KERATOCYTE GAP JUNCTIONAL COMMUNICATION IN NORMAL AND WOUNDED RABBIT CORNEAS AND HUMAN CORNEAS

Purpose, Several studies have indicated the anatomic and biochemical p resence of gap junctions in corneal keratocytes. The current study was designed to demonstrate that these gap junctions are functional in ra bbit and human corneal keratocytes. This study also examined dye coupl ing between keratocytes migrating into the wound region of freeze woun ded rabbit corneas. Methods. Freeze wounds were created on anesthetize d rabbit corneas using a liquid nitrogen-cooled brass probe. Freeze-wo unded corneas were examined at several time periods from days 0 to 5 a fter wounding. Nonwounded rabbit corneas also were examined. Human cor neal buttons were examined immediately after removal from patients who underwent keratoplasty. Gap junctional coupling was examined by micro injecting carboxyfluorescein from microelectrodes into the basal-most keratocytes and capturing dye spread images with a cooled charge coupl ed device camera. Results, Significant dye spread was observed between cells in the unwounded areas of corneas at wound time 0 and between c ells migrating into the wound areas as early as 24 hours after woundin g. In control corneas, dye spread to as many as 50 cells from the sour ce cell. Dye spread also was seen between keratocytes in human corneas with pseudophakic bullous keratopathy and keratoconus. Conclusions. G ap junctions observed in keratocytes from normal rabbit corneas are fu nctional. Gap junctions also are present and functional in keratocytes within unwounded and wounded regions of freeze-injured corneas. In ad dition, functional gap junctions are present between keratocytes in hu man corneas. This study confirms the long-held contention that corneal keratocytes form a large intercommunicating network within the cornea l stroma.