ABSTRACT
Damage to the adult mammalian optic nerve (ON) usually results in the degeneration of the ON and death of retinal ganglion cells (RGCs), leading to permanent loss of visual functions. New strategies, especially the transplantation of a peripheral nerve (PN) to the retina or transected ON, have been created to promote the neuronal survival and axonal regeneration of axotomized RGCs. In this review, we focus on how a PN and other factors are used to overcome the unfavorable extrinsic CNS environment and the lack of trophic factors, and upregulate the intrinsic growth potential of the axotomized neurons since recent studies suggest that the lack of intrinsic growth potential in the CNS neurons is also an important factor contributing to the failure of CNS regeneration.