Bio-effects of extremely low frequency electromagnetic fields (60 Hz.) on the healing of corneal epithelial wound: an...

The organ cultures of standardized epithelial wound of rabbit cornea, were exposed to electric and magnetic fields components of the extremely low frequency (60 Hz) sinusoidal electromagnetic field, separately or in combination. The electric field was applied as a pure electric current via an agar-salt bridge, and the magnetic field component was applied as a pure polarized magnetic field by means of a pair of energized coils in a Helmholtz configuration. The two field components were at right angles to each other and in phase (phi = 0 degrees) when applied in combination. Their vectors or planes of polarization were parallel to the surface of the culture dish. The three exposure combinations used were: a) electric current density of 0.19 V/m (30 microA/cm2) and/or magnetic fields strength of 1.0 Gauss. (low intensity) b) electric current density of 0.31 V/m (50 microA/cm2) and/or magnetic fields strength of 1.5 Gauss. (medium intensity) c) electric current density of 0.57 V/m (90 microA/cm2) and/or magnetic fields strength of 2.5 Gauss. (high intensity). After 2 days of exposure the incorporation of radiolabelled thymidine into DNA of the regenerating epithelial cells was determined. Results showed thymidine incorporation (adjusted by regression for differences in the levels of DNA in corneal wound) (DNA*) depended upon the electromagnetic field strength. The only significant effect on this outcome, was an interaction effect between the electric (E) and magnetic (M) fields employed. The size and direction of this interaction depended strongly on the maximum field strengths. At the lowest level DNA* was significantly lower when both fields were present than would be expected from the effects of either field alone. At the highest level, DNA* was significantly higher. There were no significant effects for medium field strengths.