Enhanced reinnervation of the paralyzed orbicularis oculi muscle after insulin-like growth factor-I (IGF-I) delivery to a nerve graft

Facial paralysis (FP) remains today one of the most disturbing cranial nerve disorders. The present study utilized the rat model of FP and examined a dual approach of combining the current microsurgical treatment of cross-facial nerve graft (CFNG) with local administration of insulin-like growth factor-I (IGF-I). The efficacy of this combined treatment approach was assessed by motor end-plate analysis of the reinnervated orbicularis oculi muscle (OOM). Local administration of IGF-I (50 μg/ml) to the CFNG demonstrated a 61 percent increase in the number of end-plates in the reinnervated OOMs, compared to the OOMs reinnervated with CFNG plus vehicle. These results indicate that the local therapeutic augmentation of IGF-I levels at the coaptation site(s) of the CFNG may, in fact, enhance reinnervation of muscle and recovery of function in general.