Pregnant mice were divided into 4 groups (n=2 dams per group): 1) only exposure to the magnetic field (n=20 pups), 2) only X-radiation (1 Gy) on day 11.5 post conception (n=25 pups), 3) X-radiation and subsequent exposure to the magnetic field (n=31 pups), 4) sham exposure (n=27 pups).
On day 42 after birth, 43 young animals were sacrificed for sperm and testes examinations and the rest was killed after 140 days (remark EMF-Portal: it is not stated how many animals from each group were sacrificed and possibly more animals were killed in total. Specifications on this are contradictory and the numbers of animals used in each test are not fully comprehensible).
|polycarbonate cages were placed in solenoid (0.8 m in length and 0.13 m in radius, with 552 turns of 2.5 mm2 copper wire, wound in two layers in continuous forward-backward fashion around a cylinder made of PVC; applied voltage was 6.5 V (rms)); the field was uniform between ± 5% in the volume where the mice were exposed; the solenoid was not shielded against the electric field, as the induced electric field was negligible due to the low voltage used; temperature and the relative humidity were 22°C and 40%, respectively
|A sham exposure was conducted.
|control and X-radiation groups were placed in a switched off solenoid
Significanly increased numbers of micronuclei in comparison to the sham exposure group (group 4) were found in groups 2 (X-radiation alone) and 3 ( X-radiation and MF exposure) at several points in time. Only after 42 days, a significantly higher amount of micronuclei compared to the sham exposure group was also observed in group 1 (magnetic field alone).
The mean testes weight was significantly smaller in all exposure groups (groups 1-3) compared to the sham exposure group. Exposure to the magnetic field alone or to X-radiation alone resulted in a significantly reduced amount of post-meiotic haploid spermatids compared to the sham exposure group and to a combination of X-radiation and MF exposure. The mean sperm numbers were significantly reduced in X-radiated mice in comparison to the sham exposure group and to a combination of X-radiation and MF exposure.
In the comet assays, the combination of X-radiation and MF exposure resulted in significantly reduced DNA damage compared to X-radiation alone.
No teratogenic effects were found in any group.
The authors conclude that prenatal and postnatal exposure of mice to a 50 Hz-magnetic field has only a slight genotoxic potential, but it might modulate the effects of prior X-radiation on sperms.