周围神经修复与再生研究进展

周围神经修复与再生基础研究涉及到诸多因素:神经营养因子对神经元胞体的保护;神经再生微环境的重建;桥接物与神经缺损的修复与再生;神经末梢及效应器的再生与重建等。为进一步探讨周围神经的修复与再生,现综述如下。 一、神经营养因子对损伤神经元胞体的保护 周围神经损伤虽然局限于神经元轴突的部位,但作为基础研究应分为对神经元胞体、神经轴突、神经末梢和效应器四个     

巨噬细胞在周围神经损伤和再生中的行为及其作用

巨噬细胞在周围神经损伤和再生中的行为及其作用王国英，胡耀民，钟世镇（第一军医大学解剖学教研室，广州５１０５１５）对周围神经中非神经元细胞在神经损伤和再生过程中的作用，人们研究得最多的就是雪旺氏细胞；而对巨噬细胞这一主要的、但常常被忽视的细胞成分，认识...     

周围神经再生修复有关的研究

周围神经损伤后,对治疗的最主要要求,就是提高功能恢复率。但迄今为止,周围神经断裂性损伤后的肢体功能恢复率并不如人意,伤残率的比例仍较高。近年来结合临床进行的研究,重点放在周围神经再生修复方面。现将与周围神经有关的形态学基础研究部分,简介如下。一、神经缝合术式有关的研究神经断裂性损伤,传统用的是神经外膜缝合法。此种术式由于再生神经纤维,易受阻于神经干内的结缔组织或功能束对接错位,术后功能恢复优良率较低,仅达50～60％。Smith(1964)借助显镜外科的技术,创用了神经束膜缝合术,提高了神经断端精确度,已将术     

周围神经再生微环境的研究进展

周围神经再生的微环境(Microenvirome-nt)是近十年来出现的新概念,指的是周围神经损伤修复后,能否成功地再生主要取决于是否具有适合其生长的微环境条件。虽然目前对这种微环境的认识还很不完全,但已了解到微环境中含有多种物质成份,对再生神经的生长和走向起着十分重要的营养和诱导作用。国外近年来对此进行了一系列研究,现将有关问题综述如下。一、微环境的有关概念aguayo曾在实验中将大白鼠的视神经切断,然后桥接一段长30mm的自体坐骨神经,发现近端视神经的再生纤维能够长入周围神经     

周围神经再生中人工再生管道的研究进展

周围神经损伤造成的长段神经缺损的临床修复一直是临床工作中的一个难题。随着对神经再生理论认识的深入 ,应用人工再生管道做桥接物 ,引导再生轴突长向靶器官已取得了一定的进展。本文对各种人工再生管道的特点以及在神经再生中的作用进行了综述     

周围神经再生时重组CNTF对受损神经元 STAT3表达和酪氨酸磷酸化的作用

目的 研究周围神经再生时，重组睫状神经营养因子(CNTF)对受损神经元JAK-STAT途径和酪氨酸磷酸化的作用。方法 用硅管套接切断的成年大鼠坐骨神经，术时在受损神经局部给予重组CNTF，用免疫组织化学ABC法结合计算机图像分析研究STAT3、磷酸化酪氨酸(PTyr)免疫反应阳性物质在L3～5段脊髓前角外侧核和L5脊神经节神经元中的分布和相对含量。结果 与生理盐水组相比，CNTF组脊髓前角外侧核神经元胞核STAT3和胞膜PTyr阳性物质的含量更高，脊神经节神经元胞浆和胞核，PTyr阳性物质的含量更高。结论 重组CNTF能激活和强化受损运动神经元的JAK-STAT途径，增强受损神经元的酪氨酸磷酸化。     

