Apoptosis was analysed and the expression of proteins involved in chaperone-mediated auto-phagocytosis (cellfunction, that allows protein degradation in the lysosomes, increases under stress conditions) as well as the level of alpha-synuclein (substrate for chaperone-mediated autophagy).
Four types of controls were performed:
1.) controls reproducing exposition-induced temperature elevation at 37.5 °C
2.) heat shock for 30 minutes at 45 °C
3.) negative control (DMSO) and positive control (staurosporin) for apoptosis
4.) positive control for chaperone-mediated auto-phagocytosis (serum deprivation)
|Exposure duration||continuous for 24 h|
|Pulse width||0.577 ms|
|Repetition frequency||217 Hz|
|Setup||wire-patch cell placed in a chamber with RF-absorbing walls made of ferrite plates; two identical chambers positioned in an incubator one for exposure and one for sham exposure; eight 35 mm petri dishes placed inside a wire-patch cell|
|Sham exposure||A sham exposure was conducted.|
The exposure to GSM-900 MHz failed to induce apoptotic cell death.
The level of Hsc70 was significantly increased after exposure to GSM-900 MHz in comparison to sham exposure, while the level of Hsp90 was significantly decreased, but also in the control group 1 (temperature rise to 37.5 °C). The levels of Lamp-2A, Hsp70 and Hsp40 remained unaltered.
Additionally, the level of alpha-synuclein was significantly decreased after exposure in comparison to sham exposed cells, but also in the control group 1.
The authors suggest that the observed changes in protein expression are most likely linked to temperature rise.