Study type: Medical/biological study (experimental study)

Exposure of Fischer 344 rats to a weak power frequency magnetic field facilitates mammary tumorigenesis in the DMBA model of breast cancer. med./bio.

Published in: Carcinogenesis 2008; 29 (1): 186-193

Aim of study (acc. to author)

Based on recent data (publication 13141) on magnetic field-induced increase in cell proliferation in the mammary gland, the hypothesis was tested if magnetic field exposure would significantly facilitate development and growth of mammary tumors in Fischer 344 rats (for comparison, some experiments were also performed with Sprague-Dawley and Lewis rats).

Background/further details

108 rats were exposed and 108 rats were sham exposed (9 rats per cage). Each rat received an administration of 10 mg DMBA (corresponding to about 90 mg/kg body weight).

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: continuous for 24h/day (except time for weighing, cleaning, etc.) on 7 days/week for 26 weeks

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Exposure duration continuous for 24h/day (except time for weighing, cleaning, etc.) on 7 days/week for 26 weeks
Exposure setup
Exposure source
  • see reference article
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)

Magnetic field exposure significantly facilitated mammary tumorigenesis: Compared to sham exposed controls, the incidence of histologically verified mammary gland tumors in female Fischer 344 rats after 26 weeks of magnetic field exposure was significantly increased by 31%. The incidence of grossly recorded, histologically verified adenocarcinoma was increased by 45%.
These data indicate that Fischer 344 rats are a suitable inbred strain to study the mechanisms underlying the effects of magnetic field exposure on mammary tumorigenesis.

Study character:

Study funded by

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