靶肌肉注射促红细胞生成素对大鼠周围神经再生的作用

目的探讨靶肌肉注射人重组促红细胞生成素（recombinant human erythropoietin，rh-EP0）对大鼠坐骨神经损伤后神经再生的作用。方法选用健康雄性SD大鼠12只，制备大鼠右侧坐骨神经钳夹损伤模型。实验动物随机分为2组，每组6只，EPO组：靶肌肉注射rh-EPO2500U／kg；对照组：注射同体积的生理盐水。术后第7d、14d、21d观察坐骨神经功能指数（SFI），第21d组织学观察脊髓腰膨大（L4～L6）、夹伤远端坐骨神经、损伤侧腓肠肌组织并作图象分析测定脊髓前角运动神经元数、再生有髓神经纤维数、髓鞘厚度、轴突直径和腓肠肌肌细胞横截面积等指标。结果术后第7d两组SFI无显著性差异，术后第14d、21dEPO组SFI恢复程度明显大于对照组，差别有显著性意义（P〈0．05）；术后第21d损伤侧脊髓前角运动神经元数、再生有髓神经纤维数、髓鞘厚度、轴突直径和腓肠肌肌细胞横截面积等指标，EPO组均优于对照组（P〈0．01，P〈0．05）。结论靶肌肉注射rh-EPO能促进周围神经再生和功能恢复。     

线粒体转运相关蛋白在周围神经再生过程中的作用

线粒体是细胞代谢的能量来源,周围神经损伤后轴突线粒体产生有害的活性氧而不利于周围神经再生.周围神经再生是一个伴随高能量消耗的复杂过程,线粒体在其中发挥重要作用.近十年来,关于线粒体动力学对周围神经轴突及髓鞘再生的作用研究方面取得了较大进展,包括线粒体转运相关蛋白的相关机制和作用靶点的研究,为周围神经再生提供了新思路.     

周围神经趋化性再生研究新进展

周围神经损伤后修复及功能重建一直是临床治疗的难题.现从周围神经趋化性再生的概念,感觉与运动神经元自身差异、远侧端神经、施万细胞、成纤维细胞以及轴突导向因子等方面阐述了目前周围神经趋化性再生的研究进展,为将来开发更好的工程化神经组织,促进神经功能良好的恢复提供基础知识.     

In vivo studies of silk based gold nano-composite conduits for functional peripheral nerve regeneration

We report a novel silk-gold nanocomposite based nerve conduit successfully tested in a neurotmesis grade sciatic nerve injury model in rats over a period of eighteen months. The conduit was fabricated by adsorbing gold nanoparticles onto silk fibres and transforming them into a nanocomposite sheet by electrospinning which is finally given a tubular structure by rolling on a stainless steel mandrel of chosen diameter. The conduits were found to promote adhesion and proliferation of Schwann cells in vitro and did not elicit any toxic or immunogenic responses in vivo. We also report for the first time, the monitoring of muscular regeneration post nerve conduit implantation by recording motor unit potentials (MUPs) through needle electromyogram. Pre-seeding the conduits with Schwann cells enhanced myelination of the regenerated tissue. Histo-morphometric and electrophysiological studies proved that the nanocomposite based conduits pre-seeded with Schwann cells performed best in terms of structural and functional regeneration of severed sciatic nerves. The near normal values of nerve conduction velocity (50 m/sec), compound muscle action potential (29.7 mV) and motor unit potential (133 μV) exhibited by the animals implanted with Schwann cell loaded nerve conduits in the present study are superior to those observed in previous reports with synthetic materials as well as collagen based nerve conduits. Animals in this group were also able to perform complex locomotory activities like stretching and jumping with excellent sciatic function index (SFI) and led a normal life.     

