Study type: Medical/biological study (experimental study)

Extremely low-frequency electromagnetic field exposure enhances inflammatory response and inhibits effect of antioxidant in RAW 264.7 cells. med./bio.

Published in: Bioelectromagnetics 2017; 38 (5): 374-385

Aim of study (acc. to author)

The effects of exposure of macrophages to a 60 Hz magnetic field on the inflammatory and antioxidative response should be investigated.

Background/further details

Cells were stimulated with 0.1, 0.5 or 1 μg/ml LPS and either exposed (group 1) or cultured under "normal" conditions (control group, no details given). Moreover, depending on the investigative technique (see "methods"), cells from both groups were additionally treated with a lentivirus to cause a knockdown (similar to knockout) of the peroxiredoxin gene (weakens the cellular antioxidant response), stimulated with ionomycin (affects cytokine production, dose not mentioned) or were treated with resveratrol (20 µM), an antioxidant.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 60 Hz
Exposure duration: continous for 2 hours - 1 day

Exposure 1

Main characteristics
Frequency 60 Hz
Type
Exposure duration continous for 2 hours - 1 day
Exposure setup
Exposure source
Chamber plates with 24, 48 or 96 wells
Setup the field generator comprised four square coils and one cage with three testing floors (top, middle, and bottom); the magnetic field was produced by one pair of Helmholtz coils with windings embedded in an open wooden rectangular frame; each coil had 200 turns of an insulated soft copper wire with a diameter of 1 mm; each winding was split, allowing the current to flow in the same direction through each half of the winding (field adding); spatial variation of the magnetic field was <3%; the temperature in the incubator was maintained at 37 ± 0.38°C
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 0.8 mT - measured - at the center of the middle floor

Reference articles

  • Lee YJ et al. (2016): Effects of exposure to extremely low-frequency electromagnetic fields on the differentiation of Th17 T cells and regulatory T cells.

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

The production of nitric oxide and iNOS gene expression as well as gene expressions and protein expressions of inflammatory cytokines TNF-alpha, IL-1beta and IL-6 were significantly increased in cells exposed to the magnetic field (group 1) compared to control group cells. Moreover, exposed cells showed a significant activation of NF-kappa B and nuclear factor of activated T cells (NFAT) 2 signal pathways as well as a significantly increased calcium influx compared to control group cells. Cell proliferation and phagocytosis were not affected by the magnetic field.
In cells with a knockdown of the peroxiredoxin or with addition of resveratrol, exposure to the magnetic field was associated with higher inflammatory responses of macrophages compared to control group cells.
The authors conclude that exposure of macrophages to a 60 Hz magnetic field might enhance the inflammatory response and decrease the effectiveness of antioxidants.

Study character:

Study funded by

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