Cells were subjected to the following conditions: 1.) X-radiation (5 Gy at a dose rate of 1.2 Gy/min), 2.) heat shock (41°C for 30 minutes), 3.) magnetic field, 4.) X-radiation + heat shock, 5.) magnetic field + heat shock, 6.) X-radiation + magnetic field and 7.) control group.
Exposure duration: continuous for 30 min.
|magnetic flux density||60 µT||-||measured||-||± 0.2 µT|
While X-rays and heat shock significantly influenced the cell proliferation and the cell cycle distribution compared to the control group these parameters were not significantly altered in cell cultures exposed to magnetic fields. A combination of magnetic field exposure and heat shock attenuated the heat shock induced effects. However, no such preventing effect was observed in the combination of X-rays and magnetic fields.
Treatment with heat shock, alone and in combination with X-rays and magnetic fields, led to significantly increased protein expression levels of HSP27, HSP70, HSP75 and HSP78 in comparison to the control cell cultures, while the exposure to magnetic fields alone only significantly increased the protein expression of HSP70.
The authors conclude that extremely low frequency magnetic fields can alter the protein expression level of HSP70 in a human leukemia cell line, but have no influence on cell proliferation and cell cycle. Furthermore, a protective effect of the magnetic fields was observed in heat shocked but not in X-radiated cells.