Faculty Collaboration Database

Intraocular Axon Regeneration in a Model of Penetrating Eye Injury. J Ocul Pharmacol Ther 2023 Oct;39(8):563-571

Date

07/24/2023

Pubmed ID

37486664

Pubmed Central ID

PMC10616938

DOI

10.1089/jop.2023.0048

Scopus ID

2-s2.0-85167663680 (requires institutional sign-in at Scopus site)

Abstract

Purpose: Penetrating eye injuries commonly cause permanent loss of vision in patients. Unlike mammals, zebrafish can regenerate both damaged tissue and severed axons in the central nervous system. Here, we present a tractable adult zebrafish model to study intraocular axon regeneration after penetrating eye injury. Methods: To create consistent penetrating intraocular injuries, pins of standardized diameters were inserted into the eye through the cornea and penetrating the retina but not the underlying sclera. Transgenic gap43:GFP reporter fish were used to preferentially label retinal ganglion cells (RGCs) that respond to injury with regenerating axons. Retinas were fixed and flat mounted at various times postinjury to examine injury size, number of green fluorescent protein (GFP)-positive cells and axons, axonal varicosities, and rate of regeneration to the optic nerve head. Intraocular injection of colchicine was used to inhibit axon outgrow as a proof of principle that this method can be used to screen effects of pharmacological agents on intraocular axon regeneration. Results: Penetrating injury to the zebrafish retina results in robust axon regeneration by RGCs around and beyond the site of injury. The gap43:GFP transgene allows visualization of individual or small bundles of axons with varicosities and growth cones easily observable. Regeneration proceeded with most, if not all, axons reaching the optic nerve head by 3-day postinjury. A single intraocular injection of colchicine a day after injury was sufficient to delay axon regeneration at 2-days postinjury. Surprisingly, we identified a stereotypically located population of circumferential projecting neurons within the retina that upregulate gap43:GFP expression after injury. Conclusions: Penetrating injury to the adult gap43:GFP transgenic zebrafish eye is a model of successful intraocular axon regeneration. The pharmacological and genetic tools available for this organism should make it a powerful tool for dissecting the cellular, molecular, and genetic mechanisms of axon regeneration in the intraocular environment.

Author List

Hu M, Veldman MB

Author

Matthew B. Veldman PhD Assistant Professor in the Cell Biology, Neurobiology and Anatomy department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Animals
Axons
Colchicine
Eye Injuries, Penetrating
Humans
Mammals
Nerve Regeneration
Zebrafish