Study type: Medical/biological study (experimental study)

Extremely low frequency electromagnetic field exposure affects fertilization outcome in swine animal model. med./bio.

Published in: Theriogenology 2010; 73 (9): 1293-1305

Aim of study (acc. to author)

To study the effect of acute (1h) exposure of boar spermatozoa to a 50 Hz extremely low frequency electromagnetic field on early fertility outcome.

Background/further details

Firstly, in vitro experiments were carried out to define the dosimetric morpho-functional influence of an acute (1 h) exposure to extremely low frequency electromagnetic field on boar spermatozoa with intensities ranging from 0 to 2 mT (at 0.25 mT of interval). Then, using the intensities identified under these in vitro conditions (minimum vs. maximum vs. median toxic dose [TD50]), in vivo experiments were performed by exposing the oviduct with (protocol A) or without spermatozoa (protocol B: capacitated spermatozoa were inserted at the end of field exposure) to extremely low frequency electromagnetic field and by evaluating the outcome of fertilization (12 h later) and the success of the early stage of embryo development (6 days later).
No exact numbers of exposed animals/oviducts or of investigated embryos are stated in the article.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: continuous 1 h
Exposure 2: 50 Hz
Exposure duration: continuous 1 h

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration continuous 1 h
Additional info in vitro
Exposure setup
Exposure source
Setup 30 cm long solenoid with an inner diameter of 12.5 cm, constructed from 8 turns/cm of copper wire on a PVC cylinder; samples placed on a coronal Plexigls plane in the central area of the solenoid inside a humified incubator
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 0 mT minimum - - raised in steps of 0.25 mT
magnetic flux density 2 mT maximum - - -

Exposure 2

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration continuous 1 h
Additional info in vivo
Additional info experiment 1: EMF exposure after artifical insemination experiment 2: EMF before surgical insemination
Exposure setup
Exposure source
Setup 11 cm long PVC plane, 4 cm wide and 1 cm thick was surrounded by 144 copper wire spires (0.5 mm diameter); one oviduct inserted into the coil
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 0 mT minimum - - raised in steps of 0.25 mT
magnetic flux density 2 mT maximum - - -

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 data showed that in vitro extremely low frequency electromagnetic field (> 0.5 mT) induced a progressive acrosome damage, thus compromising the ability of spermatozoa to undergo acrosomal reaction after zona pellucida stimulation and reducing the in vitro fertilization outcome. These effects became evident at 0.75 mT (22% damaged) and reached a plateau at 1 mT (30% damaged).
On the contrary, the exposure of spermatozoa to extremely low frequency electromagnetic field (all intensities) did not affect the DNA integrity,
Under in vivo conditions, the extremely low frequency electromagnetic field of intensity of 1 mT significantly reduced the fertilization rate. A decreased fertilization rate was found in absence of spermatozoa at exposure application (protocol B; 80% versus 95% in controls) that resulted more evident when the oviducts were exposed in presence of spermatozoa (protocol A; 68% versus 80% in controls). On the contrary, the polyspermy rate was unaffected in both protocols.
In addition, the exposure of oviducts (≥ 0.75 mT) in the absence of spermatozoa was able to negatively affect early embryo development (a slowdown in the embryo cleavage was found).
In conclusion, it was demonstrated how and at which intensities the extremely low frequency electromagnetic field negatively affect early fertility outcome in a highly predictive animal model.

Study character:

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