Study type: Medical/biological study (experimental study)

Induction of kinetochore-positive and kinetochore-negative micronuclei in CHO cells by ELF magnetic fields and/or X-rays. med./bio.

Published in: Mutagenesis 2003; 18 (5): 439-443

Aim of study (acc. to author)

To test the genotoxic effects of extremely low frequency magnetic fields, the induction of micronuclei by exposure to extremely low frequency magnetic fields and/or X-rays was investigated in cultured CHO cells.

Background/further details

The micronuclei formation was further investigated whether it was kinetochore-positive or negative in order to distinguish between chromosome breakage and errors in chromosome distribution.
The experiment were repeated three times.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 60 Hz
Exposure duration: continuous for 24 h
Exposure 2: 60 Hz
Exposure duration: continuous for 18 h
Exposure 3: 60 Hz
Exposure duration: continuous for 24 h + 18 h

General information

Magnetic field exposure took place either before or after 1 Gy X-ray irradiation at the dose rate of 1.02 Gy/min or without any pre or post X-ray irradiation.

Exposure 1

Main characteristics
Frequency 60 Hz
Type
Waveform
Exposure duration continuous for 24 h
Exposure setup
Exposure source
Chamber 600 silicon steel strips, each 0.5 mm thick making a core. Two copper coils (10 x 20 mm²) penetrate into the silicon steel core. The incubator (inner space 190 x 220 x 28 mm³) was inserted into the inner space of the core. Magnetic field was homogeneous within 1% difference for the area housing four 10 cm or ten 6 cm culture dishes.
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 5 mT unspecified unspecified - -

Exposure 2

Main characteristics
Frequency 60 Hz
Type
Exposure duration continuous for 18 h
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 5 mT unspecified unspecified - -

Exposure 3

Main characteristics
Frequency 60 Hz
Type
Exposure duration continuous for 24 h + 18 h
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 5 mT unspecified unspecified - -

Reference articles

  • Miyakoshi J et al. (1994): A newly designed experimental system for exposure of mammalian cells to extremely low frequency magnetic fields.

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

No statistically significant difference in the frequency of micronuclei in CHO cells was observed between a sham exposure and extremely low frequency magnetic field exposure.
The exposure to an extremely low frequency magnetic field before or after X-ray radiation did not affect the frequency of X-ray-induced micronuclei. However the number of kinetochore-positive micronuclei was significantly increased in the cells subjected to X-ray radiation followed by extremely low frequency magnetic field exposure.
The number of spontaneous kinetochore-positive micronuclei was not affected by exposure to an extremely low frequency magnetic field alone.

Study character:

Study funded by

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