Medical/biological study (experimental study)

Magnetic field exposure increases cell proliferation but does not affect melatonin levels in the mammary gland of female Sprague Dawley rats med./bio.

By: Fedrowitz M, Westermann J, Loscher W

Published in: Cancer Res 2002; 62 (5): 1356-1363

Aim of study (acc. to author)

To investigate the effects of 50 Hz /100 µT magnetic field exposure on cell proliferation in mammary epithelium of rats. Furthermore, possible changes in melatonin levels in pineal gland and mammary tissue were investigated. An additional experiment with TPA (tetradecanoylphorbol acetate)-treatment was used for comparison with effects of magnetic field-exposure.

Endpoint

cell viability/cell division/proliferation: cell proliferation
endocrine changes: melatonin levels

Exposure

- 50/60 Hz
- magnetic field
- source not given

Exposure	Parameters
Exposure 1: 50 Hz Exposure duration: 24 h/day, 7 days/week, for 2 weeks	magnetic flux density: 100 µT effective value

Exposure 1

Main characteristics

Frequency	50 Hz
Type	magnetic field
Waveform	sinusoidal
Exposure duration	24 h/day, 7 days/week, for 2 weeks
Additional info	horizontally polarized EMF

Exposure setup

Exposure source	not specified
Sham exposure	A sham exposure was conducted.

Parameters

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

Additional parameter details

sham/stray field: 0,1 µT

Reference articles

Mevissen M et al. (1998): 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
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

cell viability/cell division/proliferation: determination of cell proliferation (BrdU (bromodeoxyuridine) labeling and antibody labeling of nuclear proliferation associated Ki-67 protein)
morphol./histopathol. changes: tissue slices (immunhistological examination)
endocrine changes: melatonin levels in pineal gland and mammary tissue (HPLC and electrochemical detection)

Investigated system:

isolated bio./chem. substance
tissue slices

Investigated organ system:

endocrine system
mammary tissue

Time of investigation:

during exposure
after exposure

Main outcome of study (acc. to author)

Magnetic field exposure did not affect melatonin levels in pineal gland and mammary tissue. However, cell proliferation in mammary tissue was significantly enhanced by magnetic field exposure, as indicated by the used labeling techniques. Bromodeoxyuridine and Ki-67 labeling in mammary tissue was not affected by TPA treatment, but was increased in epithelial cells of the skin, particularly in hair follicles.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

Deutsche Forschungsgemeinschaft (DFG; German Research Foundation)

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
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
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