Diaphragm recovery by laryngeal innervation after bilateral phrenicotomy or complete C2 spinal section in rats

• Published in: Neurobiology of disease Vol. 24; no. 1; pp. 53 - 66
• Main Authors: Gauthier, P., Baussart, B., Stamegna, J.C., Tadié, M., Vinit, S.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-10-2006; Elsevier
• Subjects: Anastomosis, Surgical; Animals; Breathing; Cordotomy; Denervation; Diaphragm; Diaphragm - innervation; Diaphragm - physiology; Electromyography; Electrophysiology; Female; Functional Laterality - physiology; Immunohistochemistry; Laryngeal motoneurons; Life Sciences; Medulla Oblongata - physiology; Paralysis - physiopathology; Phrenic Nerve - physiology; Phrenicotomy; Rats; Rats, Sprague-Dawley; Recurrent Laryngeal Nerve - physiology; Reinnervation; Spinal Cord - physiology; Spinal cord injury; LM; Laryngeal motoneurons; VRG; Phrenicotomy; Spinal cord injury; NA; RLN; SCI; Reinnervation; Diaphragm; Breathing; PN; APN; SPINAL CORD INJURY; LARYNGEAL MOTONEURONS; REINNERVATION; NEUROPHYSIOLOGIE; BREATHING; NEURONE MOTEUR; DIAPHRAGME; PHRENICOTOMY
• ISSN: 0969-9961; 1095-953X
• DOI: 10.1016/j.nbd.2006.05.002

This study aimed to highlight the functional aspects of diaphragm reinnervation by laryngeal motoneurons after bilateral phrenicotomy or complete cervical transection. The left recurrent laryngeal nerve was connected to the left phrenic nerve in 14 rats. Five months later, all bridged rats presented a substantial ipsilateral diaphragm recovery (74.2 ± 10% of contralateral activity) whereas the diaphragm remained paralysed in non-bridged rats (
n = 5/5). After additional right phrenicotomy, functional breathing persisted in bridged rats whereas all non-bridged died. After complete C2 spinal transection, diaphragm respiratory discharges persisted in bridged rats. The reinnnervation by laryngeal motoneurons was confirmed by retrograde labeling, stimulus-elicited diaphragm response by vagal stimulation and diaphragm inactivation after vagotomy. In conclusion, the recurrent-phrenic nerve anastomosis induces a reliable functional diaphragm outcome even after contralateral diaphragm denervation or complete high cervical spinal cord injury, and could be considered as a clinical repair strategy for re-establishing diaphragm autonomy following spinal cord trauma.