Repairing Injured Optic Nerve of Rat with Several Therapies

Abstract

Optic nerve of mammalian, as brain and spinal cord, is difficult to regenerate successfully after injury. It is one of research focuses and difficult projects how to promote regeneration of injured optic nerve in the neuroscience and ophthalmology. We have explored to repair the injured optic nerve of rat with several therapeutic strategies in the recent years. (1)Physical therapy: In a rat model of optic nerve crush, hyperbaric oxygen preconditioning or hydrogen‐rich saline administered intraperitoneally could decrease apoptosis of retinal ganglion cells, promote their survival, and improve visual functional restoration as pupillary light reflex and visual evoked potential. (2)Cell therapy: Rat amniotic epithelial cells (AECs) with some characteristics of stem cells, AECs transfected by basic fibroblast growth factor gene, or AECs seeded in the collagen sponge was implanted into the injured region of rat optic nerve transected. These three therapies could increase the survival of retinal ganglion cells after injury of rat optic nerve. The cells could guide the regenerating axon to extend into the injured region, and promote a few of axons to cross the injured region into 1‐2 mm in the distal optic nerve. (3)Gene therapy: After neuritin lentivirus infection of rat retina, the number of retinal ganglion cells and optic nerve axons were increased significantly after optic nerve crush, this protective effects was further confirmed by the functional tests as pupillary light reflex and visual evoked potential. After RGC5 damage in vitro, neuritin overexpression promoted neurite outgrowth which might be through the upregulation of phosphorylation of Akt and Erk, and reduced cell apoptosis which might be through the inhibition of caspase 3 activation.