The study is an extension of previous studies (publication 387, publication 10066). Exposure to a 50 Hz sinusoidal magnetic field for 24 h inhibited gap junction intercellular communication in CHL cells at an intensity of 0.4 mT and enhanced the inhibition effect of TPA at 0.2 mT.
Cell were exposed with or without TPA (5 ng/ml).
The experiments were conducted in 8 treatment groups with 4 dishes in each group: 1) sham exposure, 2) 0.4 mT MF alone, 3) 0.4 mT MF + 0.4 mT noise MF, 4) 0.4 mT noise alone, 5) 0.2 mT MF plus TPA (5 ng/ml), 6) same as 5 plus noise MF, 7) 0.2 mT alone, 8) 5 ng/ml TPA alone.
|Setup||Three groups of square coils (36 x 36 cm) placed in a CO2 incubator. The upper, middle and the lower coils were connected in series and spaced 8 cm apart from each other. The coils were placed in an iron metal container with a lot ventilation holes to shield cells from stray MF. A very uniform magnetic field was present in the center (10 x 10 x 10 cm³) of the coils, where the cells were located.|
|Sham exposure||A sham exposure was conducted.|
|Additional info||To generate noise MF, the coils system was double-wrapped with two lines of copper wires. One of the double wires was provided with 30-910 Hz white noise signal and the other was fed with 50 Hz AC current.|
The gap junction intercellular communication of NIH3T3 cells was significantly inhibited by magnetic field exposure. However, there were no significant differences between the sham exposed cells, "magnetic field + noise magnetic field" exposure, and "noise magnetic field exposure", indicating that the superposition of a noise magnetic field alleviated the suppression of gap junction intercellular communication induced by the 50 Hz magnetic field.
In addition, although magnetic field exposure at 0.2 mT synergistically enhanced TPA-induced gap junction intercellular communication inhibition further imposition of a noise magnetic field abolished the synergistic effect of coherent magnetic field.
In conclusion, the present data clearly showed that although noise magnetic field itself had no effect on gap junction intercellular communication of NIH3T3 cells, its superposition onto a coherent sinusoidal magnetic field at the same intensity abolished magnetic field-induced gap junction intercellular communication suppression.