Study type: Medical/biological study (experimental study)

Low power microwave radiation inhibits the proliferation of rabbit lens epithelial cells by upregulating P27Kip1 expression. med./bio.

Published in: Mol Vis 2004; 10: 138-143

Aim of study (acc. to author)

To study the effects of low power microwave irradiation on the proliferation of cultured rabbit eye lens epithelial cells.

Background/further details

There was less than a 0.6 °C difference between the temperature of the culture medium in the exposed and sham-exposed cells (after 8 h of irradiation).
Cell proliferation through the cell cycle are regulated by the sequential activity of various cyclin-dependent kinases. In addition, cyclin-dependent kinases activity can be negatively regulated by a group of proteins termed cyclin-dependent kinases inhibitors. One family of cyclin-dependent kinases inhibitors includes P21WAF1 and P27Kip1. Overexpression of these inhibitors can attenuate the proliferative response, whereas a reduction in their expression increases proliferation.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 2,450 MHz
Modulation type: CW
Exposure duration: continuous for 8 h
Exposure 2: 2,450 MHz
Modulation type: CW
Exposure duration: continuous for 4, 6, and 8 h

Exposure 1

Main characteristics
Frequency 2,450 MHz
Type
Exposure duration continuous for 8 h
Modulation
Modulation type CW
Exposure setup
Exposure source
  • not specified
Setup Cells were exposed under controlled temperature conditions (25 °C) in 35 mm² culture dishes or in 96-well culture plates.
Sham exposure A sham exposure was conducted.
Additional info Sham exposed cells were treated in the same way as the exposed cells except that the power to the antenna was not activated.
Parameters
Measurand Value Type Method Mass Remarks
power density 0.1 mW/cm² - measured - -
power density 0.25 mW/cm² - measured - -
power density 0.5 mW/cm² - measured - -
power density 1 mW/cm² - measured - -
power density 2 mW/cm² - measured - -

Exposure 2

Main characteristics
Frequency 2,450 MHz
Type
Exposure duration continuous for 4, 6, and 8 h
Modulation
Modulation type CW
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
power density 2 mW/cm² - measured - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

After 8 h of irradiation, cells exposed to 0.50, 1.00, and 2.00 mW/cm² exhibited decreased cell viability, increased cell condensation and an inhibition of DNA synthesis. The cells showed significant G0/G1 arrest in the cell cycle. No obvious changes could be detected in the groups exposed to 0.10 and 0.25 mW/cm² microwave irradiation.
Protein expression of P27Kip1 was markedly increased after exposure. However, the mRNA levels were unchanged. There were no detectable differences in P21WAF1 protein expression and mRNA levels between microwave exposed and control groups.
This study indicates that low power microwave irradiation higher than 0.50 mW/cm² can inhibit eye lens epithelial cell proliferation, and increase the expression of P27Kip1.

Study character:

Study funded by

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