An Experimental Study On Brain Functional Reorganization Of Different Contralateral C7 Oprative Modes Treat Total Brachial Plexus Avulsion In Young Rats

PartⅠIdentification of CNS neural circuitry involved in the innervation of the C7 nerve root:a viral transsynaptic tracing studyObjective The distribution of labeled positive neurons in the brain and spinal cord was studied after injecting the attenuated strain of pseudorabies virus(PRV) into the C7 nerve root so as to provide a baseline for further studying of brain functional reorganization after contralateral C7 was transfered.Method 20 adult Sprague Dawley rats were randomly divided into 4 groups according to the time of being sacrificed:6 hours,12 hours,24 hours and 36 hours groups.2ul of the virus was slowly injected into the right C7 nerve root. After survival times of 6-36 hours,the spinal cord(C1-C7) and brain were processed immunocytochemically using a polyclonal antibody against the PRV.Result PRV labeled positive neurons were found in some spinal cord and brain regions from 6 hours to 36 hours post injection,such as the gray matter in the C1-C7 spinal cord,the lateral paragigantocellular nuclei,and the A5 cells,red nucleus,primary and secondary motor cortex,primary and secondary somatosensory cortex et al.Increasing the number in viral labeling from the spinal cord to brain regions became apparent with increasing survival time.Conclusion The spinal cord and brain structures labelled from the C7 nerve root by the transsynaptic tracing technique are synaptically connected with C7 and presumably are involved in the neural regulation of C7.PartⅡA viral transsynaptic tracing study on brain functional reorganization of different contralateral C7 oprative modes treat total brachial plexus avulsion in young ratsObjective To study the brain functional reorganization and compare the influence on functional reorganization by different operative modes on young rat models after contralateral C7 transfer opration by viral transsynaptic tracing technique.Method The contralateral C7 was transferred to musculocutaneous nerve,both the musculocutaneous and median nerves and median nerve respectively in three young rat models groups 1.5,3,6,9 and 12 months later respectively,2ul PRV was injected to the recipient nerves.After 30-hours survival times,the forelimb representation of motor cortex was processed immunocytochemically,using a polyclonal antibody against the PRV to detect the positive neurons and study the difference of the amount of them among differert operative modes.Result The amount of positive neurons increased in both motor cortex after the contralateral C7 transfer operation in all experimental groups.During earlier period,there were more positive neurons in the left motor cortex than that in the right one.Otherwise in the advanced stage the results were opposite.The funcional reorganization pace were faster in contralateral C7-to -musculocutaneous nerve group and contralateral C7-to-both the musculocutaneous and median nerves group than contralateral C7-to-median nerve group(P＜0.01).Conclusion 1.There were changes of neural pathway in the brain functional reorganization after peripheral nerve injuries on young rats and the reorganization might be relevant with the formation of new neural pathway.2.the type of recipient nerve affected the brain functional reorganization after peripheral nerve injuries.To transfer contralateral C7 to musculocutaneous nerve or to both the musculocutaneous and median nerves were more beneficial to complete the functional reorganization across hemiphere.PartⅢAn electrophysiologicai study on brain functional reorganization of different contralateral C7 oprative modes treat total brachial plexus avulsion in young ratsObjective To study the brain functional reorganization and compare the influence on functional reorganization by different operative modes in young rats after contralateral C7 transfer opration by microelectrode electrical stimulation.Method The contralateral C7 was transferred to musculocutaneous nerve,both the musculocutaneous and median nerves and median nerve respectively in three young rat models groups.1.5,3,6,9 and 12months later respectively,cortical representation of repaired limb at both hemisphere motor cortex will be determined to study the difference in dynamic process of functional reorganization across hemisphere among differert operative modes.Result A dynamic across hemispherical functional reorganization corresponding to the repaired limb was observed after operation.Cortical representation of repaired limb was firstly located at the ipsilateral cortex,and then at both sides. As the time paces,it was finally observed in the contralateral motor cortex.The funcional reorganization results were better in contralateral C7-to -musculocutaneous nerve group and contralateral C7-to-both the musculocutaneous and median nerves group.Conclusion 1.Cortical representation of repaired limb can complete the across hemispherical functional reorganization after the contralateral C7 transfer operation in young rats.2.The pace and extent of the functional reorganization would be influnenced by the operative modes of the contralateral C7 transfer.To transfer contralateral C7 to musculocutaneous nerve or both the musculocutaneous and median nerves could lead to better functional reorganization results.