Exposure duration: 24 h/day, 7 days/week for 91 days
Animals were treated in 4 groups: i) application of dimethylbenz[a]anthracene + EMF exposure ii) application of dimethylbenz[a]anthracen, no EMF exposure iii) EMF exposure iv) neither application of dimethylbenz[a]anthracen nor EMF exposure
|magnetic flux density||100 µT||-||measured||-||-|
A total of 216 rats were used in this study, divided into four groups: Group A) 99 animals, DMBA treated, MF exposed. Group B) 99 animals, DMBA treated, MF sham-exposed. Group C) 9 animals, non-DMBA-treated, MF exposed. D) 9 animals, non-DMBA-treated, MF-sham-exposed.
The first DMBA (5mg/rat) application occured prior exposure and was followed by three more applications in a weekly interval up to a total doses of 20 mg/rat.
Histopathological examination was carried out after 91 days of exposure/sham-exposure. MF-exposed, DMBA-treated animals exhibits significantly more macroscopically visible mammary tumors than DMBA-treated sham-exposed controls. Tumor size was significantly larger in MF-exposed rats, too. The number of neoplastic and non-neoplasic lesions did not significantly differ between groups. In MF-exposed groups, significantly more animals exhibit malignant mammary tumors. The data demonstrate that long-term 50 Hz MF exposure of DMBA treated femal rats promotes the growth and progression of mammary tumors, while tumor incidence is not effected.