Study type: Medical/biological study (experimental study)

Antagonistic effects of a 50 Hz magnetic field and melatonin in the proliferation and differentiation of hepatocarcinoma cells med./bio.

By: Cid MA, Ubeda A, Hernandez-Bule ML, Martinez MA, Trillo MA
Published in: Cell Physiol Biochem 2012; 30 (6): 1502-1516
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Aim of study (acc. to author)

The effects of exposure of hepatic carcinoma cells to a 50 Hz magnetic field and a treatment with melatonin on cell viability, proliferation and differentiation should be investigated.

Background/further details

Cells were exposed with or without melatonin (10 nM or 1 µM). For each group, a respective sham exposure was conducted. Cells were investigated directly after exposure.
Additionally, cells were treated with melatonin alone (0.01 nM - 1 µM), without exposure to the magnetic field or sham exposure. Cells of these groups were investigated 5 days after plating.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: intermittent exposure (3 h on/3 h off) for 24 hours
Exposure 2: 50 Hz
Exposure duration: intermittent exposure (3 h on/3 h off) for 42 hours
Exposure 3: 50 Hz
Exposure duration: intermittent exposure (3 h on/3 h off) for 90 hours

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Waveform
Polarization
Exposure duration intermittent exposure (3 h on/3 h off) for 24 hours
Modulation
Modulation type cf. additional info
Exposure setup
Exposure source
Chamber 60 mm petri dishes in two identical, magnetically shielded chambers (Co-NETIC metal) located in two identical CO2 incubators
Setup two identical pairs of coils connected in series to produce a vertically polarized and homogeneous magnetic field were placed inside the shielded chambers; each coil was made of 1000 turns of enameled copper wire; petri dishes were placed in the center of the coils; the incubator maintained a 5% CO2 and 100% humidity atmosphere at 37°C
Sham exposure A sham exposure was conducted.
Additional info in each experimental run, only one of the two coil sets was energized for MF exposure and the other one was used for sham exposure; both incubators were used alternatively for MF-exposure or sham exposure, in a random sequence
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 10 µT - measured - -
Additional parameter details

the ambient DC and AC (50 Hz) fields inside the shielded chambers were 0.04 ± 0.03 µT rms and 0.05 ± 0.04 µT rms, respectively

Exposure 2

Main characteristics
Frequency 50 Hz
Type
Waveform
Polarization
Exposure duration intermittent exposure (3 h on/3 h off) for 42 hours
Modulation
Modulation type cf. additional info
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 10 µT - measured - -

Exposure 3

Main characteristics
Frequency 50 Hz
Type
Waveform
Polarization
Exposure duration intermittent exposure (3 h on/3 h off) for 90 hours
Modulation
Modulation type cf. additional info
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 10 µT - measured - -

Reference articles

  • Trillo MA et al. (2012): Influence of a 50 Hz magnetic field and of all-transretinol on the proliferation of human cancer cell lines

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

The cell viability did not show any significant differences between any exposure or melatonin-treated group and the respective sham exposure or control groups.
However, exposure to the magnetic field alone resulted ina significantly increased cell proliferation and a significantly decreased differentiation compared to the sham exposure groups.
A treatment with a very low dose of melatonin (0.01 nM) resulted in a significantly increased cell proliferation as well, higher concentrations (0.2 nM - 1 µM) led to a significantly decreased proliferation and a significantly increased differentiation (10 nM and 1 µM) compared to the control group.
In the co-exposure groups, melatonin (10 nM and 1 µM) led to a significant reduction or even a suppression of the proliferation-promotive effect of the magnetic field exposure. Regarding differentiation, however, only a small dose of melatonin (10 nM) reversed the decreased differentiation effect of the magnetic field exposure. Higher concentrations of melatonin in combination with the magnetic field (1 µM) did not show this antagonistic effect and led instead to the same decreased differentiating effects as found in the magnetic exposure alone.
The authors conclude, that exposure to a 50 Hz magnetic field and a treatment with melatonin might have partially antagonistic effects on cell proliferation and differentiation in hepatic carcinoma cells. As a whole, the results suggest that weak extremely low frequency magnetic fields could influence cancer-related processes in vitro, and reinforce the hypothesis that these fields could interfere with the potentially anti-tumoral action of melatonin.

Study character:

Study funded by

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