The Central Mechanism Of Accessory Nerve Transposition Of Phrenic Nerve To Reconstruct The Respiratory Function Of Rats With High Cervical Spinal Cord Injury

[objective] In patients with high cervical spinal cord injury,respiratory function is lost and mortality is very high.In order to reduce the death rate of such patients,it is very important to rebuild their autonomic respiratory function.It is supported by the National Natural Fund that the respiratory function of rats with high cervical spinal cord injury was successfully reconstructed by accessory nerve transposition of phrenic nerve and the animal model was established.The purpose of this study was to reveal the central mechanism of reconstructing respiratory function after accessory nerve transposition of phrenic nerve by means of retrograde tracing of adeno-associated virus,pseudorabies virus and immunohistochemical staining in rats with high cervical spinal cord injury.In order to further apply the methodology to clinical practice to provide a more solid theoretical basis.[method] Adult male SD rats were used as experimental animals.The accessory nerve and phrenic nerve were injected with adeno-associated virus(AAV-Retro-GFP)and the motor neurons innervating the accessory nerve and phrenic nerve of normal SD rats were traced retrograde through a single synapse.The accessory nerve and phrenic nerve were injected with pseudorabies virus(PRV-CMV-EGFP)to retrograde the anterior motor neurons and their related nuclei innervating the accessory and phrenic nerves of normal SD rats.By using immunohistochemical method,specific double labeling was carried out on the above virus labelled nuclei to further confirm the viral labeled neuronuclei.In the sa me method,after 6 months accessory nerve transposition of phrenic nerve,AAV-Retro-GFPA and PRV-CMV-EGFP were injected into the distal end of anastomotic nerve anastomosis to track retrograde the autonomic motor nerve,anterior motor neurons and related nuclei of diaphragm of SD rats.The specific antibody was used to double label the viral labeled nuclei to further confirm the viral labeled neuronuclei.Finally,by comparing the changes of neural anastomotic motor neuron,anterior motor neuron and related nucleus of the phrenic nerve,accessory nerve of normal SD rats and after nerve transposition.The changes of central mechanism of reconstructed respiratory function in SD rats with high cervical spinal cord injury after nerve transposition were preliminarily revealed.[result](1)normal SD rats:The motoneurons innervating the branches of the trapezius of the accessory nerve are mainly concentrated in the nucleus reticularis oblongata.The anterior motor neurons that innervate the accessory nerve are mainly concentrated in the nucleus tractus solitarii,the medullary raphe.The motoneurons innervating phrenic nerve are mainly concentrated in the anterior horn of the spinal cord of C4-C6 in the cervical spinal cord,and the anterior motor neurons innervating the phrenic nerve are mainly concentrated in the ventral respiratory group,the nucleus of the solitary tract of the medulla oblongata,the raphe of medulla oblongata and the superior olivary nucleus.(2)SD rats after nerve transfer:The motor neurons innervated the anastomoses are mainly concentrated in the nucleus reticularis nucleus.The former motor neurons innervated the anastomosed nerves are mainly concentrated in the nucleus of the solitary tract,the nucleus of the medulla and the nucleus of the facial nerve.[conclusion] 6 months after nerve transposition,the accessory nucleus and / or superior neurons were remodeled to form synapses identical or similar to those of ventral respiratory group neurons,and eventually to form the ‘accessory nucleus ?Accessory nerve?Phrenic nerve?Diaphragm' pathway.And rhythmic electrical impulses are produced by the neurons of the accessory nucleus,which innervate the diaphragm through anastomosis and reconstruct the respiratory function of the rats after the injury of the high cervical spinal cord.