Tetradecanoylphorbol acetate (TPA) inhibits gap junctional intercellular communication and was used as a positive control. Moreover, a synergistic effect of co-exposure to magnetic fields and TPA is described in literature (see Li CM et al. (1999) and Hu GL et al. (2001)), what should be examined in the present study.
Cells were divided into the following groups: 1) exposure to a 0.4 mT magnetic field, 2) exposure to a 1 mT magnetic field, 3) co-exposure to a 1 mT magnetic field and 20 ng/ml TPA, 4) positive controls and 5) sham exposure. TPA was added one hour before analysis, respectively.
Each experiment was repeated at least three times.
|Setup||petri dishes were placed in the center of a custom made vertical cylindrical coil (7.6 cm height, 9.2 cm inner diameter, 12.3 cm outer diameter; 854 turns of enameled copper wiring, 1.2 mm diameter, 14 nested layers with 61 turns per layer) inside an incubator; field was constant within 1.7% in the area of the cells; temperature was maintained at 37.0 ± 0.18°C and CO2 at 5% in the incubator and temperature in dishes was 37.0 ± 0.1°C|
|Sham exposure||A sham exposure was conducted.|
|magnetic flux density||0.4 mT||-||measured||-||-|
No significant differences were found in the gap junctional intercellular communication between cells exposed to a magnetic field (groups 1 and 2) and the sham exposure group. Moreover, no significant differences were found between cells co-exposed to the magnetic field and TPA (group 3) and cells exposed to TPA only (positive control).
The authors conclude that the results give no indications for an effect of exposure of mouse fibroblasts to a 50 Hz magnetic field alone or for an synergistic effect with TPA on the gap junctional intercellular communication.