Differential effects of radio frequency magnetic fields in vitro and in vivo

Abstract

Differential effects of RF magnetic fields in vitro and in vivoBackgroundThe present study investigates effects of radio frequency (RF) magnetic fields in the range 1–15 MHz on growth of cancer cells in vitro and in mice models. Most biomolecules have hyperfine splitting constants ranging from 0.1–10 MHz, which gives the basis for the chosen frequencies.MethodsFor in vitro experiments, fibrosarcoma cell line was treated 15 minutes a day with a combination of magnetic fields: 45 μT static fields in perpendicular and at 40 degrees to an RF signal. The exposures to an RF signal ranging from 5–10 MHz were conducted at a specific absorption rate (SAR) of 0.001, 0.01, 0.05 and 0.2 W/kg using continuous waves (CW). For in vivo experiments, mice with fibrosarcoma and pancreatic tumors were exposed continuously to low‐level static magnetic fields (0.5–2 μT) and a combination of 45 μT static fields in perpendicular to 10 MHz. All controls were exposed to the geomagnetic field (45 μT).ResultsA growth response curve as a function of SAR level is obtained indicating distinct effects for the SAR range used: inhibition of cellular proliferation is obtained for SAR level of 0.001 W/kg; SAR levels of 0.05 and 0.2 W/kg enhances proliferation in vitro. In vivo, 10 MHz magnetic fields inhibit tumor growth in mice as much as 35 percent on day 18 of exposure.ConclusionWe have shown that even a physically weak magnetic field can alter cellular growth. RF magnetic fields modulated proliferation of cancer cells both in vitro and in vivo. The exposure levels were below standard threshold levels for thermal effects due to electromagnetic radiation.