Chapter 47 Fetal brain grafts promote axon regeneration and survival of adult rat retinal ganglion cells

Publisher Summary Axon regeneration in the adult CNS can be stimulated by transplantation of peripheral nervous tissue and occurs in the immature mammalian CNS, and fetal brain grafts induce regeneration of adult central axons. This chapter describes the effects of fetal brain grafts on axon regeneration and neuron survival in the visual system, where fetal target regions are transplanted to the cut end of the optic nerve. The results show that fetal target regions transplanted to the cut optic nerve influence both the survival and the regeneration of adult retinal ganglion cells. Axotomy-induced neuron death is thought to be because of the interruption of the retrograde flow of neurotrophic molecules from target to soma. However, it cannot be excluded that the survival promoting effects of the graft are mediated indirectly through host glia that have been induced to secrete neurotrophic factors by the grafts in the early post operation period. The attraction of regenerating axons to the grafts indicates that the transplants are able to direct growth of at least a small proportion of the axons present at the site of transection. Thus, a gradient of diffusible neurite elongation factors released by the graft might attract regenerating axons and such factors await further analysis and tests in vivo .