Objective: To investigate the neuroattract growth effect of Ciliary neurotrophic factor (CNTF) on recurrent laryngeal nerve (RLN) regeneration.
Methods: 28 canines were divided into 4 groups (n = 7). RLN was severed and sutured in silicone chamber. CNTF or saline were injected into silicone chambers during nerve repair and injected subcutaneously every day after surgery in group A and B respectively. In group C and D, end to end anastomosis of RLN was performed, and CNTF or saline was used respectively for one month. The nerve regeneration and neuroattract growth effect were evaluated with electrophysiological, morphological examination and horseradish peroxidase(HRP) retrograde tracing 2, 3 and 4 months postoperatively.
Results: Physiological adductory and adductory motion was observed in all 7 cases in group A and C respectively, and in 3 cases in group B. No motion in group D. Misdirected electrical activity by misdirected nerve regeneration was found in 3 cases in group B and 6 cases in group D. On average, the potential of misdirected electrical activity in group D was significantly greater than that in group B (P < 0.05). Compared with group B, the number of HRP retro-gradely labeled motoneuron increased significantly in group A in ambiguous nucleus, but in nodosity shape ganglia the number of the labeled neurons were not significantly different between group A and B. The average number and diameter of myelinated axons in the group A and C were significantly greater than those in group B and D, but no significant difference was found between group A and B, D and C respectively.
Conclusion: The results suggested that exogenous CNTF can enhance motor axon regeneration and have neuroattract growth effect on recurrent laryngeal nerve regeneration.