Altogether 214 mice were used. Blood samples were taken from the medial venous plexus of the murine eye. In experiment 1 blood samples were collected from exposed offspring (i.e. exposure began already in utero) 180 and 280 days after birth and in the experiments 3-5 with young male or adult male mice after the exposure, in experiment 2 with adult male rats also before the exposure started.
The following five experiments were done: 1) exposure to 50 Hz from day 1 post conception until day 280 of age 2) exposure to 50 Hz for 140 days from day 84 of age 3) exposure to 50 Hz or 20 kHz for 20 days, 30 days, 40 days or 60 days from day 29 of age 4) exposure to 50 Hz for 1, 2 or 4 days from day 21 of age 5) exposure to 50 Hz for 90 days from day 30 of age
|Exposure duration||continuous 24 h/day for 20, 30, 40 or 60 days|
The first blood sample of exposed offspring in experiment 1 showed significant higher percentage of eosinophilic leukocytes in the 50 Hz magnetic field exposed male CBA/S mice. Exposed female CBA/S mice exhibited a significant decrease in the number of polynuclear cells which was also reflected in the total number of leukocytes. The second blood sample revealed sigificant increase in mononuclear cells and total number of leukocytes in both males and females.
In experiment 2 with adult CBA/Ca mice the mean number of lymphocytes and the ratio of polychromatic to normochromatic erythrocytes decreased significantly in the exposure group.
After 30 days of 50 Hz magnetic field exposure respectively 20 days of 20 kHz magnetic field exposure in experiment 3 the number of mononuclear cells was significantly lower in CBA/S exposed mice than in control animals.
No statistically significant changes in investigated blood cells were found in 50 Hz magnetic field short-term exposed CBA/Ca mice of experiment 4.
Statistically significant increased number of polychromatic erythrocytes and decreased number of micronucleated polychromatic erythrocytes were observed in 50 Hz magnetic field long-term exposed CBA/S mice of experiment 5.
In conclusion, these results indicate no consistent effect of magnetic field exposure on the number of blood cells. As the number of leukocytes are particularly labile a larger number of animals should be investigated. The authors summarize that the investigated magnetic fields do not exert strong effect on leukocyte and erythrocyte formation in mouse bone marrow.