Functional Recovery after Nerve Repair with Administration of Anti−TNF−a.

Methods: Regeneration of the sciatic nerve was assessed in C57–black–6 mice. Under general anaesthesia (Fentanyl/Fluanisone 0.8ml/kg [Janssen] & Midazolam 4mg/kg [Roche], i.p.) the nerve was sectioned and repaired using 4 epineurial sutures. In one group (10 animals/group) Etanercept (15μg in 100μl of water carrier) was injected into and around the proximal and distal nerve stumps using a microdialysis cannula. A second group had 100μl of water injected alone, and these acted as controls. After 6 weeks the extent of regeneration was assessed electrophysiologically by determining the ratio of the compound action potential (CAP) modulus evoked by electrical stimulation of the nerve 2mm distal and proximal to the repair site, and the conduction velocities of the fastest fibres.

Results: The median CAP ratio in the Etanercept group was 0.68, which was significantly higher than the control group (0.37, p<0.005, Unpaired t-test). Conduction velocities of fibres distal to the repair were not significantly different between groups (p>0.05).

Conclusion: Our method and dosage for administration of TNF–a antagonist Etanercept at a time of nerve repair significantly improves functional regeneration of sectioned axons in the mouse sciatic nerve.

Supported by the Royal College of Surgeons of Edinburgh (RCS 125796)