Functional recovery of transected nerves treated with systemic BDNF and CNTF

The purpose of this study was to investigate the effect of systemic co-injections of ciliary neurotrophic factor (CNTF) and brain-derived neurotrophic factor (BDNF) on the functional recovery of transected sciatic nerves repaired by epineurial coaptation (EC) or collagen tubulization (CT). Forty Sprague-Dawley rats underwent transection of their sciatic nerves and repair by either EC or CT. With each repair technique, systemic injections of neurotrophic factors or control injections of lactated Ringer's solution were given. This resulted in four treatment groups: EC, EC + BDNF/CNTF, CT, and CT + BDNF/CNTF. Nerve function was assessed using sciatic functional indices (SFI). Animals whose nerves were repaired by CT (P = 0.01), CT + BDNF/CNTF (P = 0.04), and EC + BDNF/CNTF (P = 0.04) all had better functional recovery than those whose nerves were repaired by EC. There were no significant differences among these three groups, however. Animals in the CT group manifested the most rapid rate of recovery (P = 0.02 compared with EC). Collagen tubulization and systemic co-injections of BDNF/CNTF improve the rate and extent of sciatic functional recovery after nerve repair. The improvement in recovery conferred is not additive.