Study type: 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.

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

Exposure

Exposure Parameters
Exposure 1: 50–60 Hz
Exposure duration: 24 h/day, 7days/week for 91 days

Exposure 1

Main characteristics
Frequency 50–60 Hz
Type
Waveform
Polarization
Exposure duration 24 h/day, 7days/week for 91 days
Exposure setup
Exposure source
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

Investigated system:
Investigated organ system:
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:

Study funded by

Replicated studies

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