Brain-derived neurotrophic factor and collagen tubulization enhance functional recovery after peripheral nerve transection and repair

Objective: To investigate the effect of brain-derived neurotrophic factor (BDNF) and collagen tubulization (CT) on the regeneration of transected peripheral nerves. Methods and Design: The left sciatic nerve of 40 Sprague- Dawley rats was transected then repaired using one of four techniques: epineurial coaptation, CT, CT with BDNF delivered by an osmotic pump to the repair site, or CT with BDNF covalently cross-linked to the collagen matrix (CT/linked-BDNF). Sciatic functional indices were measured preoperatively and then postoperatively at 10-day intervals for 90 days. Segments of the sciatic nerves proximal and distal to the repair site were harvested at 90 days for histologic and morphometric evaluation. Results: Animals repaired by CT/linked-BDNF (n=10) demonstrated the most favorable functional recovery of all groups, with statistically significant differences seen compared with animals repaired by CT (n=10, P=.05) and epineurial coaptation (n=9, P<.001). Animals repaired by CT with BDNF delivered by an osmotic pump (n=8) and CT also showed statistically superior functional recovery compared with those repaired by epineurial coaptation (P=.005 and P=.02, respectively). Nerves repaired by CT/linked-BDNF had the largest mean axon diameters proximal and distal to the repair site. Conclusions: Brain-derived neurotrophic factor and CT improve the rate and the degree to which recovery of sciatic function occurs after nerve transection and repair. Animals repaired by CT/BDNF- linked demonstrated the most favorable functional recovery of all groups. Animals whose repair technique included BDNF had the largest mean axon diameters of all groups.