Abstract
We investigated the effects of repetitive magnetic stimulation on tumor development processes and immune functions. A circular coil (inner diameter = 15 mm, outer diameter = 75 mm) was used in experiments. The stimulus conditions were as follows: peak magnetic field = 0.25 T (at the center of the coil), frequency = 25 pulses/sec, 1000 pulses/sample/day. Magnetically induced eddy currents in mice = 0.25 T: 0.79−1.54 A/m2. B16-BL6 melanoma model mice were exposed to the magnetic stimulation for 16 days from the day after the injection of cancer cells. Tumor growth study revealed a significant decrease in the tumor weight of the stimulated group (56% vs. a sham group, 41% vs. a controls). B16-BL6 cells were also exposed to the magnetic stimulation (1000 pulses/sample). However, magnetically induced eddy currents had no effect on B16-BL6 cell viabilities. Contrary to the cell viability study, proliferation activities of mice spleen cells were up-regulated by the magnetic stimulation. TNF-α production was also activated in the stimulated mice. These results indicate that the immune functions were up-regulated by the magnetic stimulation, resulting in decreased tumor weight in the tumor model mice. And they also show the potential for therapeutic use of magnetic stimulation in cancer treatment.
