To study whether radiofrequency fields can cause changes in gene expression in cultured human cells. The authors aimed to provide genome-wide coverage of the expressed genes regardless their functional categories in the radiofrequency treated cells to address if radiofrequency has biological effects.
|Exposure duration||continuous for 2 or 6 h|
|Pulse width||155 µs|
|Duty cycle||7.5 %|
|Chamber||The waveguide was filled with a 5% air-CO2 mixture through a hole in its top surface. The bottom of the waveguide was maintained at 37 °C by temperature-controlled water circulating in direct contact with the brass surface through an exterior plastic channel glued to it.|
|Setup||A 25-ml culture flask containing 10 ml of cell suspension was placed inside the waveguide. The bottom of the flask was ground flat and coated with mineral oil to obtain good thermal conduction. The temperature in the bottom surface of the flask monitored by two Luxtron probes was maintained at 37.2 ± 0.2 °C.|
|Sham exposure||A sham exposure was conducted.|
|Additional info||The cells were allowed to settle down to the bottom of the flask to form a monolayer before exposure. Sham exposure was performed in an identical waveguide for 2 h only.|
The authors revealed that 221 genes altered their expression after a 2 h exposure. The number of affected genes increased to 759 after a 6 h exposure. Functional classification of the affected genes showed that apoptosis-related genes were among the upregulated ones and the cell cycle genes among the downregulated ones. No significant increase in the expression of heat shock protein genes was found.
These data suggest that the radiofrequency fields at 2.45 GHz can alter gene expression in cultured human cells through non-thermal mechanism.