Survival and Regeneration of Adult Spinal Motoneurons After Root Avulsion

Download or read book Survival and Regeneration of Adult Spinal Motoneurons After Root Avulsion written by Lai-Fung Li and published by Open Dissertation Press. This book was released on 2017-01-27 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Survival and Regeneration of Adult Spinal Motoneurons After Root Avulsion: a Comparison of Influence From Different Targets" by Lai-fung, Li, 李禮峯, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of dissertation entitled "Survival and regeneration of adult spinal motoneurons after root avulsion - A comparison of influence from different targets" Submitted by LI Lai Fung for the degree of Master of Research in Medicine at The University of Hong Kong in May 2005 Spinal root avulsion is a common event that results in motoneurons death and associated with NOS expression due to the injury. It was demonstrated that implantation of peripheral nerve graft could promote axonal regeneration but pioneer work with ventral root reimplantation on human did not give satisfactory result. One of the possibilities may associate with the method of implantation. It was shown that either the method of implanting the nerve into a cut made onto the spinal cord or just keeping the nerve in contact with spinal cord surface could result in axonal regeneration but it was unclear which one was better. On the other hand, neurotrophic support, e.g. in form of neurotrophic factors, from innervation target may also play a role. In this study, the effects of the two surgical implantation methods was studies in hope of providing further information for future surgical treatment. Moreover, different innervation targets on axonal regeneration of motoneurons as well as NOS expression were investigated in order to bring a better insight on mechanism of regeneration and degeneration of motoneurons. Adult SD rats were used in this study and were divided into two groups that each group would receive peripheral nerve graft implant by one of the mentioned surgical methods after C7 spinal root avulsion. Each group was then further divided into four subgroups. Each subgroup would have the distal end of the nerve graft implanted to different target, namely muscle, C5 segment of the spinal cord, subcutaneous fat or having a ligation. Animals were allowed to survive for 4 or 8 weeks. After so, the numbers of motoneurons with axonal regeneration and NOS expression were studied. Results shown that there was no significance difference on axonal regeneration with different surgical method at 8 weeks and so we suggested the use of contact method for its ease and lower risk. Ligation to the distal end of the nerve initially may be beneficial but a proper innervation target was required for latter period of time. Moreover, NOS expression was only observed in neurons without axonal regeneration while all regenerating neurons had no NOS expression, and was unrelated to the innervation target. This suggested that down-regulation of NOS expression is more related to presence of PNG. DOI: 10.5353/th_b3984903 Subjects: Motor neurons - Transplantation Nervous system - Regeneration