Fibrin conduit supplemented with human mesenchymal stem cells and immunosuppressive treatment enhances regeneration after peripheral nerve injury

To address the need for the development of bioengineered replacement of a nerve graft, a novel two component fibrin glue conduit was combined with human mesenchymal stem cells (MSC) and immunosupressive treatment with cyclosporine A. The effects of MSC on axonal regeneration in the conduit and reaction of activated macrophages were investigated using sciatic nerve injury model. A 10mm gap in the sciatic nerve of a rat was created and repaired either with fibrin glue conduit containing diluted fibrin matrix or fibrin glue conduit containing fibrin matrix with MSC at concentration of 80×10(6) cells/ml. Cells were labeled with PKH26 prior to transplantation. The animals received daily injections of cyclosporine A. After 3 weeks the distance of regeneration and area occupied by regenerating axons and ED1 positives macrophages was measured. MSC survived in the conduit and enhanced axonal regeneration only when transplantation was combined with cyclosporine A treatment. Moreover, addition of cyclosporine A to the conduits with transplanted MSC significantly reduced the ED1 macrophage reaction.     

Recellularized nerve allografts with differentiated mesenchymal stem cells promote peripheral nerve regeneration

Chemical-extracted acellular nerve allografting, containing the natural nerve structure and elementary nerve extracellular matrix (ECM), has been used for peripheral nerve-defect treatment experimentally and clinically. However, functional outcome with acellular nerve allografting decreases with increased size of gap in nerve defects. Cell-based therapy is a good strategy for repairing long nerve defects. Bone-marrow-derived mesenchymal stem cells (BMSCs) and adipose-derived mesenchymal stem cells (ADSCs) can be induced to differentiate into cells with Schwann cell-like properties (BMSC-SCs or ADSC-SCs), which have myelin-forming ability in vitro and secrete trophic nerve growth factors. Here, we aimed to determine whether BMSC-SCs or ADSC-SCs are a promising cell type for enriching acellular grafts in nerve repair. We evaluated axonal regeneration distance by immunofluorescence staining after 2-week implantation. We used functional and histomorphometric analysis to evaluate 3-month regeneration of the novel cell-supplemented tissue-engineered nerve graft used to bridge a 15-mm-long sciatic nerve gap in rats. Introducing BMSC-SCs or ADSC-SCs to the acellular nerve graft promoted sciatic nerve regeneration and functional recovery. Nerve regeneration with BMSC-SCs or ADSC-SCs was comparable to that with autografting and Schwann cells alone and better than that with acellular nerve allografting alone. Differentiated bone-marrow-or adipose-derived MSCs may be a promising cell source for tissue-engineered nerve grafts and promote functional recovery after peripheral nerve injury.     

Neural tissue engineering options for peripheral nerve regeneration

Tissue engineered nerve grafts (TENGs) have emerged as a potential alternative to autologous nerve grafts, the gold standard for peripheral nerve repair. Typically, TENGs are composed of a biomaterial-based template that incorporates biochemical cues. A number of TENGs have been used experimentally to bridge long peripheral nerve gaps in various animal models, where the desired outcome is nerve tissue regeneration and functional recovery. So far, the translation of TENGs to the clinic for use in humans has met with a certain degree of success. In order to optimize the TENG design and further approach the matching of TENGs with autologous nerve grafts, many new cues, beyond the traditional ones, will have to be integrated into TENGs. Furthermore, there is a strong requirement for monitoring the real-time dynamic information related to the construction of TENGs. The aim of this opinion paper is to specifically and critically describe the latest advances in the field of neural tissue engineering for peripheral nerve regeneration. Here we delineate new attempts in the design of template (or scaffold) materials, especially in the context of biocompatibility, the choice and handling of support cells, and growth factor release systems. We further discuss the significance of RNAi for peripheral nerve regeneration, anticipate the potential application of RNAi reagents for TENGs, and speculate on the possible contributions of additional elements, including angiogenesis, electrical stimulation, molecular inflammatory mediators, bioactive peptides, antioxidant reagents, and cultured biological constructs, to TENGs. Finally, we consider that a diverse array of physicochemical and biological cues must be orchestrated within a TENG to create a self-consistent coordinated system with a close proximity to the regenerative microenvironment of the peripheral nervous system.     

