Study type: Medical/biological study (experimental study)

Direction-Dependent Effects of Combined Static and ELF Magnetic Fields on Cell Proliferation and Superoxide Radical Production. med./bio.

Published in: Biomed Res Int 2017; 2017: 5675086

Aim of study (acc. to author)

To investigate the effects of exposure to a static magnetic field in combination with horizontal or vertical extremely low frequency magnetic fields on cell proliferation in endothelial cells and on superoxide level in rat glioma cells.

Endpoint

Exposure

Exposure Parameters
Exposure 1:
Exposure duration: not given
Exposure 2:
Exposure duration: not given
Exposure 3: 0–18 Hz
Exposure duration: not given
Exposure 4: 0–18 Hz
Exposure duration: not given
Exposure 5: 0–18 Hz
Exposure duration: not given
Exposure 6:
Exposure duration: not given
near-zero magnetic field
Exposure 7: 50 Hz
Exposure duration: 24 hours
Exposure 8: 50 Hz
Exposure duration: 24 hours

Exposure 1

Main characteristics
Frequency
Type
Exposure duration not given
Additional info endothelial cells
Exposure setup
Exposure source
Chamber cells were exposed in 8 by 12 cm 6-well plates, plates were centered vertically and horizontally between coils; temperature 30°C
Setup triaxial single-wound Helmholtz coils were used to generate uniform static MF and vertical or horizontal 18 Hz magnetic fields, each coil consisted of 20 turns of copper wire, side of each square coil measured 20–25 cm; distance between each pair of coils was 10–12 cm; a function generator was connected directly to the coils
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 60 µT - measured - -

Exposure 2

Main characteristics
Frequency
Type
Exposure duration not given
Additional info endothelial cells
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 120 µT - measured - -

Exposure 3

Main characteristics
Frequency 0–18 Hz
Type
Exposure duration not given
Additional info endothelial cells, combined field DC + AC (18 Hz)
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 60 µT - measured - static magnetic field
magnetic flux density 30 µT effective value measured - vertical 18 Hz magnetic field

Exposure 4

Main characteristics
Frequency 0–18 Hz
Type
Exposure duration not given
Additional info endothelial cells, combined field DC + AC (18 Hz)
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 60 µT - measured - static magnetic field
magnetic flux density 30 µT effective value measured - horizontal 18 Hz magnetic field

Exposure 5

Main characteristics
Frequency 0–18 Hz
Type
Exposure duration not given
Additional info endothelial cells, combined field DC + AC (18 Hz)
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 120 µT - measured - static magnetic field
magnetic flux density 30 µT effective value measured - vertical 18 Hz magnetic field

Exposure 6

Main characteristics
Frequency
Exposure duration not given
Additional info near-zero magnetic field
Additional info endothelial cells
Exposure setup
Exposure source
Setup MF was attenuated by a horizontally rested µ-metal cylinder (radius 12 cm and length 30 cm), cylinder allowed free flow of CO2-air mixture but attenuated the static MF over an 8 cm by 12 cm volume in the middle of the cylinder
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 0.2 µT minimum measured - -
magnetic flux density 2 µT maximum measured - -

Exposure 7

Main characteristics
Frequency 50 Hz
Type
Exposure duration 24 hours
Additional info glioma cells
Exposure setup
Exposure source
Chamber temperature was constant (± 0.1°C)
Setup Helmholtz coils were used to produce the 50 Hz magnetic field; each coil (radius of 10.5 cm) consisted of 5 turns of copper wire with 2 mm diameter; to produce either a vertical or a horizontal field, coil system could be turned; two identical coil systems in two identical incubators were used for simultaneous magnetic field exposure and sham exposure (no current connected for sham exposure)
Sham exposure A sham exposure was conducted.
Additional info geomagnetic field was about 33 µT and almost vertical (inclination 80–85°) in the incubators
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 30 µT - measured - horizontal

Exposure 8

Main characteristics
Frequency 50 Hz
Type
Exposure duration 24 hours
Additional info glioma cells
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 30 µT - measured - vertical

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

In endothelial cells grown under a near-zero magnetic field (exposure 6), cell proliferation was significantly decreased compared to static magnetic fields of 60 and 120 µT (exposure 1 and 2). The vertical 18 Hz magnetic field in combination with the static magnetic field of 60 µT (exposure 3) resulted in a slight, significant increase compared to the static magnetic field alone (exposure 1). However, cell proliferation in cells exposed to a combination of horizontal 18 Hz magnetic field and static magnetic field (exposure 4) was significantly reduced to half of that of static magnetic field alone (exposure 1). A further experiment which compared only the near-zero magnetic field (exposure 6) with the combined horizontal 18 Hz magnetic field and static magnetic field of 60 µT (exposure 4) confirmed that the combined field significantly decreased the cell proliferation.
In rat glioma cells, the cytosolic superoxide level was significantly increased under exposure to the horizontal 50 Hz magnetic field (exposure 7) compared to the sham exposed cells but not under the vertical magnetic field (exposure 8). No effects were observed on cell viability and level of superoxide in mitochondria between sham exposed cells and those exposed to a 50 Hz magnetic field (exposure 7 and 8).
The results indicate that the effects of a static magnetic field on cell proliferation in endothelial cells and superoxide level in rat glioma cells can be disrupted by a weaker extremely low frequency magnetic field depending on the relative direction of the extremely low frequency field.

Study character:

Study funded by

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