Study type: Medical/biological study (experimental study)

ELF Alternating Magnetic Field Decreases Reproduction by DNA Damage Induction. med./bio.

Published in: Cell Biochem Biophys 2013; 67 (2): 703-716

Aim of study (acc. to author)

To study the effect of extremely low frequency magnetic fields on the reproduction of the fly Drosophila melanogaster.

Background/further details

Newly eclosed insects were separated into 12 identical groups of ten males and ten females and exposed (at 3 different intensities) or sham exposed continuously during the first 5 days of their adult lives. For the first 48 hours male and female flies were put in different glass vials. After the 48 h, when both males and females of each group were sexually mature, they were put together (10 pairs) in another glass vial and they were allowed to mate and lay eggs for the next 72 h. After these 5 days, the flies were removed from the vials. The female flies were dissected and ovaries studied for DNA damage. The vials with the developing embryos were incubated in the culture room for 6 additional days without exposure.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: continuous for 5 days
Exposure 2: 50 Hz
Exposure duration: continuous for 5 days
Exposure 3: 50 Hz
Exposure duration: continuous for 5 days

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration continuous for 5 days
Exposure setup
Exposure source
Chamber glass tubes with flys were put in the centre of the air cores of the coils, suspended by nylon strings
Setup two nearly identical cylindrical coils were used; both coils had a length of 0.25 m, a radius of 7.5 x 10-2 m and a diameter of insulated wire of 2 x 10-3 m; number of turns in each coil = 330; in the first coil, the turns were parallel and in the same direction, thus generating a magnetic field; in the second coil, half of the turns were antiparallel (parallel but in opposite direction), so that the magnetic field (and the magnetically induced electric field) in a region of about 12 cm width around the centre of the coil was zero (used for sham exposure)
Sham exposure A sham exposure was conducted.
Additional info after it was checked by preliminary experiments that the sequence (mutual position) of the two coils did not affect the outcome of the experiments, their positions were always the same during all experiments, at a certain place of the laboratory with the minimum stray 50-Hz fields and in at least 2 m distance between each other so that the fields of the "exposure coil" did not affect the "sham exposure coil"
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 2.1 mT - measured and calculated - in the centre of the air core
electric field strength 2.72 V/m - calculated - induced electric field (remark EMF-Portal: seems to be the induced eddy current in the fly?)
cf. remarks - - - - electric current in the coil = 1.48 A

Exposure 2

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration continuous for 5 days
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 1.1 mT - measured and calculated - in the centre of the air core
electric field strength 1.43 V/m - calculated - induced electric field (remark EMF-Portal: seems to be the induced eddy current in the fly?)
cf. remarks - - - - electric current in the coil = 0.77 A

Exposure 3

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration continuous for 5 days
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 0.1 mT - measured and calculated - in the centre of the air core
electric field strength 0.13 V/m - calculated - induced electric field (remark EMF-Portal: seems to be the induced eddy current in the fly?)
cf. remarks - - - - electric current in the coil = 0.07 A

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

In the exposed groups, the number of F1 pupae was decreased in comparison to the sham exposed group. The stronger the field intensity the less pupae were counted. However, this effects was only statistically significant with magnetic flux densities of 1.1 and 2.1 mT.
In the ovaries, DNA fragmentation due to apoptotic cell death was found in all exposure groups, but not in the sham exposure group. This effect increased and became more statistically significant with higher field intensities.
The authors conclude that exposure to a 50 Hz-magnetic field could decrease insect reproduction by DNA damage.

Study character:

Study funded by

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