Study type: Medical/biological study (experimental study)

Exposure of cultured astroglial and microglial brain cells to 900 MHz microwave radiation. med./bio.

Published in: Radiat Res 2006; 166 (2): 409-421

Aim of study (acc. to author)

To assess whether 900 MHz irradiation could affect rat astroglial and the microglial cells in culture by studying markers for damage-related processes in the cells.

Background/further details

Astroglial (astrocytes) and microglial cells, two types of glial cells in the brain are interesting in the context of biological effects from microwave exposure.
The release of the two pro-inflammatory cytokines interleukin 6 and tumor necrosis factor-alpha was investigated. Levels of the astroglial cell-specific reactive marker glial fibrillary acidic protein and the microglial reactivity marker ED-1 (a macrophage activation antigen) were also measured.
Positive controls were performed in increased temperatures.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 906.6 MHz
Modulation type: pulsed
Exposure duration: continuous for 4, 8, and 24 h
  • power: 2.8 W average over time
  • power: 23 W peak value
  • SAR: 3.1 W/kg average over time (± 0.2 W/kg)
  • SAR: 25 W/kg peak value
Exposure 2: 906.6 MHz
Modulation type: CW
Exposure duration: continuous for 4 or 24 h

Exposure 1

Main characteristics
Frequency 906.6 MHz
Type
Charakteristic
  • guided field
Exposure duration continuous for 4, 8, and 24 h
Modulation
Modulation type pulsed
Duty cycle 12.5 %
Repetition frequency 217 Hz
Additional info

GSM modulated, one slot

Exposure setup
Exposure source
Chamber short-circuited aluminium waveguide cavity with adjustable end plate operating in TE103 mode
Setup Cells in seven 35-mm Petri dishes were positioned in a ring which was placed in a Plexiglas box located inside the cavity. An extra center dish containing medium but no cells was added to obtain a more homogeneous SAR distribution. Petri dishes were located in the H-field maximum of the standing wave.
Sham exposure A sham exposure was conducted.
Additional info The temperature in the cell culture dishes was maintained at 37 ± 0.2°C by thermostat-controlled cooling water flowing between two glass plates below the dishes. To prevent evaporation of the culture medium, the bottom of the tissue dish holder was filled with a thin layer of deionised water with tensides added which was found not to affect the characteristics of the chamber and also improved the thermal contact between the dishes and the bottom glass plate of the cooling system.
Parameters
Measurand Value Type Method Mass Remarks
power 2.8 W average over time measured - -
power 23 W peak value measured - -
SAR 3.1 W/kg average over time measured and calculated - ± 0.2 W/kg
SAR 25 W/kg peak value - - -

Exposure 2

Main characteristics
Frequency 906.6 MHz
Type
Charakteristic
  • guided field
Exposure duration continuous for 4 or 24 h
Modulation
Modulation type CW
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
SAR 27 W/kg mean measured and calculated - ± 2 W/kg
SAR 54 W/kg mean measured and calculated - ± 3 W/kg

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

No significant differences could be found for any of the parameters studied at any time and for any of the exposure characteristics. Thus the data do not provide evidence for any effect of the microwave irradiation used on damage-related factors in glial cells in vitro.

Study character:

Study funded by

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