The following modified DNA bases generated by free radicals were investigated: 8-hydroxy-guanine (8-OH-Gua); 2,6-diamino-4-hydroxy-5-formamido-pyrimidine (FapyGua) and 4,6-diamino-5-formamido-pyrimidine (FapyAde).
13 rats were randomly divided into four groups: two experimental groups (n=3 and n=4), a sham exposed group and a cage control. In the experiments a 50 Hz exposure by 100 µT and 500 µT was chosen, because these are the limit values set for public and occupational exposure by ICNIRP.
|Exposure duration||continuous for 2 h/day for 10 months|
|Setup||Pair of Helmholtz coils with a diameter of 25 cm, consisting of 225 turns of 1.0 mm insulated copper wire wound on frames of wood and aluminum; coils 25 cm apart, placed horizontally inside a 130 cm x 65 cm x 80 cm Faraday cage; rats kept in 17 cm x 17 cm x 25 cm methacrylate cages inside the coil system|
|Sham exposure||A sham exposure was conducted.|
Levels of FapyAde, FapyGua and 8-OH-Gua in DNA were increased by both 100 µT and 500 µT extremely low frequency magnetic field as compared to cage control and sham exposure group. Statistical significance was observed only in the group exposed to 100 µT.
This is the first study to report that exposure to extremely low frequency magnetic field generated oxidatively induced DNA base modifications in vivo. The findings support the hypothesis that chronic exposure to 50 Hz magnetic fields may be potentially genotoxic.