Study type: Medical/biological study (experimental study)

Effect of extremely low-frequency electromagnetic fields on antioxidant activity in the human keratinocyte cell line NCTC 2544 med./bio.

By: Calcabrini C, Mancini U, De Bellis R, Diaz AR, Martinelli M, Cucchiarini L, Sestili P, Stocchi V, Potenza L
Published in: Biotechnol Appl Biochem 2017; 64 (3): 415-422
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Aim of study (acc. to author)

The effects of exposure of human keratinocytes to a 50 Hz magnetic field on cell viability, oxidative stress and the antioxidative defense system should be investigated.

Background/further details

The study was conducted to examine possible cellular damage from the usage of magnetic fields in skin wound healing.
Cells were divided into 6 groups: exposure to a magnetic field of 1) 0.025 mT, 2) 0.05 mT, 3) 0.1 mT, 4) 0.15 mT, 5) 0.2 mT and 6) sham exposure. In two approaches, 3 µM phenanthroline or 2 µM rotenone were added 30 min before 1 hour of exposure in group 2. Phenanthroline is an iron chelator which prevents the Fenton reaction in the cells, while rotenone is an inhibitor of the mitochondrial respiratory chain.
Cells were either investigated directly after exposure or 24 hours later. Positive control was performed.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: continuous for 1 hour
Exposure 2: 50 Hz
Exposure duration: continuous for 1 h, 2 h or 4 hours
Exposure 3: 50 Hz
Exposure duration: continuous for 1 h, 2 h or 4 hours
Exposure 4: 50 Hz
Exposure duration: continuous for 1 hour
Exposure 5: 50 Hz
Exposure duration: continuous for 1 hour

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Exposure duration continuous for 1 hour
Exposure setup
Exposure source
Setup the system consisted of three parallel copper plates (40 x 40 cm) and 4 rectangular containers filled with circulating distilled water to regulate temperature (maintained at 37 ± 0.3°C); Faraday shields excluded electric noise in the units
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 0.025 mT - measured - -
Additional parameter details

the uniformity of the field was kept within 5% of the mean value; magnetic flux density in sham exposure was 0.01 mT

Exposure 2

Main characteristics
Frequency 50 Hz
Type
Exposure duration continuous for 1 h, 2 h or 4 hours
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 0.05 mT - measured - -

Exposure 3

Main characteristics
Frequency 50 Hz
Type
Exposure duration continuous for 1 h, 2 h or 4 hours
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 0.1 mT - measured - -

Exposure 4

Main characteristics
Frequency 50 Hz
Type
Exposure duration continuous for 1 hour
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 0.15 mT - measured - -

Exposure 5

Main characteristics
Frequency 50 Hz
Type
Exposure duration continuous for 1 hour
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 0.2 mT - measured - -

Reference articles

  • Potenza L et al. (2012): Effect of 300 mT static and 50 Hz 0.1 mT extremely low frequency magnetic fields on Tuber borchii mycelium
  • Miller DL et al. (1989): Addition of magnetic field capability to existing extremely-low-frequency electric field exposure systems

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

Only exposure to a 0.05 mT (group 2) and 0.1 mT (group 3) magnetic field for 1 or 2 hours (but not 4 hours) resulted in significantly increased oxidative stress compared to sham exposed cells. Hence, further parameters were only investigated in these groups.
In group 2, phenanthroline reversed the oxidative stress effect while rotenone did not show any effect.
Lipid peroxidation was significantly increased in group 2 after 1 hour, while the amount of reduced glutathione and enzyme activities of glutathione reductase and superoxide dismutase were significantly decreased compared to the sham exposure group. The effects attenuated over time and after 24 hours, there were no significant differences between exposed and sham exposed cells found anymore. Group 3 showed a significantly reduced superoxide dismutase enzyme activity after 1 hour and a significantly increased amount of reduced glutathione after 4 hours of exposure compared to the sham exposure group.
Cell viability was not influenced significantly by exposure to a magnetic field in any group.
The authors conclude that exposure of human keratinocytes to a 50 Hz magnetic field might induce slight oxidative stress that does not overwhelm the antioxidative capacity of the cells and can be compensated without showing a cytotoxic effect.

Study character:

Study funded by

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