EFFECTS OF LOW-INTENSITY AC AND OR DC ELECTROMAGNETIC-FIELDS ON CELL ATTACHMENT AND INDUCTION OF APOPTOSIS/

Rat tendon fibroblast (RTF) and rat bone marrow (RBM) osteoprogenitor cells were cultured and exposed to AC and/or DC magnetic fields in a t riaxial Helmholtz coil in an incubator for up to 13 days. The AC field s were at 60 and 1000 Hz and up to 0.25 mT peak to peak, and the DC fi elds were up to 0.25 mT. At various combinations of field strengths an d frequencies, AC and/or DC fields resulted in extensive detachment of preattached cells and prevented the normal attachment of cells not pr eviously attached to substrates. In addition, the fields resulted in a ltered cell morphologies. When RTF and RBM cells were removed from the fields after several days of exposure, they partially reattached and assumed more normal morphologies. An additional set of experiments des cribed in the Appendix corroborates these findings and also shows that low-frequency EMF also initiates apoptosis, i.e., programmed cell dea th, at the onset of cell detachment. Taken together, these results sug gest that the electromagnetic fields result in significant alterations in cell metabolism and cytoskeleton structure. Further work is requir ed to determine the relative effect of the electric and magnetic field s on these phenomena The research has implications for understanding t he role of fields in affecting bone healing in fracture nonunions, in cell detachment in cancer metastasis, and in the effect of EMF an orga nisms generally. (C) 1997 Wiley-Liss. Inc.