The scratch assay is a simple test to measure cell migration. In this assay, a thin "wound" is introduced into a surface with a dense cell growth by scratching with a pipette tip. Cells on the wound edge subsequently migrate into the wound space until the wound is closed. The scratch assay was performed either during a continuous exposure of up to 65 h or under the conditions of an exposure which was canceled after 24 hours.
All experiments were repeated at least twice.
|Exposure duration||continuous for up to 65 h|
|Chamber||cells were exposed in plates with wells|
|Setup||six well plates were exposed simultaneously; cells were in close contact above antenna in H-field maximum; temperature, humidity and SAR were controlled during exposure; cells were maintained under a humidified atmosphere of 5% CO2 and 95% air at 37°C|
|Sham exposure||A sham exposure was conducted.|
Neither cell viability nor cell proliferation, cell cycle distribution or apoptosis were significantly changed in exposed cells compared to the sham exposure.
The wound healing rate was significantly reduced in exposed cells from 6 to 54 hours and finally, exposed cells needed 65 hours for a complete restoration of the cell layer in comparison to 48 hours in sham exposed cells. In the approach with an exposure solely during the first 24 hours, the healing rate was significantly lower in exposed cultures from 3 to 48 hours compared to the sham exposure. Finally, exposed cells needed 55 hours and sham exposure 48 hours for a complete healing of the scratch. However, the healing rate of cells in this approach was significantly higher from 36 to 48 hours than in the continuously exposed cells.
The authors conclude that an in vitro exposure of human bronchial epithelial cells to a 1.8 GHz electromagnetic field could reduce the wound healing capacity in cell cultures due to an impaired cell migration.