Effect of high-density extremely low frequency magnetic field on sister chromatid exchanges in mouse m5S cells

The induction of sister chromatid exchanges (SCEs) was evaluated in the cul tured mouse m5S cells after exposure to extremely low frequency magnetic fi eld (ELFMF; 5, 50 and 400 mT). Exposure to 5 mT and 50 mT ELFMF led to a ve ry small increase in the frequency of SCEs, but no significant difference w as observed between exposed and unexposed control cells. The cells exposed to 400 mT ELFMF exhibited a significant elevation of the SCE frequencies. T here was no significant difference between data from treatments with mitomy cin-C (MMC) alone and from combined treatments of MR;IC plus ELFMF (400 mT) at any MMC concentrations from 4 to 40 nM. These results suggest that expo sure to highest-density ELFMF of 400 mT may induce DNA damage, resulting in an elevation of the SCE frequencies. We suppose that there may be a thresh old for the elevation of the SCE frequencies, that is at least over the mag netic density of 50 mT. (C) 1999 Elsevier Science B.V. All rights reserved.