The cell viability was assessed by cell proliferation, cell cycle progression, expression studies of genes involved in cell proliferation and apoptosis (egr-1, p53, apoptosis inhibitor: bcl-2, survivin) up to chrarcterization of molecular processes via enzyme activity. The investigated transcription factor egr-1 is a gene essential for cell proliferation, cell differentiation, and apoptosis. Increased egr-1 expression and the induced Egr-1 protein is a strong transcriptional activator of key genes involved in cell death pathway.
Lovisolo GA, Asta D, Ciammetti L, Mancini S, Marino C, Pinto R, D'Inzeo G. 2000. In vitro exposure system operating at 900 and 1800 MHz. In: Kostarakis P, Stavroulakis P, editors. Proceeding of Millennium International Workshop on Biological Effects of Electromagnetic field. Heraklion, Crete, Greece, 17-20 October, pp 169-175.
|Exposure duration||continuous for 5, 15, 30 min, 6 or 24 h|
|Chamber||The RF exposure system was based on a wire patch cell (WPC) antenna [Laval et al., 2000] and assembled as described in [Lovisolo et al., 2000]. Two WPCs were located in the same incubator for blinded RF and sham exposure. The absence of any interference between the two WPCs was experimentally confirmed.|
|Sham exposure||A sham exposure was conducted.|
|Additional info||Sixteen hours prior to RF exposure, cells in logarithmic growth were aliquoted from a single parental flask into individual 35-mm Petri dishes. The temperature of the dishes was maintained at 37 ± 1 °C by an appropriate cooling system [Ardoino et al., 2004]. The exposure system was turned on at least 30 min before the experiment, and the temperature in the incubator was monitored with a thermocouple probe (sensitivity ± 0.1 °C) during the exposure.|
The exposure to radiofrequency field for 24 hours exerted a significant reduction in cell viability and cell proliferation. Within exposure the egr-1- gene expression increased in 5 minutes, reaching maximum after 15 minutes, and decline to baseline levels after 6 hours. The enzyme activities of the MAPK subtypes showed similar pattern.
Cells exposed for 24 hours exhibited cell cycle progress typical for apoptosis accompanied by significant decreased gene expression of the investigated apoptosis inhibitor bcl-2 and survivin.