Assaying Optic Nerve Regeneration in Larval Zebrafish.

Zebrafish have a remarkable capacity for spontaneously regenerating their central nervous system. Larval zebrafish are optically transparent and therefore are widely used to dynamically visualize cellular processes in vivo, such as nerve regeneration. Regeneration of retinal ganglion cell (RGC) axons within the optic nerve has been previously studied in adult zebrafish. In contrast, assays of optic nerve regeneration have previously not been established in larval zebrafish. In order to take advantage of the imaging capabilities in the larval zebrafish model, we recently developed an assay to physically transect RGC axons and monitor optic nerve regeneration in larval zebrafish. We found that RGC axons rapidly and robustly regrow to the optic tectum. Here, we describe the methods for performing the optic nerve transections, as well as methods for visualizing RGC regeneration in larval zebrafish.