Effects of intrathecal administration of FK506 after sciatic nerve crush injury.

Although various administration routes of FK506 have been published, intrathecal administration of FK506 has not previously been reported in the literature. A daily dose of 0.05 mg/kg of FK506 was given (a small dose compared with those reported in the available literature). The authors used this small dose to obtain lower immunosuppression and neurotoxicity, and a higher axonal regeneration rate. A total number of 40 female Wistar rats were used and randomly divided into four groups: control, sham, FK506-treated, and vehicle-treated. Sciatic nerve regeneration was evaluated by walking track analysis, an electrostimulation test, and light microscopic evaluation. There was a statistically significant difference ( P < 0.05) between FK506-treated and vehicle-treated groups at the end of 6 weeks according to both the walking track analysis and the electrostimulation test. Comparing the stimulus thresholds of the sham and FK506-treated group, no significant difference ( P > 0.05) was observed. Evaluation of the data revealed that FK506 had a beneficial effect on sciatic nerve regeneration.