Synergistic effect of Nogo-neutralizing antibody IN-1 and ciliary neurotrophic factor on axonal regeneration in adult rodent visual systems

The presence of Nogo axon regeneration inhibitory molecules in the central nervous system (CNS) and the counteracting effect of IN-1 antibodies have been widely reported. In this study, we examined the effect of IN-1-producing hybridoma cells on axon regeneration in adult rodent retinal ganglion cells (RGCs) after various types of optic nerve (ON) injury, evaluating therein whether ciliary neurotrophic factor (CNTF) potentiated the effect of IN-1. We found that application of IN-I alone failed to enhance regeneration of intracranially or intraorbitally transected RGC axons in a peripheral nerve (PN) graft. IN-1 hybridoma cells also failed to significantly promote intraorbitally crushed ON axons to reenter the distal part of the ON. However, a combined application of IN-I and CNTF had a synergistic effect in both intracranial PN and intraorbital ON crush paradigms. This study suggests that the action of IN-1 antibodies in promoting axon regeneration in the CNS could be more effective when coupled with other appropriate factors.