Study type: Medical/biological study (experimental study)

Epidermal ornithine decarboxylase and polyamines in mice exposed to 50 Hz magnetic fields and UV radiation. med./bio.

Published in: Bioelectromagnetics 1998; 19 (6): 388-391

Aim of study (acc. to author)

The effects of an acute and chronic exposure of mice to a 50 Hz magnetic field on the epidermal level of polyamines and ornithine decarboxylase enzyme activity should be investigated.

Background/further details

The level of polyamines is increased in cancerous tissues and ornithine decarboxylase generates polyamines, so these parameters were used as markers for skin tumorigenesis. Tumor data of the same study was published elsewhere (Kumlin et al. 1998).
Transgenic K2 mice, which show a 30-50 fold higher ornithine decarboxylase enzyme activity compared to wild type mice, were used together with wild type mice.
For acute exposure experiments, the following groups with wild type and transgenic mice each were used (n=6 each): 1) exposure to UV radiation, 2) exposure to the magnetic field, 3) sham exposure. For chronic exposure experiments, further groups with wild type and transgenic mice each were used (n=10 each): 4) exposure to UV radiation, 5) exposure to UV radiation and continuous magnetic field , 6) exposure to UV and intermittent magnetic field and 7) sham exposure.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: continuous for 24 h
Exposure 2: 50 Hz
Exposure duration: continuous for 10.5 months
continous chronic exposure
  • not stated
Exposure 3: 50 Hz
Exposure duration: intermittend for 10.5 months
intermittend chronic exposure with various MF intensities

General information

UV exposure groups received a single dose of 400 J/m² during acute exposure (group 1) and 200 J/m² for 35 min three times per week, respectively, during chronic exposure conditions (groups 4-6)

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Exposure duration continuous for 24 h
Additional info acute exposure
Exposure setup
Exposure source
  • not specified
Chamber polycarbonate cages
Setup temperature and relative humidity were 23 ± 1°C and 50 ± 15%, respectively
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 100 µT - - - -

Exposure 2

Main characteristics
Frequency 50 Hz
Type
Exposure duration continuous for 10.5 months
Additional info continous chronic exposure
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Additional info 50 Hz MF exposure of the sham-exposed group was less than 0.05 µT
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density - - - - not stated

Exposure 3

Main characteristics
Frequency 50 Hz
Type
Exposure duration intermittend for 10.5 months
Additional info intermittend chronic exposure with various MF intensities
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 1.3 µT minimum - - -
magnetic flux density 13 µT - - - -
magnetic flux density 130 µT maximum - - -

Reference articles

  • Kumlin T et al. (1998): Effects of 50 Hz magnetic fields on UV-induced skin tumourigenesis in ODC-transgenic and non-transgenic mice.

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

In the acute exposure, a significant increase of the putrescine and spermidine levels was observed in transgenic mice exposed to the magnetic field (group 2) compared to sham exposed mice. In the same group, a significant decrease of the ornithine decarboxylase enzyme activity was spotted in transgenic mice compared to sham exposed mice. In wild type mice, no significant differences were found between the groups.
In wild type mice chronically exposed to UV radiation (group 4), a significant increase of the spermidine and spermine levels and a significant decrease of the putrescine level was observed compared to sham exposed mice. In transgenic mice, no significant differences were found between the groups. Moreover, no significant differences were found between groups co-exposed to UV radiation and a magnetic field (groups 5 and 6) and exposure to UV radiation alone.
The authors conclude that an acute exposure of mice to a 50 Hz magnetic field could affect the epidermal level of polyamines and ornithine decarboxylase enzyme activity and thus augment tumorigenesis.

Study character:

Study funded by

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