Effect of FK506 on functional recovery after facial nerve injury in the rat

Abstract

Objective: To examine the effect of the immunosuppressive agent FK506 on the rate of functional recovery of the rat facial nerve after crush injury.

Methods: Forty rats underwent facial nerve crush injury and were randomly assigned to 4 experimental groups: isotonic sodium chloride solution control, FK binding protein 52 (FKBP-52) antibody control, FK506, and FK506 and FKBP-52 antibody. Rats underwent daily recovery testing from postoperative day 9 until postoperative day 21 by videotaping 3 validated variables in this model: blink reflex return, vibrissial fibrillation loss, and return of vibrissial sweeping symmetry.

Results: FK506-treated animals demonstrated improved recovery in all 3 variables compared with control animals. The FK506 and FKBP-52 antibody group demonstrated improved recovery of only the return of the blink reflex.

Conclusions: FK506 accelerated functional recovery of facial nerve function after crush injury. Neuroregeneration was inhibited by FKBP-52 antibody in the rat midface but not the upper face. FK506 may be a viable adjuvant treatment for facial nerve neurapraxic injury.