Ciliary neurotrophic factor enhances peripheral nerve regeneration

Background: Adjunctive measures to enhance nerve repair have focused on a variety of trophic factors that alter the physiologic response to nerve injury through Schwann cell-axonal interactions. Objective: To evaluate the effects of two trophic factors, ciliary neurotrophic factor and nerve growth factor, on axonal response to injury. Design: A prospective, randomized, blinded animal study with a placebo control using lactated Ringer's solution. Interventions: Rat sciatic nerves were transected and repaired as a model of injury following which experimental factors were delivered in vivo through an implantable osmotic pump. Outcome Measures: Functional nerve recovery, muscle mass, and gene expression in the three experimental groups were evaluated. Results: The ciliary neurotrophic factor group (n=6) showed a higher sciatic functional recovery (P=.003) and preservation of affected muscle mass (P=.03) compared with the nerve growth factor (n=8) and control (n=8) groups. Molecular analysis of injured nerves showed no difference in expression of ciliary neurotrophic factor, myelin basic protein, or low-affinity neurotrophin receptor messenger RNA among the three groups. Conclusion: These data suggest that ciliary neurotrophic factor may serve as an important neurocytokine for axonal regrowth during peripheral nerve regeneration.