Effects of pulsed magnetic stimulation on tumor development and immune functions in mice

Abstract

We investigated the effects of pulsed magnetic stimulation on tumor development processes and immune functions in mice. A circular coil (inner diameter = 15 mm, outer diameter = 75 mm) was used in the experiments. Stimulus conditions were pulse width = 238 micros, peak magnetic field = 0.25 T (at the center of the coil), frequency = 25 pulses/s, 1,000 pulses/sample/day and magnetically induced eddy currents in mice = 0.79-1.54 A/m(2). In an animal study, B16-BL6 melanoma model mice were exposed to the pulsed magnetic stimulation for 16 days from the day of injection of cancer cells. A tumor growth study revealed a significant tumor weight decrease in the stimulated group (54% of the sham group). In a cellular study, B16-BL6 cells were also exposed to the magnetic field (1,000 pulses/sample, and eddy currents at the bottom of the dish = 2.36-2.90 A/m(2)); however, the magnetically induced eddy currents had no effect on cell viabilities. Cytokine production in mouse spleens was measured to analyze the immunomodulatory effect after the pulsed magnetic stimulation. tumor necrosis factor (TNF-alpha) production in mouse spleens was significantly activated after the exposure of the stimulus condition described above. These results showed the first evidence of the anti-tumor effect and immunomodulatory effects brought about by the application of repetitive magnetic stimulation and also suggested the possible relationship between anti-tumor effects and the increase of TNF-alpha levels caused by pulsed magnetic stimulation.

Biological Effects of Electromagnetic Fields and Recently Updated Safety Guidelines for Strong Static Magnetic Fields

“…Electrical stimulation is well known to cause changes in the local pH and/or temperature, which can lead to cell death. 37,38 However, the eddy currents generated in our study induced change in neither pH nor temperature (2.66×10 -10 9 C/ pulse). 37 We also tested the eŠects of IM and MS on IM-resistant BCR/ABL (＋) cells to examine what cellular mechanisms were involved.…”

“…22,23 Our group has demonstrated the enhanced killing e‹ciency of imatinib mesylate (IM, Gleevec } , Novartis, East Hanover, NJ, USA) in human breakpoint cluster region-abelson (BCR/ABL) (＋) leukemia cells when the cells were subsequently exposed to MS. 34 BCR/ABL is a chimeric gene, generated by the Philadelphia (Ph) chromosome translocation, t(9;22)(q34;q11), 35 and IM was developed as a potent and speciˆc inhibitor of the BCR/ABL tyrosine kinase. 36,37 Figure 3 shows the system used to expose cells to MS; the stimulus conditions tested were 25 pulses/s and 0.1T (1000 pulses/day), 0.25T (1000 or 6000 pulses/day), or 0.5T (1000 pulses/ day). Using theˆnite method, 38 we calculated the magnetic ‰ux as 0.11 to 0.18T and eddy current as 26.8 to 38.1 A/m 2 as in the culture medium for 0.25T (Fig.…”

Beneficial Effects of Electromagnetic Radiation in Cancer

“…There is data supporting the opinion that the use of EMFs has effects in the cell proliferation and in malignant tumours in animals (Tofani et al, 2001;Yamaguchi et al, 2006). It has also been reported that EMFs could act synergistically with chemotherapeutic agents (Gray et al, 2000;Ruiz Gómez et al, 2002), and reverse the resistance of cancer cells in chemotherapy (Hirata et al, 2001;Janigro et al, 2006).…”

“…Exposure of mice in pulsed magnetic fields lasted 16 days. The experimental data showed anticancer and immunomodulatory properties of pulsed magnetic stimulation such as decrease of tumour growth and elevated production of tumour necrosis factor (TNF-a) in mouse spleens (Yamaguchi et al, 2006). In addition, extremely low-frequency pulsed-gradient magnetic field (with the maximum intensity of 0.6-2.0 T, gradient of 10-100 T/m, pulse width of 20-200 ms and frequency of 0.16-1.34 Hz) presented antitumour and antiangiogenic properties, in exposed Kunming mice bearing murine tumour (Zhang et al, 2002).…”

“…Yamaguchi et al explanation and bibliography (Ashkenazi, 2002;Aggarwal, 2003), correlates TNF-a, which initiates the TNFR1-TRADD-FADD-Caspase-8-Caspase-3 apoptotic pathway, with the antitumour effects shown after pulsed magnetic field stimulation (Yamaguchi et al, 2006). …”