Study type: Medical/biological study (experimental study)

Mega-experiments on the carcinogenicity of Extremely Low Frequency Magnetic Fields (ELFMF) on Sprague-Dawley rats exposed from fetal life until spontaneous death: plan of the project and early results on mammary carcinogenesis. med./bio.

Published in: Non-thermal effects and mechanisms of interaction between electromagnetic fields and living matter Mattioli 1885, 2010: 219-234, ISBN 9788862611664

Aim of study (acc. to author)

In 2002 the Ramazzini Institute (Italy) lunched an experimental research project to evaluate the potential carcinogenic effects of power frequency magnetic fields in rats exposed from prenatal life until spontaneous death to sinusoidal 50 Hz magnetic fields at various intensity levels, or in association with other agents. For this objective, different experiments were planned.
In the current report, the design of the global project and the first results are shown concerning the carcinogenic effects of 50 Hz magnetic fields and low dose gamma radiation on the mammary gland in female rats (in the EMF-Portal extraction only the experimental data concerning the cocarcinogenic effects are shown).

Background/further details

In the whole mega-expeirment 2100 parental rats and 7133 offspring were included.
In the current experiment 2181 rats (1086 males, 1095 female) were exposed in five groups: 1000 µT exposure + gamma radiation (delivered at 6 weeks of age; n=222), 2) 20 µT exposure + gamma radiation (n=212), 3) 1000 µT exposure alone (n=523), 4) gamma radiation alone (n=223), 5) control group (n=1001). Exposure began during fetal life (12th day of pregnancy) and after weaning, the parental rats were sacrificed. Exposure of offspring lasted until natural death.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: continuous for 19 h/day from day 12 of fetal life (pregnancy) until spontaneous death of offspring

General information

rats were treated in five groups: i) 1000 µT EMF exposure + 10 rads gamma radiation at the age of 6 weeks ii) 20 µT EMF exposure + 10 rads gamma radiation at the age of 6 weeks iii) 1000 µT EMF exposure iv) 10 rads gamma radiation at the age of 6 weeks v) control group (sham exposure)

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Waveform
Polarization
Exposure duration continuous for 19 h/day from day 12 of fetal life (pregnancy) until spontaneous death of offspring
Exposure setup
Exposure source
Setup toroidal shaped exposure device consisting of 24 coils, each made of three turns of insulated copper cable wound on an aluminum superstructure composed of two insulated parts; wooden support structure for allocation of the rat cages placed inside the exposure system; 5 rats per 41 cm x 25 cm x 15 cm polycarbonate cage with a cover of non-magnetic metal; 500 rats per exposure system
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 20 µT - measured - -
magnetic flux density 1,000 µT - measured - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • during exposure
  • after exposure

Main outcome of study (acc. to author)

Co-exposure to both magnetic field and gamma radiation increased the incidence of mammary lumps and also accelerated the onset of such lesions when compared to animals exposed to gamma radiation only, to the 1000 µT magnetic field alone or compared to the control group. Not all lumps palpated were confirmed as being mammary gland lesions, and small lesions may have been missed during clincial controls.
As shown by necropsy data, an increased, but not significant incidence of animals bearing fibroadenomas was observed in females exposed to "1000 µT magnetic field plus gamma radiation" as compared to the other groups. Additionally, exposure to "1000 µT magnetic field plus gamma radiation" caused a significant increase in the incidence of mammary adenocarcinoma.
The authors conclude, that these data show for the first time that a life-span exposure starting from prenatal life to power frequency 50 Hz magnetic field, combined with exposure to a well-known carcinogenic agent (gamma radiation) induce a significant increased risk of malignant tumors (mammary cancer) in female rats.

Study character:

Study funded by

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