minutes
group 8
Exposure 7: 50 Hz
Exposure duration: continuous for 6 minutes
group 11
Exposure 8: 50 Hz
Exposure duration: continuous for 20 minutes
group 12

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Exposure duration continuous for 60 minutes
Additional info groups 1, 6 and 13
Exposure setup
Exposure source
Chamber cylindrical plastic cage (diameter: 200 mm, height: 100 mm) with slits (length: 100 mm, width: 5 mm) all around at intervals of 5 mm; alternative: 50 ml centrifuge tube during immobilization
Setup two stainless steel electrodes (1000 x 600 mm2) were placed over and under the cage or tube; an electrical current was applied to the upper electrode, whereas the lower electrode was grounded; electric fields had a margin of error of 1%; temperature within the cylindrical cage did not change during exposure
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 10 kV/m effective value measured - -

Exposure 2

Main characteristics
Frequency 50 Hz
Type
Exposure duration continuous for 60 minutes
Additional info group 2
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 150 kV/m effective value measured - -

Exposure 3

Main characteristics
Frequency 50 Hz
Type
Exposure duration continuous for 60 minutes
Additional info group 4
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 2.5 kV/m effective value measured - -

Exposure 4

Main characteristics
Frequency 50 Hz
Type
Exposure duration continuous for 60 minutes
Additional info group 5
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 5 kV/m effective value measured - -

Exposure 5

Main characteristics
Frequency 50 Hz
Type
Exposure duration continuous for 60 minutes
Additional info group 7
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 50 kV/m effective value measured - -

Exposure 6

Main characteristics
Frequency 50 Hz
Type
Exposure duration continuous for 60 minutes
Additional info group 8
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 200 kV/m effective value measured - -

Exposure 7

Main characteristics
Frequency 50 Hz
Type
Exposure duration continuous for 6 minutes
Additional info group 11
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 10 kV/m effective value measured - -

Exposure 8

Main characteristics
Frequency 50 Hz
Type
Exposure duration continuous for 20 minutes
Additional info group 12
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 10 kV/m effective value measured - -

Reference articles

  • Hori T et al. (2012): Effect of 50 Hz electric field in diacylglycerol acyltransferase mRNA expression level and plasma concentration of triacylglycerol, free fatty acid, phospholipid and total cholesterol.
  • Harakawa S et al. (2008): Effect of electric field in conditioned aversion response.
  • Harakawa S et al. (2005): Effects of a 50 Hz electric field on plasma lipid peroxide level and antioxidant activity in rats.

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

The results of part a) showed that an electric field alone had no significant effect on the glucocorticoid level.
In part b), a significant increase in the glucocorticoid level was found in immobilized mice without exposure (group 9) compared to the sham exposure group. A kV/m-dependent decrease from 2.5 kV/M - 10 kV/m in the glucocorticoid level was found in groups 4) - 6) compared to group 9). However, the result was only significant in group 6 (10 kV/m).
In part c), only exposure to the electric field (10 kV/m) for 20 or 60 minutes (groups 12 and 13) resulted in a significantly decreased glucocorticoid level compared to immobilization alone (group 14).
The authors conclude that exposure of mice to a 50 Hz electric field could alter the stress-induced plasma glucocorticoid level in a kV/m- and duration-dependent manner.

Study character:

Study funded by

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