H2O2 is an important intracellular compound and can cause cell death through both apoptosis and necrosis. Cells were treated with H2O2 (25, 50, 85 and 100 µM) with or without exposure to the magnetic fields.
Exposure duration: continuous for 24 h
Simultaneous treatment with exposure to the magnetic field and H2O2 (85 or 100 µM) for 24 h increased the number of apoptotic and necrotic cells significantly, and significantly decreased the number of viable cells compared with cells treated with H2O2 alone. The protein levels of Bax and Bcl-2 showed no differences between H2O2-treated cells and those treated with both H2O2 and the magnetic field. Irradiation to the magnetic field also had no effect on H2O2-induced caspase-3 activation. However, the protein levels of active caspase-7 in cells simultaneously exposed to the magnetic field and H2O2 for 2 and 8 h was higher than that of H2O2 treatment alone. In addition, simultaneous exposure to the magnetic field and H2O2 caused PARP cleavage and induced early inactivation at 2 h. H2O2 treatment alone did not produce this effect until 4 h.
The results suggest that although the magnetic field itself cannot induce apoptosis and necrosis, it exerts a promoting effect on H2O2-induced cell death. It demonstrates that caspase-7 as well as PARP might be involved in this process.