ELECTRICAL STIMULATION OF THE DAMAGED OPTIC NERVE

PREVIOUS STUDIES HAVE SUGGESTED THAT APPLIED ELECTRIC FIELDSCAN EFFICACIOUSLY FACILITATE THE FUNCTIONAL OUTCOME OF CNS INJURY IN RODENTS. WHETHER THE EFFECTS OF ELECTRIC FIELDS INVOLVE A REGENERATIVE RESPONSES IN THE CNS CAN ONLY BE ANSWERED BY USING A MODEL SYSTEM THAT PROVIDES A DEFINITE SOURCE OF AXONS WHICH CAN BE INTERRUPTED AND STUDIED FOR REGROWTH. THE RAT OPTIC NERVE IS SUCH A SYSTEM AND WILL BE USED IN THESE STUDIES. THE OPTIC NERVES OF RATS WILL RECEIVE A UNILATERAL CRUSH/FREEZE LESION THAT INTERRUPTS THEAXONS, WHILE LEAVING THE VASCULATURE INTACT. GROUPS OF ANIMALS WILL THEN BE IMPLANTED WITH ELECTRIC FIELD STIMULATORS DELIVERING ONE OF THREE CURRENT LEVELS TO THE DAMAGED OPTIC NERVE. CONTROLS WILL RECEIVE INACTIVE STIMULATORS. AT SELECTED TIME PERIODS, THE OPPOSITE EYE IS ENUCLEATED AND THE LESIONED SIDE IS INJECTED WITH HRP. AFTER ALLOWING TWO DAYS FOR AXONAL TRANSPORT, THE ANIMALS ARE SACRIFICED AND THE RETINAE, OPTIC NERVES, OPTIC TRACTS AND LATERAL GENICULATE BODIES ARE REMOVED AND ANALYZED FOR THE PRESENCE OF HRP. BY TRACING HRP THROUGH THE LESION SITE, AND DETERMINING ITS PRESENCE IN THE MORE CENTRAL PORTIONS OF THE VISUAL SYSTEM, WE WILL BE ABLE TO DETERMINE WHETHER ELECTRIC FIELDS CAN FACILITATE REGENERATION, AND TO WHAT EXTENT THEY HAVE SUCH AN EFFECT. PREVIOUS STUDIES HAVE SUGGESTED THAT APPLIED ELECTRIC FIELDSCAN EFFICACIOUSLY FACILITATE THE FUNCTIONAL OUTCOME OF CNS INJURY IN RODENTS. WHETHER THE EFFECTS OF ELECTRIC FIELDS INVOLVE A REGENERATIVE RESPONSES IN THE CNS CAN ONLY BE ANSWERED BY USING A MODEL SYSTEM THAT PROVIDES A DEFINITE SOURCE OF AXONS WHICH CAN BE INTERRUPTED AND STUDIED FOR REGROWTH. THE RAT OPTIC NERVE IS SUCH A SYSTEM AND WILL BE USED IN THESE STUDIES. THE OPTIC NERVES OF RATS WILL RECEIVE A UNILATERAL CRUSH/FREEZE LESION THAT INTERRUPTS THEAXONS, WHILE LEAVING THE VASCULATURE INTACT. GROUPS OF ANIMALS WILL THEN BE IMPLANTED WITH ELECTRIC FIELD STIMULATORS DELIVERING ONE OF THREE CURRENT LEVELS TO THE DAMAGED OPTIC NERVE. CONTROLS WILL RECEIVE INACTIVE STIMULATORS. AT SELECTED TIME PERIODS, THE OPPOSITE EYE IS ENUCLEATED AND THE LESIONED SIDE IS INJECTED WITH HRP. AFTER ALLOWING TWO DAYS FOR AXONAL TRANSPORT, THE ANIMALS ARE SACRIFICED AND THE RETINAE, OPTIC NERVES, OPTIC TRACTS AND LATERAL GENICULATE BODIES ARE REMOVED AND ANALYZED FOR THE PRESENCE OF HRP. BY TRACING HRP THROUGH THE LESION SITE, AND DETERMINING ITS PRESENCE IN THE MORE CENTRAL PORTIONS OF THE VISUAL SYSTEM, WE WILL BE ABLE TO DETERMINE WHETHER ELECTRIC FIELDS CAN FACILITATE REGENERATION, AND TO WHAT EXTENT THEY HAVE SUCH AN EFFECT.