Study type: Medical/biological study (experimental study)

Complex effects of long-term 50 Hz magnetic field exposure in vivo on immune functions in female Sprague-Dawley rats depend on duration of exposure med./bio.

By: Mevissen M, Häußler M, Szamel M, Emmendorffer A, Thun-Battersby S, Loscher W
Published in: Bioelectromagnetics 1998; 19 (4): 259-270
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Aim of study (acc. to author)

To investigate the effects of a in vivo 50 Hz/100 µT magnetic field exposure on rat lymphocytes.

Background/further details

Femal rats were continuously exposed to a magnetic field (50 Hz/ 100 µT) up to 13 weeks. After 2, 4, 8, and 13 weeks splenic lymphocytes were cultured to assess proliferation capacity of T- and B-lymphocytes, and interleukin 1 production. For this purpose lymphocytes were mitogen activated, concanavalin A and pokeweed mitogen were used for T- and B-lymphocytes, respectively.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: continuous for 2 weeks.
Exposure 2: 50 Hz
Exposure duration: continuous for 4 weeks.
Exposure 3: 50 Hz
Exposure duration: continuous for 8 weeks.
Exposure 4: 50 Hz
Exposure duration: continuous for 13 weeks.

General information

Merritt et al.(1983)

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration continuous for 2 weeks.
Exposure setup
Exposure source
Chamber Trovidur exposure chambers placed on wooden posts in an exposure room/ 7.32 m x 4.52 m.
Setup Four acrylic cages each 39 cm x 55 cm x 22 cm per exposure chamber with seperate wooden posts placed inside the coil system
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 100 µT effective value measured unspecified -
Additional parameter details

Stray MF in the exposure chamber calculated to be 0.1 µT and in the sham chamber to be 0.03-0.04 µT. Geomagnet field had a parallel component of 16 µT and perpendicular component of 36 µT.

Exposure 2

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration continuous for 4 weeks.
Exposure setup
Exposure source
Chamber Trovidur exposure chambers placed on wooden posts in an exposure room/ 7.32 m x 4.52 m.
Setup Four acrylic cages each 39 cm x 55 cm x 22 cm per exposure chamber with seperate wooden posts placed inside the coil system
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 100 µT effective value measured unspecified -
Additional parameter details

Stray MF in the exposure chamber calculated to be 0.1 µT and in the sham chamber to be 0.03-0.04 µT. Geomagnet field had a parallel component of 16 µT and perpendicular component of 36 µT.

Exposure 3

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration continuous for 8 weeks.
Exposure setup
Exposure source
Chamber Trovidur exposure chambers placed on wooden posts in an exposure room/ 7.32 m x 4.52 m.
Setup Four acrylic cages each 39 cm x 55 cm x 22 cm per exposure chamber with seperate wooden posts placed inside the coil system
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 100 µT effective value measured unspecified -
Additional parameter details

Stray MF in the exposure chamber calculated to be 0.1 µT and in the sham chamber to be 0.03-0.04 µT. Geomagnet field had a parallel component of 16 µT and perpendicular component of 36 µT.

Exposure 4

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration continuous for 13 weeks.
Exposure setup
Exposure source
Chamber Trovidur exposure chambers placed on wooden posts in an exposure room/ 7.32 m x 4.52 m.
Setup Four acrylic cages each 39 cm x 55 cm x 22 cm per exposure chamber with seperate wooden posts placed inside the coil system
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 100 µT effective value measured unspecified -
Additional parameter details

Stray MF in the exposure chamber calculated to be 0.1 µT and in the sham chamber to be 0.03-0.04 µT. Geomagnet field had a parallel component of 16 µT and perpendicular component of 36 µT.

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:
  • after exposure

Main outcome of study (acc. to author)

The mitogenic responsiveness of B-lymphocytes as well as interleukin 1 production was not altered due to magnetic field exposure. However, T-lymphocytes exhibited a triphasic alteration during MF-exposure. Two weeks of MF-exposure leads to markedly enhanced mitogenic responsiveness, after 4 weeks less increased, after 8 weeks no differences to controls were observed, and after 13 weeks the mitogenic resposiveness was significantly decreased.

Study character:

Study funded by

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