Study type: Medical/biological study (experimental study)

Extremely low-frequency magnetic fields can impair spermatogenesis recovery after reversible testicular damage induced by heat med./bio.

By: Tenorio BM, Ferreira Filho MB, Jimenez GC, de Morais RN, Peixoto CA, Nogueira Rde A, da Silva Junior VA
Published in: Electromagn Biol Med 2014; 33 (2): 139-146
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Aim of study (acc. to author)

To investigate the effects of extremely low frequency magnetic fields on spermatogenesis recovery after testicular degeneration induced by heat in rats.

Background/further details

6 groups of rats were examined (n=6 per group). After a single testicular heat shock (43°C for 12 minutes), rats were exposed or sham exposed to the magnetic field for 15, 30, or 60 days.

Exposure

Exposure Parameters
Exposure 1: 60 Hz
Exposure duration: three daily exposures of 30 minutes for 15, 30, or 60 days

Exposure 1

Main characteristics
Frequency 60 Hz
Type
Waveform
Exposure duration three daily exposures of 30 minutes for 15, 30, or 60 days
Exposure setup
Exposure source
Chamber rats were placed in a cylindrical compartment made of polyvinyl chloride with openings for air intake, centrally located in the Helmholtz coil
Setup pairs of Helmholtz coils; each coil was made of wire copper coated with vinyl, 154 turns, 38 cm diameter and 2.1 Ohm electrical impedance; coils were connected in parallel to a voltage generator, producing a uniform magnetic field; field lines crossed the animals transversely
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 1 mT - measured - ± 0.1 mT
Additional parameter details

induced effective electromotive force on each testis was around 0.21 mV

Reference articles

  • Costa EV et al. (2013): Fractal analysis of extra-embryonic vascularization in Japanese quail embryos exposed to extremely low frequency magnetic fields
  • Tenorio BM et al. (2012): Evaluation of testicular degeneration induced by low-frequency electromagnetic fields

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

Plasma testosterone concentration was not changed by the magnetic field exposure.
After 30 and 60 days of exposure, the weight of the testes was significantly decreased compared to the sham exposure, while the gonadosomatic index was only significantly decreased after 60 days of exposure.
After 15 days of exposure, the decrease in the volume of the seminiferous tubules lumen was the only significantly changed parameter in comparison to the sham exposure. However, after 30 and 60 days several changes regarding the volume of the testes components, the cell ultrastructure and histomorphometrical parameters occurred in the exposure group when compared to the testes of sham exposed rats. Summarized, rats from the sham exposure group had a reestablished and active spermatogenesis 60 days after the heat shock procedure, while exposed animals still showed serious testicular degeneration.
The authors conclude that extremely low frequency magnetic fields could inhibit the spermatogenesis recovery after testicular degeneration induced by heat in rats.

Study character:

Study funded by

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