Effect of FK506 on axonal regeneration of rat sciatic nerve in regeneration chamber: an experimental study

Objective To evaluate the effect of FK506 on expediting nerve regeneration of rat Sciatic Nerve in regeneration chamber and to look for a proper way of its administration to treat peripheral nerve injuries.Methods Sixty adult male SD rats which were randermizely devided into 3 groups received a neurotomy to bilateral sciatic nerves, then we reconnected the broken nerves with silicon tube to make regeneration chambers. The regeneration chambers were filled with either normal saline (group A and group B) or 1 μg/ml FK506 (group C). The rats of group B also received daily injection of FK506 (1 mg/kg) at the back of the neck for 14 days. Local immunoreaction, weight of fresh gastrocnemius muscles, histological changes and electrophysiology were observed at designate time after neurotomy. Results At 6 weeks postoperation the extent of local lymphocytes infiltration in group B and C were less than that in group A, all results in group B were much better than that of group A. Results of group C were better than that of group A without significance. Conclusions (1) Systemic administration of FK506 (1 mg/kg) showed neuroprotective and neurotrophic effect, which can facilitate nerve regeneration and promote functional recovery. (2) Local administration of FK506 (1 μg/ml) showed some extent of neuroprotective effect at early period of nerve injuriy, but the neurotrophic function is uncertain and still needs to be studied further.