Effects of Single and Repeated Exposure to a 50-Hz 2-mT Electromagnetic Field on Primary Cultured Hippocampal Neurons. med./bio.

Published in: Neurosci Bull 2017; 33 (3): 299-306

Aim of study (acc. to author)

To evaluate the effects of single or repeated exposure to 50 Hz magnetic fields on several biological parameters in hippocampal neurons in vitro.

Background/further details

For single exposure, cells were exposed once for 30 minutes (exposure 1) or 8 hours (exposure 2) after they were cultured for 7 or 14 days (after being removed from rat embyos). For repeated exposure, cells were exposed for 30 min (exposure 3) or 8 hours (exposure 4) every day in the morning starting with the 1. or the 7. day of culture (after being removed from rat embryos). For every exposure condition, a corresponding sham exposure was performed.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: one-time 30 minutes
Exposure 2: 50 Hz
Exposure duration: one-time 8 hours
Exposure 3: 50 Hz
Exposure duration: 30 minutes per day for 7 days (starting with the 1. day in culture) or for 8 days (starting with the 7. day in culture)
Exposure 4: 50 Hz
Exposure duration: 8 hours per day for 7 days (starting with the 1. day in culture) or for 8 days (starting with the 7. day in culture)

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Exposure duration one-time 30 minutes
Exposure setup
Exposure source
Setup apparatus consisted of two identical coil systems placed in a µ-metal box (thickness of 1.3 mm, 25 x 25 x 25 cm3); boxes were laid beside each other in an incubator; each of the two coil systems was composed of four square subcoils (side length 20 cm) arranged symmetrically around the coil center; paired wires formed the coils, coils were connected in parallel for exposure or anti-parallel for sham exposure; two fans were mounted on each box for ventilation; inhomogeneity of magnetic field was <4%.
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 2 mT - - - -

Exposure 2

Main characteristics
Frequency 50 Hz
Type
Exposure duration one-time 8 hours
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 2 mT - - - -

Exposure 3

Main characteristics
Frequency 50 Hz
Type
Exposure duration 30 minutes per day for 7 days (starting with the 1. day in culture) or for 8 days (starting with the 7. day in culture)
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 2 mT - - - -

Exposure 4

Main characteristics
Frequency 50 Hz
Type
Exposure duration 8 hours per day for 7 days (starting with the 1. day in culture) or for 8 days (starting with the 7. day in culture)
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 2 mT - - - -

Reference articles

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

No significant changes were observed between cells exposed one-time to a magnetic field (exposure 1 and 2) and sham exposed cells.
Cells that were repeatedly exposed for 8 hours/day (exposure 4) showed a significantly decreased cell viability compared to the corresponding sham exposed cells while cells that were repeatedly exposed for 30 minutes/day (exposure 3) showed a significantly increased cell viability (when exposure started with the seventh day in culture). The generation of reactive oxygen species was significantly increased in exposure groups 3 and 4 in comparison to the corresponding sham exposure group (when exposure started with the seventh day in culture). Additionally, the protein expression level of NOX2 was significantly increased in exposure group 4 when compared to sham exposed cells.
No significant effects were found on DNA damage, apoptosis or autophagy.
The authors conclude that repeated exposure to a 50 Hz magnetic field could decrease the cell viability via oxidative stress in hippocampal neurons in vitro but seems not to induce severe adverse biological effects.

Study character:

Study funded by

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