Study type: Medical/biological study (experimental study)

Influence of static and alternating magnetic fields on U937 cell viability. med./bio.

Published in: Folia Med Cracov 2014; 54 (4): 21-33

Aim of study (acc. to author)

The effects of (co-)exposure of U937 cells to a static magnetic field, an alternating extremely low frequency magnetic field and/or puromycin on the cell viability should be investigated.

Background/further details

Puromycin is an antibiotic, which unselectively inhibits protein biosynthesis in cells, finally causing cell death.
Cells were divided into the follwoing groups: 1) only exposure to a 2 mT static magnetic field, or to a 2) 6 mT static magnetic field, 3) only exposure to an alternating 12 Hz magnetic field, 4) 25 Hz magnetic field, 5) 35 Hz magnetic field, or 6) 50 Hz magnetic field, 7) only puromycin treatment (100 µg/ml), 8) sham exposure. Moreover, several combinations of a static magnetic field, an alternating magnetic field and/or puromycin were tested.
At least 6 experiments were conducted for each measurement.

Endpoint

Exposure

Exposure Parameters
Exposure 1:
Exposure duration: continuous for 2.5 h or intermittent 3 times for 2.5 h, respectively, at intervals of 24 h
Exposure 2:
Exposure duration: continuous for 2.5 h or intermittent 3 times for 2.5 h, respectively, at intervals of 24 h
Exposure 3: 12 Hz
Exposure duration: continuous for 2.5 h or intermittent 3 times for 2.5 h, respectively, at intervals of 24 h
Exposure 4: 25 Hz
Exposure duration: continuous for 2.5 h or intermittent 3 times for 2.5 h, respectively, at intervals of 24 h
Exposure 5: 35 Hz
Exposure duration: continuous for 2.5 h or intermittent 3 times for 2.5 h, respectively, at intervals of 24 h
Exposure 6: 50 Hz
Exposure duration: continuous for 2.5 h or intermittent 3 times for 2.5 h, respectively, at intervals of 24 h

General information

in case of a co-exposure to a static field and an alternating field, the alternating field was perpendicularly oriented towards the static field; the background static magnetic field was < 0.05 ± 0.01 mT and the background alternating magnetic field was < 0.03 ± 0.01 mT

Exposure 1

Main characteristics
Frequency
Type
Exposure duration continuous for 2.5 h or intermittent 3 times for 2.5 h, respectively, at intervals of 24 h
Exposure setup
Exposure source
Chamber tubes
Setup coils with samples were placed in incubator; magnetic field was homogeneous in test tubes with a accuracy of a few percent; temperature inside the coils was kept at 37 ± 0.1°C
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 2 mT - measured - -

Exposure 2

Main characteristics
Frequency
Type
Exposure duration continuous for 2.5 h or intermittent 3 times for 2.5 h, respectively, at intervals of 24 h
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 6 mT - measured - -

Exposure 3

Main characteristics
Frequency 12 Hz
Type
Waveform
Exposure duration continuous for 2.5 h or intermittent 3 times for 2.5 h, respectively, at intervals of 24 h
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 6.5 mT effective value measured - -

Exposure 4

Main characteristics
Frequency 25 Hz
Type
Waveform
Exposure duration continuous for 2.5 h or intermittent 3 times for 2.5 h, respectively, at intervals of 24 h
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 6.5 mT effective value measured - -

Exposure 5

Main characteristics
Frequency 35 Hz
Type
Waveform
Exposure duration continuous for 2.5 h or intermittent 3 times for 2.5 h, respectively, at intervals of 24 h
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 6.5 mT effective value measured - -

Exposure 6

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration continuous for 2.5 h or intermittent 3 times for 2.5 h, respectively, at intervals of 24 h
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 6.5 mT effective value measured - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

Exposure to either a static (groups 1 and 2), an alternating magnetic field (groups 3 - 6) or co-exposure to any combination of both types of magnetic fields had no influence on the cell viability in comparison to the sham exposure.
Exposure to puromycin alone decreased cell viability distinctly compared to the sham exposure. No synergistic effect was observed for a co-exposure to any combination of puromycin and a static or alternating magnetic field.
However, a triple co-exposure to a static and an alternating magnetic field together with puromycin, led to a significant decrease in cell viability compared to the puromycin exposure alone, with the most profound effect in the combination of a triple exposure of cells to a static field with 6 mT, an alternating field with 35 Hz and puromycin.
The authors conclude that co-exposure of U937 cells to a static field and an alternating extremely low frequency field might enhance the cytotoxic effects of puromycin.

Study character:

Study funded by

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