Study type: Medical/biological study (experimental study)

50-Hz MF does not affect global DNA methylation of SH-SY5Y cells treated with the neurotoxin MPP med./bio.

By: Benassi B, Santangeli S, Merla C, Tarantini L, Bollati V, Butera A, Marino C, Consales C
Published in: Bioelectromagnetics 2019; 40 (1): 33-41
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Aim of study (acc. to author)

The epigenetic effects of exposure of neuroblastoma cells to a 50 Hz magnetic field on global DNA methylation should be investigated.

Background/further details

Exposure to extremely low frequency magnetic fields has been associated with an increased risk of neurodegenerative disorders. The underlying mechanisms, however, are still unclear. Hence, exposure to a magnetic field was tested either alone or in combination with 1-methyl-4-phenylpyridinium (MPP+), a neurotoxin which simulates Parkinson's disease, in either proliferating or differentiated neuroblastoma cells. Accordingly, the following groups were used: 1) exposure of proliferating cells to the magnetic field for 24 h, 2) exposure of differentiated cells to the magnetic field for 24 h, 3) exposure of proliferating cells to the magnetic field for 48 h, 4) exposure of differentiated cells to the magnetic field for 48 h, 5) exposure of proliferating cells to the magnetic field for 72 h, 6) exposure of differentiated cells to the magnetic field for 72 h. Groups 1) and 2) were also tested with a treatment of 0.5 mM MPP+ for 24 h after exposure to the magnetic field. For all exposure groups, respective sham exposures were conducted. For the MPP+ treatment, respective controls were conduted.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: 24, 48 or 72 hours

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Exposure duration 24, 48 or 72 hours
Exposure setup
Exposure source
Chamber cells were placed in 60 mm Petri dishes inside incubators
Setup exposure system consisted of two pairs of square coils in separate incubators, which were used for exposure and sham exposure at the same time; field homogeneity was 95% in the exposure volume; temperature was kept stable at 37.0 ± 0.2°C
Sham exposure A sham exposure was conducted.
Additional info coil double wire configuration was used for sham exposure, which allowed for obtaining a null B-field by using currents flowing in opposite directions
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 1 mT effective value measured - -
Additional parameter details

sham exposures were performed at an ambient magnetic field of about 0.3 µT (RMS), representing the background field emitted by the incubator electronics

Measurement and calculation details

magnetic field measurements were performed at the center of the exposure volume of each couple of coils (20 x 20 x 10 cm3) with an isotropic probe; field homogeneity within the exposure setup and induced electric field values within the culture samples, were numerically determined using a finite element method

Reference articles

  • Consales C et al. (2018): Fifty-Hertz Magnetic Field Affects the Epigenetic Modulation of the miR-34b/c in Neuronal Cells
  • Benassi B et al. (2016): Extremely low frequency magnetic field (ELF-MF) exposure sensitizes SH-SY5Y cells to the pro-Parkinson's disease toxin MPP+

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

Exposure to the magnetic field did not induce significant changes in global DNA methylation in any exposure group, with or without treatment with MPP+, compared to the respective sham exposures.
The authors conclude that exposure of neuroblastoma cells to a 50 Hz magnetic field does not influence global DNA methylation.

Study character:

Study funded by

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