Nimodipine accelerates reinnervation of denervated rat thyroarytenoid muscle following nerve-muscle pedicle implantation.

Abstract

OBJECTIVES/HYPOTHESIS: To determine whether nimodipine, an L-type voltage-operated calcium channel antagonist that is an accelerator of axonal regeneration following peripheral nerve injury, can expedite reinnervation of denervated rat thyroarytenoid (TA) muscle following nerve-muscle pedicle (NMP) flap implantation. STUDY DESIGN: A quantitative histologic and physiologic assessment of the TA muscle following NMP flap implantation, with or without nimodipine treatment. METHODS: Using 72 Wistar rats, we performed a transection on the left recurrent laryngeal nerve, followed by NMP flap implantation. Thirty-six animals received nimodipine treatment (NIMO [+] group), and the remaining 36 animals received no nimodipine treatment (NIMO [-] group). As a control, 18 animals were subjected only to transection of the left recurrent laryngeal nerve. We performed a histologic assessment for muscle area, axon, nerve terminals (NTs), and acetylcholine receptors (AchRs) in the TA muscle and electromyography at 2, 4, and 10 weeks after surgery. RESULTS: Muscle area, ratio of the number of NTs to that of AchRs (NT/AchR ratio), and evoked action potential in the TA muscle were significantly greater in the NIMO (+) group than in the NIMO (-) group (P < .05) at 4 weeks. At 10 weeks, the NT/AchR ratio was significantly greater in the NIMO (+) group than in the NIMO (-) group (P < .05). CONCLUSIONS: We found that nimodipine accelerated reinnervation of the denervated TA muscle following NMP flap implantation.