采用仿生神经再生环境组织工程技术实验治疗大鼠脊髓损伤研究

The spinal cord injury (SCI) is a severe disorder, which causes a permanent loss of neurons in the related CNS area and paraplegia in patients. It has been not found an effective approach so far to restore such a grave disease, especially in its chronic phase. Recently, the techniques of tissue engineering and stem cells have been used for experimental restoration of the SCI and provided an inviting prospective. Our previous studies have also confirmed the usefulness of tissue engineering for neural repair in the CNS. The effects by such approaches are limited however, since the scaffolds provided so far do not seem to mimic unique structure of the spinal cord perfectly and support a micro-environment or niche for neural regeneration in the CNS..The aim of present study therefore is first to improve dramatically the artificial scaffolds, by confering a similar structure of the spinal cord and linking several molecules upon the artificial materials for tissue engineering. The molecules chosed are specially helpful to create a good micro-environment for neural regeneration. The second aim of this study is to see the effects of transplantation of newly created scaffolds, combined with cultured olfactory ensheathing cells (OECs), into the injured area of rat models with a hemisection of the spinal cord. .The hyaluronic acid hydrogel modified with anti-NgR antibody and PLL are prepared for scaffolds and structured in a pattern with longitudinal multiple-channels and multi-porous. The gel will be added with poly (actic glycolic acid) ( PLGA) microspheres bringing the molecules of VEGF, NT3 and NGF, for promoting angiogenisis, cellular survival and axon regrowth. This novel scaffolds with bio-activity together with OECs will then be grafted into the injury area of rat spinal cord. The changes of angiogenesis, axon regenerations, circuit reconstructions and synaptic connections will all be tested inside and outside of the graft. The functional recovery of the animal will also be assessed. The present study may develop a new approach to restore certain injured spinal cord by creating a more suitable micro-environment for neural regeneration in the CNS and be also helpful for better understanding the mechanism of rehabilitation of the spinal cord after a severe injury.

各种原因引起的脊髓损伤常造成截瘫、又无有效治疗手段，属于全世界医务和神经科学界关注的重大问题。目前用组织工程和干细胞技术试验修复脊髓损伤则是国内外诸多研究者探索的热点，但又因支架材料不能适合脊髓结构、不能营造脊髓神经再生复杂微环境而影响疗效。为此，本课题拟在以往工作基础上，采用具有再生活性、仿生脊髓结构的组织工程支架联合嗅鞘细胞移植对大鼠脊髓半横断模型进行试验性治疗。材料采用经NgR抗体和PLL修饰的透明质酸水凝胶，其中包埋聚乳酸聚乙醇酸共聚物微球缓释VEGF、NT3、NGF因子，仿生脊髓解剖结构制成模拟神经再生微环境的多功效支架，携带嗅鞘细胞植入大鼠脊髓损伤区，观察移植物和脊髓组织微血管重建、细胞再生、神经纤维生长、髓鞘化和突触联系重建状况，检测动物行为学的改善程度。希望通过本研究能提供一个更符合脊髓组织再生、纤维联系重建微环境并能改善脊髓功能的新方法，藉此丰富脊髓损伤修复理论认识。

各种原因引起的严重脊髓损伤常造成不同程度瘫痪，临床现无有效疗法，是医学亟待解决的重大难题。目前用组织工程和干细胞技术试验修复脊髓损伤是研究热点，但因支架材料不能适合脊髓精细结构、未能营造神经再生复杂微环境而影响疗效。为此，本项目研究制备了具有再生活性、仿生脊髓结构的组织工程支架联合细胞移植对大鼠脊髓半横断模型进行试验性治疗。支架采用经NgR抗体和PLL修饰的透明质酸水凝胶，包埋聚乳酸聚乙醇酸共聚物微球缓释VEGF、BDNF因子，并仿生脊髓解剖结构，制成结构和功能模拟神经再生微环境的多功效支架，植入大鼠脊髓损伤区，促进了脊髓组织微血管重建、神经细胞存活、神经纤维再生、髓鞘化和突触联系重建，明显改善动物行为学。本项研究的成果提供了一个更符合脊髓组织再生微环境、能改善脊髓功能的新材料，丰富了脊髓损伤修复理论，提供了脊髓损伤治疗的新方法。

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