Recurrent laryngeal neuropathy (RLN) or “Roaring” is a major cause of poor athletic performance affecting 8% of racehorses and a higher percentage of sport horses. RLN produces axonal loss with demyelination with subsequent loss of cricoarytenoid dorsalis (CAD) muscle volume and inability to maintain an open airway. A number of reinnervation techniques have been used in an attempt to restore function of this muscle, however, these methods have not gained widespread clinical acceptance as the muscle response can take up to 12 months to occur. A surgical solution that maintains airflow by preserving CAD muscle mass and laryngeal function would be associated with improved performance outcomes.

Our goal is to use modification of the nerve microenvironment to improve the time to recovery and the quality of nerve graft repair. We focus on use of IL-10, a cytokine with known anti-inflammatory and immunomodulatory effects, applied to the nerve graft repair. We have already obtained strong preliminary data which support this approach.

Our first aim is to determine the effects of sustained IL10 delivery at the site of nerve injury. For this aim we use rats to increase our statistical power.  We determine effects on axon extension, neuromuscular junction formation and functional recovery.  Neuromuscular junction formation is important as it closely correlated to force generation of any given muscle, including the CAD muscle in the equine larynx.  Force generation by the CAD muscle is important to maintain a patent airway.  In the second aim we determine the time to recovery after graft to the recurrent laryngeal nerve in horses.