Specific ion fluxes generate cornea wound electric currents

Abstract

The corneal epithelium generates a significant trans-epithelial potential (TEP) which aids in maintaining cornea water balance and transparency. Injury to the cornea causes a short circuit of the TEP at the wound. The TEP in the intact epithelium around the wound acts like a battery, powering significant ion flux and electric current at the wound. These circulating endogenous currents generate an electric field orientated towards the wound, with the wound the cathode. Many cell types, including human corneal epithelial cells and keratinocytes, migrate to the cathode at physiological electric field strengths. Indeed, the electric signal is a powerful stimulator of cell migration, which appears to override other cues such as chemotaxis and wound void. These wound fields also have a dynamic timecourse of change after wounding. It has been assumed that wound electric fields are produced by passive leakage of ions from damaged cells and tissue. Could these fields be actively maintained and regulated as an active wound response? What are the molecular, ionic and cellular mechanisms underlying the wound electric currents?