Two experiments were performed. First, the cell growth was measured after different time points: 1.) 24 hours sham exposure, 2.) 24 hours exposure, 3.) 48 hours sham exposure and 4.) 24 hours exposure, following 24 hours sham exposure.
Secondly, protein expression and enzyme activity were examined after A) 24 hours of sham exposure, B) 24 hours exposure or C) 24 hours exposure following 24 hours sham exposure.
|Exposure duration||continuous 24 or 48 hours|
|Setup||each coil was made of 30 turns, medium radius being 14 cm and the distance between the coils was 17 cm; flasks containing the cell culture were positioned parallel to the symmetry axis of the coils (vertical axis)|
|Sham exposure||A sham exposure was conducted.|
|Additional info||for the sham exposure, Helmholtz coils identical to the active ones were used; however, the current flowed for 15 turns in one direction, and for another 15 turns in the opposite direction|
In the first experiment, the cell growth of the 24 hours-exposed group (group 2) was significantly reduced in comparison to the other groups. No significant differences were observed between group 3 (48 hours sham exposure) and group 4 (24 hours exposure + 24 hours sham exposure).
In the second experiment, the enzyme activity and the protein expression of pseudocholinesterase were significantly increased in the 24 hours-exposed group (group B) compared to the other groups. Additionally, the protein expression of HSP70 was significantly increased in the 24 hours-exposed group (group B) in comparison to the other groups. No significant differences were seen between group A (24 hours sham exposure) and group C (24 hours exposure + 24 hours sham exposure). No significant changes for the enzyme activities of catalase and glutathione peroxidase were observed between the groups.
The authors conclude that exposure to an extremely low frequency electromagnetic field could affect the cell growth, the enzyme activity and protein expression of pseudolcholinesterase and the protein expression of HSP70 in the slime mold Dictyostelium discoideum and that these effects were transient.