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.