IMPOSITION OF A PHYSIOLOGICAL DC ELECTRIC-FIELD ALTERS THE MIGRATORY RESPONSE OF HUMAN KERATINOCYTES ON EXTRACELLULAR-MATRIX MOLECULES

Outwardly directed ionic currents have been measured leaving skin woun ds in vivo. These currents generate physiologic electric fields of app roximately 100 mV/mm, which may function to direct keratinocyte migrat ion toward the healing wound, We investigated whether the substrate on which the keratinocyte migrates modulates the galvanotactic response to an electric migratory signal, Cultured human keratinocytes were pla ted on different matrices: types I and IV collagen, fibronectin, lamin in, and tissue culture plastic. The effect of an applied direct curren t (DC) electric field on directional migration was monitored by time-l apse video microscopy over a 2-h period. Directionality was quantitate d by calculating the cosine of the angle of migration in relation to a nodal-cathodal orientation. Migration toward the negative pole was obs erved on all matrices as compared with controls (no applied field), wh ich displayed random migration. No significant increase in directional response occurred when the field strength was increased from 100 mV/m m (physiologic levels) to 400 mV/mm, The degree of directionality and the average net cell translocation, however, varied significantly with the substrate, The greatest cathodal migration in response to a DC el ectric held was observed with keratinocytes plated on types I and IV c ollagens and plastic, The directional migratory response was least on a laminin substrate, whereas cells on fibronectin demonstrated a respo nse that was intermediate between those of collagen and laminin. These results suggest that physiologic ionic currents in concert: with the underlying matrix may influence the of skin wounds.