Study type: Medical/biological study (experimental study)

Effect of superposed electromagnetic noise on DNA damage of lens epithelial cells induced by microwave radiation. (RETRACTED by publisher) retracted

Published in: Invest Ophthalmol Vis Sci 2008; 49 (5): 2009-2015

Aim of study (acc. to author)

To study the influence of the 1.8 GHz radiofrequency fields (GSM) on DNA damage, intracellular reactive oxygen species formation, cell cycle, and apoptosis in human eye lens epithelial cells and whether the effects induced by radiofrequency could be blocked by superposing of electromagnetic noise (2 µT).

Endpoint

Exposure

Exposure Parameters
Exposure 1: 1.8 GHz
Modulation type: pulsed
Exposure duration: intermittent, 5 min on/10 min off, for 24 h
Exposure 2: 30–90 Hz
Exposure duration: intermittent, 5 min on/10 min off, for 24 h

General information

The cells were subjected to one of four exposure conditions: sham, RF irradiation (4 levels), noise MF, and RF irradiation superposed with noise MF.

Exposure 1

Main characteristics
Frequency 1.8 GHz
Type
Charakteristic
  • guided field
Exposure duration intermittent, 5 min on/10 min off, for 24 h
Modulation
Modulation type pulsed
Duty cycle 12.5 %
Repetition frequency 217 Hz
Pulse type rectangular
Additional info

GSM signal

Exposure setup
Exposure source
Chamber Two waveguides, one for RF and one for sham exposure, were placed inside a conventional incubator at 37°C with 95% air and 5% CO2.
Setup Six 35-mm Petri dishes with cells in a total volume of 2 ml were placed inside the waveguide in a dish holder holding them exactly in the H-field maximum of the standing wave and were exposed simultaneously in E polarization.
Sham exposure A sham exposure was conducted.
Additional info The exposure system has been described in detail by the designer and other groups [Schönborn et al., 2001 and Diem et al., 2005]. It enabled the exposure of a monolayer of cells with less than 30% nonuniformity of SAR.
Parameters
Measurand Value Type Method Mass Remarks
SAR 1 W/kg mean - - -
SAR 2 W/kg mean - - -
SAR 3 W/kg mean - - -
SAR 4 W/kg mean - - -

Exposure 2

Main characteristics
Frequency 30–90 Hz
Type
Exposure duration intermittent, 5 min on/10 min off, for 24 h
Additional info white noise signal
Exposure setup
Exposure source
Chamber To generate a noise MF, both sides of the waveguides were wrapped with two rectangular Helmholtz coils at a center distance of 24 cm.
Additional info The direction of the coils was the same as the circular wires in the RF waveguides, and the direction of the noise MF was consistent with the magnetic field of the RF radiation.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 2 µT - - - "Amplitude"

Reference articles

  • Diem E et al. (2005): Non-thermal DNA breakage by mobile-phone radiation (1800 MHz) in human fibroblasts and in transformed GFSH-R17 rat granulosa cells in vitro.
  • Schönborn F et al. (2001): Basis for optimization of in vitro exposure apparatus for health hazard evaluations of mobile communications.

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

DNA damage was significantly increased after 3 W/kg and 4 W/kg irradiation, whereas the double-strand breaks were significantly increased only after 4 W/kg exposure. Significantly elevated intracellular reactive oxygen species levels were also detected in the 3 W/kg and 4 W/kg groups. After exposure to 4 W/kg for 24 hours, the cells exhibited significant G0 phase/G1 phase cell-cycle arrest. There was no detectable difference in apoptosis between the exposure and sham exposure groups.
All the effects mentioned were blocked when the radiofrequency signal was superposed with 2 µT electromagnetic noise.
In conclusion, microwave exposure induced DNA damage after G0 phase/G1 phase cell-cycle arrest did not lead to apoptosis. The increased reactive oxygen species formation observed may be associated with DNA damage. Superposed electromagnetic noise blocks microwave induced DNA damage, reactive oxygen species formation, and cell cycle arrest.

Study character:

Study funded by

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