Study type: Medical/biological study (experimental study)

Superimposition of an Incoherent Magnetic Field Eliminated the Inhibition of Hormone Secretion Induced by a 50-Hz Magnetic Field in Human Villous Trophoblasts in vitro. med./bio.

Published in: Cell Physiol Biochem 2010; 26 (4-5): 793-798

Aim of study (acc. to author)

To study the possible mechanism of extremely low frequency in relation to adverse pregnancy outcomes, the effect of a 50 Hz magnetic field exposure on secretion of human chorionic gonadotropin and progesterone in cultured human first trimester villous trophoblasts in vitro was investigated. Additionally, it was investigated whether an incoherent magnetic field could interfere the effects of a 50 Hz magnetic field.

Background/further details

Trophoblasts are one of the main components of placenta and play a crucial role in normal pregnancy. They secrete the hormones human chorionic gonadotropin and progesterone. Dysfunction of trophoblasts usually leads to spontaneous abortion.
Placentas were obtained immediately after artificial abortion from healthy nonsmoking women undergoing elective pregnancy termination at 8-10 weeks gestation.
Cells were exposed to a 50 Hz sinusoidal magnetic field, an incoherent magnetic field ("noise" magnetic field) or a combined magnetic field (superimposition of "noise" and 50 Hz sinusoidal magnetic fields) for 6, 12, 24, 48, or 72 hours.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: continuous for 6 h, 12 h, 24 h, 48 h or 72 h
Exposure 2: 30–90 Hz
Exposure duration: continuous for 6 h, 12 h, 24 h, 48 h or 72 h
Exposure 3: 30–90 Hz
Exposure duration: continuous for 6 h, 12 h, 24 h, 48 h or 72 h

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration continuous for 6 h, 12 h, 24 h, 48 h or 72 h
Exposure setup
Exposure source
Setup three groups of 36 cm x 36 cm square copper coils placed in a metal iron container inside an incubator; upper and lower coils consisting of 168 turns, middle coil with 60 turns; coils connected in series and positioned 8 cm apart from each other; culture dishes placed in a 10 cm x 10 cm x 10 cm exposure area inside the coil system where the magnetic field was uniform
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 0.4 mT effective value measured - -

Exposure 2

Main characteristics
Frequency 30–90 Hz
Type
Waveform
Exposure duration continuous for 6 h, 12 h, 24 h, 48 h or 72 h
Exposure setup
Exposure source
Setup three groups of 36 cm x 36 cm square copper coils which were double wrapped in two lines of copper wire placed inside an incubator; only one coil used in this experiment
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 0.4 mT effective value measured - -

Exposure 3

Main characteristics
Frequency 30–90 Hz
Type
Waveform
Exposure duration continuous for 6 h, 12 h, 24 h, 48 h or 72 h
Additional info combination of 50 Hz sinusoidal and 30 Hz - 90 Hz incoherent signal
Exposure setup
Exposure source
Setup three groups of 36 cm x 36 cm square copper coils which were double wrapped in two lines of copper wire placed inside an incubator; one coil used for the incoherent voltage input, the other for the sinusoidal power input
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 0.4 mT effective value measured - -

Reference articles

  • Sun W et al. (2008): An incoherent magnetic field inhibited EGF receptor clustering and phosphorylation induced by a 50-Hz magnetic field in cultured FL cells.

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

The data showed that exposure of the villous trophoblasts to a 50 Hz magnetic field at 0.4 mT for 72 hours could significantly inhibit the secretion of human chorionic gonadotropin and progesterone (no significant effect up to 48 hours), whereas exposure to an incoherent magnetic field (30-90 Hz) did not significantly affect the secretion. However, when the incoherent magnetic field was superimposed on the 50 Hz magnetic field and the cells were exposed to both fields simultaneously, no significant change in hormone secretion was observed.
Based on these results, the authors conclude that 50 Hz magnetic field exposure for 72 hours could inhibit the hormone secretion of trophoblasts, and an incoherent magnetic field of equal intensity could completely eliminate the effects induced by the 50 Hz magnetic field. Although the detailed mechanisms need to be investigated further, the data support the "temporal and spatial coherence hypothesis" (it states that living cells distinguish thermal noise fields from external electromagnetic fields because thermal noise fields are temporally and spatially incoherent whereas an external electromagnetic field is coherent). The hypothesis may provide a new approach to prevent the possible deleterious effects of extremely low frequency electromagnetic fields exposure.

Study character:

Study funded by

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