Study type: Medical/biological study (experimental study)

Calcium signalling in human neutrophil cell lines is not affected by low-frequency electromagnetic fields. med./bio.

Published in: Bioelectromagnetics 2015; 36 (6): 430-443

Aim of study (acc. to author)

The adverse effects of exposure of human neutrophil granulocyte-like cells to a 50 Hz magnetic field or to a combination of several extremely low frequency and intermediate frequency fields on calcium signal pathways should be investigated.

Background/further details

In two different cell lines, HL-60 and PLB-985 cells, a differentiation into neutrophil-like cells was induced by the addition of DMSO. The combination of different low-frequency and intermediate frequency fields was called "Immunent field".
Both cell lines were exposed to two different types of fields (50 Hz and Immunent field) and 4 different magnetic flux densities (2,5 mT, 500 µT, 300 µT, and 5 µT) for 3 minutes, 30 minutes, 4 days or 5 days.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: continuous for 30 minutes
Exposure 2: 50 Hz–2.6 kHz
Exposure duration: continuous for 30 minutes
Immunent field
Exposure 3: 50 Hz
Exposure duration: continuous for 30 minutes, 4 days or 5 days
Exposure 4: 50 Hz–2.6 kHz
Exposure duration: continuous for 30 minutes, 4 days or 5 days
Immunent field
Exposure 5: 50 Hz
Exposure duration: intermittent for a total of up to 3 minutes

General information

background alternating current magnetic flux densities at the place of exposure and sham exposure were less than 0.2 µT and ambient direct current static magnetic fields were 10 µT (except for exposure 5)

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration continuous for 30 minutes
Exposure setup
Exposure source
Chamber cell culture flasks
Setup coil was placed inside a standard cell culture incubator with 37°C ± 0.2°C and 5% CO2; cell culture flasks were placed in the central region of the coils, perpendicular to vertical magnetic field lines; copper wire coil was wound on a double co-axial cylinder with an inner (65 turns; Ø 184 mm) and outer cylinder (2 times 8 turns; Ø 400 mm) made of polymethyl methacrylate; inhomogeneity within exposure area was < 0.4%
Sham exposure A sham exposure was conducted.
Additional info two identical cell culture incubators with identical exposure coil inside were used and randomly assigned to be active or sham for each experiment
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 5 µT - measured - -
electric field strength 1.57 mV/m maximum - - -

Exposure 2

Main characteristics
Frequency 50 Hz–2.6 kHz
Type
Exposure duration continuous for 30 minutes
Additional info Immunent field
Additional info combination of four block waves at frequencies of 320, 730, 880 and 2600 Hz
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 5 µT - measured - -
electric field strength 0.3 V/m maximum - - -

Exposure 3

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration continuous for 30 minutes, 4 days or 5 days
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 500 µT - measured - -
electric field strength 1.57 mV/m maximum - - -

Exposure 4

Main characteristics
Frequency 50 Hz–2.6 kHz
Type
Exposure duration continuous for 30 minutes, 4 days or 5 days
Additional info Immunent field
Additional info combination of four block waves at frequencies of 320, 730, 880 and 2600 Hz
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 300 µT - measured - -
electric field strength 0.3 V/m maximum - - -

Exposure 5

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration intermittent for a total of up to 3 minutes
Additional info for flow cytometry
Exposure setup
Exposure source
Chamber test tubes
Setup custom-made exposure system fitting around the test tube inside the flow cytometer; the circular coil consisted of 0.5 mm tightly wound copper wire around a polyether ether ketone body with an inner diameter of 38 mm (100 turns); the direction of the field was parallel to the height of the test tube
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 2.5 mT - measured - -
electric field strength 1.57 mV/m maximum - - -

Reference articles

  • Bouwens M et al. (2012): Low-frequency electromagnetic fields do not alter responses of inflammatory genes and proteins in human monocytes and immune cell lines.
  • de Kleijn S et al. (2011): Extremely low frequency electromagnetic field exposure does not modulate toll-like receptor signaling in human peripheral blood mononuclear cells.

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

No significant differences could be found between the exposure groups and their corresponding sham exposure groups.
The authors conclude that exposure of human neutrophil granulocyte-like cells to a 50 Hz magnetic field or to a combination of several extremely low frequency and intermediate frequency fields has no effect on calcium signal pathways.

Study character:

Study funded by

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