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.
|Exposure duration||24, 48 or 72 hours|
|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|
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.