Medical/biological study (experimental study)

Acceleration of mammary tumorigenesis by exposure of 7,12-dimethylbenz[a]anthracene-treated female rats in a 50-Hz, 100-microT magnetic field: replication study med./bio.

By: Mevissen M, Häußler M, Lerchl A, Loscher W

Published in: J Toxicol Environ Health A 1998; 53 (5): 401-418

Aim of study (acc. to author)

To replicate the investigations of a former study (q.v. publication 3419) on the effects of a 50 Hz/100 µT magnetic field exposure on tumor development in DMBA treated rats.

Background/further details

A total of 198 rats were used in this study (divided into two groups/99 animals each). One group was MF exposed, the other one served as sham-exposed control. Each rat recived an initial oral dose of DMBA (5mg) prior exposure or sham exposure. DMBA application was conducted over the next 3 weeks up to a total dose of 20 mg.

Endpoint

cancer: breast tumors

Exposure

Exposure	Parameters
Exposure 1: 50–60 Hz Exposure duration: 24 h/day, 7days/week for 91 days	magnetic flux density: 100 µT effective value

Exposure 1

Main characteristics

Frequency	50–60 Hz
Type	magnetic field
Waveform	sinusoidal
Polarization	linear
Exposure duration	24 h/day, 7days/week for 91 days

Exposure setup

Exposure source	coil(s)
Setup	four 1 m square coils with 26 turns of 1.5 mm² copper wire for the outer coils and 11 turns of the same wire for the inner coils
Sham exposure	A sham exposure was conducted.

Parameters

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

Reference articles

Baum A et al. (1995): A histopathological study on alterations in DMBA-induced mammary carcinogenesis in rats with 50 Hz, 100 muT magnetic field exposure

Exposed system:

Methods Endpoint/measurement parameters/methodology

cancer: development of breast tumors (palpitation in vivo/histological examination in vitro)
melatonin determination (radioimmunoassay), liver and spleen weight
body weight, behavioral alteration

Investigated system:

blood samples (melatonin determination)
investigation on living organism

Investigated organ system:

skin

Time of investigation:

during exposure
after exposure

Main outcome of study (acc. to author)

Melatonin levels were examined after 12 weeks of exposure. No differences between the exposed and sham-exposed could be demonstrated. Furthermore, no behavioral differences or differences in body weight were observed between both groups. Also liver and spleen weight did not differ between groups.
9 weeks after DMBA application, the MF exposed group started to exhibit significantly more animals with tumors than the sham-exposed group. A histopathological examination revealed a even greater difference in tumore incidence between exposed and sham-exposed group.

Study character:

medical/biological study
experimental study
replication/reproduction study

Study funded by

Department of Energy, USA

Replicated studies

Baum A et al. (1995): A histopathological study on alterations in DMBA-induced mammary carcinogenesis in rats with 50 Hz, 100 muT magnetic field exposure

Soffritti M et al. (2016): Life-span exposure to sinusoidal-50 Hz magnetic field and acute low-dose gamma radiation induce carcinogenic effects in Sprague-Dawley rats
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
Baum A et al. (1995): A histopathological study on alterations in DMBA-induced mammary carcinogenesis in rats with 50 Hz, 100 muT magnetic field exposure