Study type: Medical/biological study (experimental study)

Electromagnetic fields inhibit endothelin-1 production stimulated by thrombin in endothelial cells med./bio.

By: Morimoto S, Takahashi T, Shimizu K, Kanda T, Okaishi K, Okuro M, Murai H, Nishimura Y, Nomura K, Tsuchiya H, Ohashi I, Matsumoto M
Published in: J Int Med Res 2005; 33 (5): 545-554
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Aim of study (acc. to author)

To study the effect of radiofrequency electromagnetic field on basal and thrombin-stimulated endothelin-1 (a potent vasoconstrictor) expression and production in cultured cells from a variety of sources (bovine aortic endothelial cells, human umbilical vascular endothelial cells, human aortic endothelial cells, and human microvascular endothelial cells).

Background/further details

Electromagnetic field exposure has been found to induce arteriolar dilatation, but the mechanism of action remains largely unknown.
To study whether nitric oxide may participate in the mediation of endothelin-1 production by electromagnetic field, a competitive inhibitor of nitric oxide synthase (NG-monomethyl-L-arginine) was used to block the synthesis of nitric oxide in the cell cultures.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 10 MHz
Modulation type: pulsed
Exposure duration: continuous for 8 h or 24 h
Exposure 2: 10 MHz
Modulation type: pulsed
Exposure duration: continuous for 8 h or 24 h
Exposure 3: 10 MHz
Modulation type: pulsed
Exposure duration: continuous for 8 h or 24 h

Exposure 1

Main characteristics
Frequency 10 MHz
Exposure duration continuous for 8 h or 24 h
Modulation
Modulation type pulsed
Duty cycle 50 %
Repetition frequency 10,000 Hz
Exposure setup
Exposure source
  • coil plate consisting of circular loop generator coils
Setup 96 well culture plates containing endothelial cells were placed on a coil plate. Cells were sham exposed for the same duration under the same set-up conditions.
Additional info The distance between the generator coil and the cells was 2.0 mm.
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 1.25 V/m unspecified calibration - -
SAR 0.98 mW/kg unspecified unspecified - -

Exposure 2

Main characteristics
Frequency 10 MHz
Exposure duration continuous for 8 h or 24 h
Modulation
Modulation type pulsed
Duty cycle 50 %
Repetition frequency 10,000 Hz
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
SAR 2.31 mW/kg unspecified unspecified - -
electric field strength 1.92 V/m unspecified calibration - -

Exposure 3

Main characteristics
Frequency 10 MHz
Exposure duration continuous for 8 h or 24 h
Modulation
Modulation type pulsed
Duty cycle 50 %
Repetition frequency 10,000 Hz
Exposure setup
Exposure source
  • coil plate consisting of circular loop generator coils (different diameter)
Setup 100 mm culture dish containing endothelial cells was placed on a coil plate. Cells were sham exposed for the same duration under the same set-up conditions.
Additional info The distance between the generator coil and the cells was 2.3 mm.
Parameters
Measurand Value Type Method Mass Remarks
SAR 8.06 mW/kg unspecified unspecified - -
electric field strength 3.59 V/m unspecified calibration - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

Electromagnetic field exposure reduced endothelin-1 basal levels in human umbilical vein and microvascular endothelial cells, but failed to reduce endothelin-1 basal levels in bovine and human aortic endothelial cells.
Electromagnetic field exposure significantly inhibited thrombin-stimulated (thrombin up-regulates the endothelin-1 production) endothelin-1 production in all four endothelial cell types in a dose-dependent manner.
Electromagnetic field irradiation significantly inhibited thrombin-induced endothelin-1 mRNA expression in all four cell types.
The inhibitory effect on endothelin-1 production was abolished by the nitric oxide synthase inhibitor.
These findings demonstrate that electromagnetic field exposure modulates endothelin-1 production in cultured vascular endothelial cells and the inhibitory effect is, at least partly, mediated through a nitric oxide-related pathway.

Study character:

Study funded by