Two different chemical agents were used for inducing DNA damage (for 3 h following exposure): menadione as a free radical-producing and methyl methanesulfonate as an alkylating agent. Menadione and methyl methanesulfonate were also used for positive controls (but in higher concentrations).
Exposure duration: continuous for 24 h
Cells were exposed in four groups: i) sham exposure ii) MF exposure iii) sham exposure + chemical treatment iv) pre-exposure to MF + chemical treatment chemical treatment either with menadione or with methyl methanesulfonate
|Setup||pair of 340 mm x 460 mm Helmholtz coils, 220 mm apart, housed inside a temperature-controlled incubator with 5% CO2; cells placed in 55 mm plastic Petri dishes or 48 well plates (micronuclei experiments) in the center of the coil system|
|Sham exposure||A sham exposure was conducted.|
|magnetic flux density||100 µT||-||measured||-||-|
Pre-exposure to the magnetic field enhanced the menadione-induced DNA damage, DNA repair rate (reduced level of DNA damage), and micronucleus formation in human SH-SY5Y neuroblastoma cells. Although the findings with methyl methanesulfonate indicated similar effects, the differences were not statistically significant. No effects were found after magnetic field exposure alone.
The authors conclude that the data confirmed their previous findings (Markkanen et al. 2008) showing that pre-exposure to magnetic fields as low as 100 µT altered cellular responses to menadione, and showed that increased genotoxicity results from such interaction.