ABSTRACT
Objective:To explore the expression and distribution of ciliary neurotrophic factor (CNTF) in laryngeal nerve degeneration and regeneration. Methods:Transection of the recurrent laryngeal nerves in 8 dogs and suture following transection in 12 cases were performed. Both proximal and distal ends of transected or sutured region were sectioned at various survival times for CNTF immunohistochemistry and CNTF mRNA in situ hybridization. The area and intensity of reactive product were measured by computer image processing system. Results:After nerve transection, reactive product of CNTF mRNA and its protein reduced rapidly in distal stumps, after neurorrhaphy, they were observed in thin Schwann cell processes ensheathing axons and not found in the proliferating Schwann cells which didn′t ensheathe axons. CNTF immunoreactivity was also detected in the regenerated nerve axons. CNTF expression increased with survival time, but even at the longest survival time, it was still significantly less than that in intact nerve. The same change was observed in a short segment proximal to the transected or sutured region. Conclusion:CNTF expression is in the down regulation and is collected with Schwann cell axon in peripheral nerve degeneration and regeneration. The changed distribution of CNFT might provide a supportive environment for axonal regeneration.