Medical/biological study (experimental study)

Effect of 26 week magnetic field exposures in a DMBA initiation-promotion mammary gland model in Sprague-Dawley rats med./bio.

By: Boorman GA, Anderson LE, Morris JE, Sasser LB, Mann PC, Grumbein SL, Hailey JR, McNally A, Sills RC, Haseman JK

Published in: Carcinogenesis 1999; 20 (5): 899-904

Aim of study (acc. to author)

To investigate the effect of 26 week magnetic field exposures on chemically induced brest cancer in rats.

Background/further details

DMBA (7,12-dimethylbenzanthracene) was used as chemical agent to induce breast cancer. Three sets of experiments were conducted, each including 100 rats (see fields 1-3). A single 10 mg dose of DMBA was administered orally.

Endpoint

cancer: breast cancer

Exposure

Exposure	Parameters
Exposure 1: 50 Hz Exposure duration: 18.5 h/day, 7 days/week, for 26 weeks	magnetic flux density: 100 µT unspecified
Exposure 2: 50 Hz Exposure duration: 18.5 h/day, 7 days/week, for 26 weeks	magnetic flux density: 500 µT unspecified
Exposure 3: 60 Hz Exposure duration: 18.5 h/day, 7 days/week, for 26 weeks	magnetic flux density: 100 µT unspecified

Exposure 1

Main characteristics

Frequency	50 Hz
Type	magnetic field
Waveform	sinusoidal
Exposure duration	18.5 h/day, 7 days/week, for 26 weeks

Exposure setup

Exposure source	coil sets: 4 pairs of horizontal coils, 240mH,
Chamber	3 identical field generating coil sets in single room, 5 rats per polycarbonate cage 23x15x5in,
Setup	once a week cages were rotated on racks

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	100 µT	unspecified	measured	-	-

Additional parameter details

stray field 50 Hz: 5-30 mG, control: < 0,1µT

Exposure 2

Main characteristics

Frequency	50 Hz
Type	magnetic field
Waveform	sinusoidal
Exposure duration	18.5 h/day, 7 days/week, for 26 weeks

Exposure setup

Exposure source	same setup as exposure 1

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	500 µT	unspecified	measured	-	-

Additional parameter details

stray field 50 Hz: 5-30 mG, control: < 0,1µT

Exposure 3

Main characteristics

Frequency	60 Hz
Type	magnetic field
Waveform	sinusoidal
Exposure duration	18.5 h/day, 7 days/week, for 26 weeks

Exposure setup

Exposure source	same setup as exposure 1

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	100 µT	unspecified	measured	-	-

Additional parameter details

stray fields 60Hz: < 0,3µT, control: < 0.1µT

Exposed system:

Methods Endpoint/measurement parameters/methodology

cancer: promotion of breast cancer (palpation, histological evaluation)
body weight, mortality

Investigated system:

investigation on living organism

Investigated organ system:

breast

Time of investigation:

during exposure
after exposure

Main outcome of study (acc. to author)

No effect of magnetic field exposure on tumor size could be found. This study does not support the hypothesis that magnetic field exposure promotes breast cancer in this DMBA rat model

Study character:

medical/biological study
experimental study
full/main study

Study funded by

National Institute of Environmental Health Sciences (NIEHS), North Carolina, USA

Comments on this article

Anderson LE et al. (2000): Effects of 50- or 60-Hertz, 100 µT magnetic field exposure in the DMBA mammary cancer model in Sprague-Dawley rats: possible explanations for different results from two laboratories

Fedrowitz M et al. (2012): Gene expression in the mammary gland tissue of female Fischer 344 and Lewis rats after magnetic field exposure (50 Hz, 100 muT) for 2 weeks
Soffritti M et al. (2010): 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
Fedrowitz M et al. (2008): Exposure of Fischer 344 rats to a weak power frequency magnetic field facilitates mammary tumorigenesis in the DMBA model of breast cancer
Negishi T et al. (2008): Lack of promotion effects of 50 Hz magnetic fields on 7,12-dimethylbenz(a)anthracene-induced malignant lymphoma/lymphatic leukemia in mice
Fedrowitz M et al. (2005): Power frequency magnetic fields increase cell proliferation in the mammary gland of female Fischer 344 rats but not various other rat strains or substrains
Fedrowitz M et al. (2004): Significant differences in the effects of magnetic field exposure on 7,12-dimethylbenz(a)anthracene-induced mammary carcinogenesis in two substrains of Sprague-Dawley rats
McCormick DL et al. (1999): Chronic toxicity/oncogenicity evaluation of 60 Hz (power frequency) magnetic fields in B6C3F1 mice
Anderson LE et al. (1999): Effect of 13 week magnetic field exposures on DMBA-initiated mammary gland carcinomas in female Sprague-Dawley rats
Boorman GA et al. (1999): Chronic toxicity/oncogenicity evaluation of 60 Hz (power frequency) magnetic fields in F344/N rats

Effect of 26 week magnetic field exposures in a DMBA initiation-promotion mammary gland model in Sprague-Dawley rats med./bio.

Aim of study (acc. to author)

Background/further details

Endpoint

Exposure

Exposure 1

Main characteristics

Exposure setup

Parameters

Additional parameter details

Exposure 2

Main characteristics

Exposure setup

Parameters

Additional parameter details

Exposure 3

Main characteristics

Exposure setup

Parameters

Additional parameter details

Methods Endpoint/measurement parameters/methodology

Main outcome of study (acc. to author)

Study funded by

Comments on this article

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