DIFFERENTIAL REGULATION OF C-JUN EXPRESSION IN RAT RETINAL GANGLION-CELLS AFTER PROXIMAL AND DISTAL OPTIC-NERVE TRANSECTION

In adult rats, the distance between the site of axotomy and the cell b ody influences the ability of retinal ganglion cells (RGCs) to survive and regenerate an axon. Optic nerves of adult rats were transected 2 mm or 6 mm from the optic bulb and RGCs labeled with the fluorescent m arker fluorogold. The time course of c-JUN expression was monitored im munocytochemically between 3 days and 4 weeks after axotomy. c-JUN exp ression began later aad declined faster after distal axotomy than afte r proximal transection of the optic nerve. However, at the same time s ignificantly more RGCs survived after distal than after proximal axoto my 3 and 4 weeks after axotomy. These findings suggest that survival a nd expression of c-JUN in rat RGCs are independently regulated by the length of the optic nerve stump after lesion.