Puromycin is an antibiotic, which unselectively inhibits protein biosynthesis in cells, finally causing cell death.
Cells were divided into the follwoing groups: 1) only exposure to a 2 mT static magnetic field, or to a 2) 6 mT static magnetic field, 3) only exposure to an alternating 12 Hz magnetic field, 4) 25 Hz magnetic field, 5) 35 Hz magnetic field, or 6) 50 Hz magnetic field, 7) only puromycin treatment (100 µg/ml), 8) sham exposure. Moreover, several combinations of a static magnetic field, an alternating magnetic field and/or puromycin were tested.
At least 6 experiments were conducted for each measurement.
|Exposure 3: 12 Hz|
|Exposure 4: 25 Hz|
|Exposure 5: 35 Hz|
|Exposure 6: 50 Hz|
in case of a co-exposure to a static field and an alternating field, the alternating field was perpendicularly oriented towards the static field; the background static magnetic field was < 0.05 ± 0.01 mT and the background alternating magnetic field was < 0.03 ± 0.01 mT
|magnetic flux density||2 mT||-||measured||-||-|
|magnetic flux density||6 mT||-||measured||-||-|
Exposure to either a static (groups 1 and 2), an alternating magnetic field (groups 3 - 6) or co-exposure to any combination of both types of magnetic fields had no influence on the cell viability in comparison to the sham exposure.
Exposure to puromycin alone decreased cell viability distinctly compared to the sham exposure. No synergistic effect was observed for a co-exposure to any combination of puromycin and a static or alternating magnetic field.
However, a triple co-exposure to a static and an alternating magnetic field together with puromycin, led to a significant decrease in cell viability compared to the puromycin exposure alone, with the most profound effect in the combination of a triple exposure of cells to a static field with 6 mT, an alternating field with 35 Hz and puromycin.
The authors conclude that co-exposure of U937 cells to a static field and an alternating extremely low frequency field might enhance the cytotoxic effects of puromycin.