The administration of menadione for co-exposure was based on previous findings indicating that exposure to magnetic fields alters cellular responses to menadione (Markkanen et al. 2008, Luukkonen et al. 2011). Menadione leads to the prodution of superoxide anions and DNA damage.
Neuroblastoma cells were treated with 0, 1, 5, 10 and 20 µM and glioma cells were treated with 0, 1, 5, 10, 15, 20 and 50 µM menadione and were either not exposed to the magnetic field (control groups), sham exposed or exposed to a 10 or 30 µT magnetic field.
|Chamber||cell culture dishes in coil system in incubator (temperature-controlled and 5% CO2)|
|Setup||horizontal magnetic field was generated by a pair of coils (34 cm x 46 cm) in a Helmholtz-type configuration (22 cm distance between the coils); cell culture dishes were placed at the center of the coil system, where the magnetic field was homogeneous|
|Sham exposure||A sham exposure was conducted.|
|Additional info||control cells were incubated in an identical incubator as exposed and sham exposed cells|
|magnetic flux density||10 µT||-||measured||-||-|
Sham exposure did not show any significant effects in any parameter compared to the control groups in both cell lines.
Micronuclei formation was significantly increased in neuroblastoma cells exposed to the 30 µT magnetic field compared to the control group. It was most pronounced in cells co-exposed to the highest concentration of menadione (20 µM) and a significant interaction of menadione and the magnetic field exposure was detected. That means, that the effect of the magnetic field was dependent on the presence and amount of menadione. In C6 cells, the magnetic field had no significant effect on micronuclei formation compared to the control groups.
Cytosolic and mitochondrial superoxide production were significantly increased only in C6 cells exposed to 10 µT or 30 µT magnetic fields compared to the control groups. No interactions of the magnetic field and menadione were observed.
Cell viability was not affected significantly by the magnetic field or co-exposure to the magnetic field and menadione.
The authors conclude that exposure to a 50 Hz magnetic field might provoke DNA damage in human neuroblastoma cells and oxidative stress in rat glioma cells. In the genotoxic effects, the magnetic field enhanced the effcts of menadione in a co-exposure, while the effects on oxidative stress were independent of co-exposure.