Retinal synthesis and axonal transport of gangliosides during regeneration of the goldfish optic nerve

Abstract

In the present study, the left optic nerve of the goldfish was transected between eye bulb and optic chiasm. One to 39 days after lesion, the fish received an intraperitoneal injection of [3H]proline or [3H]NAc-glucosaraine. After one or two days of incorporation, both retinae and optic nerves were analyzed for protein- and ganglioside-bound radioactivity. A transient enhancement of label incorporation into proteins (up to 2-fold) and gangliosides (up to 1.5-fold) of the regenerating retina was found. Simultaneously, a transiently enhanced accumulation (up to 4.5-fold) of protein- and ganglioside-bound radioactivity in the regenerating optic nerve took place. These regeneration-related 'metabolic' changes came to a maximum at 6-8 days after nerve transection and were still measurable after 40 days. In the regenerating retina, there were no changes either of the ganglioside pattern or of the relative distribution of radioactivity of individual gangliosides. In the regenerating optic nerve, however, ganglioside GPlc, identified by immuno-TLC, and a fraction migrating like GD3/GM1 were enhanced with respect to their relative proportion of total ganglioside sialic acid and radioactivity. The radioactivity proportion of a ganglioside migrating like GDlb was decreased.