Ameliorating effects and mechanisms of therapeutic electrical stimulation on the recurrent laryngeal nerve injury model in rats

Recurrent laryngeal nerve (RLN) injury is a rare but serious complication of thyroid surgery and other neck surgery, leading to vocal fold paralysis. The aim of this study was to investigate the therapeutic effects and mechanisms of therapeutic electrical stimulation (TES) on RLN regeneration in a rat model of RLN crush injury. Sprague–Dawley rats were randomly divided into groups of RLN injury and RLN injury + TES, and received RLN injury operation. The RLN injury + TES group received daily recurrent laryngeal nerve electrical stimulation for 14 days. Functional recovery including vocal fold mobility scoring and electrophysiological measurements was assessed. Structural changes were evaluated using histology and transmission electron microscopy. In comparison with observation management, TES improved vocal fold mobility(p < 0.01) on direct observation, reduced latency and attenuated amplitude loss (p < 0.05) on electrophysiological analysis, promoted fibroblast activation and angiogenesis on histology, and enhanced remyelination and axonal integrity on ultrastructural analysis. The results show that TES accelerates the early phase of functional and structural recovery following RLN injury, as evidenced by improved vocal fold mobility, electrophysiological parameters, and ultrastructural organization at 14 days post-injury.