The promotion of peripheral nerve regeneration by chitooligosaccharides in the rat nerve crush injury model

Chitooligosaccharides (COSs), the biodegradation product of chitosan, have shown many biological functions. In this study, we examined the possible benefits of treatment with COSs (M.W. 800) on regeneration of rat crushed sciatic nerves. The rats with sciatic nerve crush injury were administered intraperitoneally daily with 3 or 6 mg/kg body weight of COSs over a 3-week period. During and at the end of COSs treatment, a series of functional and histological examinations, including the measurement of withdrawal reflex latency (WRL) values, walking track analysis, electrophysiological assessments, morphometric analysis of gastrocnemius muscle, as well as immunohistochemistry and electromicroscopy to regenerated sciatic nerves, were performed to evaluate the therapeutic outcomes of COSs. The experimental data demonstrated that COSs promoted peripheral nerve regeneration with the desired functional recovery in the rat sciatic nerve crush injury model. This study raises a possibility of developing COSs as a potential neuroprotective agent for peripheral nerve repair applications.     

bFGF对同种异体神经移植后周围神经再生的影响

目的 :探讨bFGF对同种异体神经移植后周围神经再生的影响。方法 :将反复冻融的大鼠神经移植于另一大鼠的坐骨神经 ,实验组注射bFGF 1 0 0u/d共 1 0d ,对照组注射生理盐水 1 0d。术后大鼠存活 1 2周 ,光镜下用体视学方法测试再生神经纤维的面数密度 (NA)、面积密度 (AA)、横切面面积 (AE)、脊髓前角运动细胞和脊神经节细胞的体密度 (VV)、数密度 (NV)。结果 :两组均可见再生神经纤维长入异体移植神经并向远段延伸。实验组再生神经纤维的NA、AA、脊髓前角运动细胞和脊神经节细胞的VV、NV 与对照组的比较 ,有显著性差异。结论 :bFGF能促进周围神经再生 ,对脊髓前角运动细胞和脊神经节细胞的存活有保护作用。     

Conductive PPY/PDLLA conduit for peripheral nerve regeneration

The significant drawbacks and lack of success associated with current methods to treat critically sized nerve defects have led to increased interest in neural tissue engineering. Conducting polymers show great promise due to their electrical properties, and in the case of polypyrrole (PPY), its cell compatibility as well. Thus, the goal of this study is to synthesize a conducting composite nerve conduit with PPY and poly(d, l-lactic acid) (PDLLA), assess its ability to support the differentiation of rat pheochromocytoma 12 (PC12) cells in vitro, and determine its ability to promote nerve regeneration in vivo. Different amounts of PPY (5%, 10%, and 15%) are used to synthesize the conduits resulting in different conductivities (5.65, 10.40, and 15.56 ms/cm, respectively). When PC12 cells are seeded on these conduits and stimulated with 100 mV for 2 h, there is a marked increase in both the percentage of neurite-bearing cells and the median neurite length as the content of PPY increased. More importantly, when the PPY/PDLLA nerve conduit was used to repair a rat sciatic nerve defect it performed similarly to the gold standard autologous graft. These promising results illustrate the potential that this PPY/PDLLA conducting composite conduit has for neural tissue engineering.     

MicroRNA和雪旺细胞自噬与周围神经再生修复的研究进展

正周围神经损伤会使神经支配区域的运动、感觉机能下降和缺失,严重影响生产和生活质量。现代显微外科技术的应用已大大提高了修复效果,但由于周围神经的特殊结构和功能,目前的修复技术对于神经功能的恢复效果仍然有限,这引起了研究者们对于周围神经损伤后再生修复机制的探索。周围神经损伤后,损伤处残存雪旺细胞(Schwann cells)的数量和增殖分化能力是影响神经再生修复的关键因素[1]。在周围神经损伤后的雪旺细胞内发现大量溶     

Development and evaluation of silk fibroin-based nerve grafts used for peripheral nerve regeneration

Silk fibroin (SF), derived from natural silk long used as a textile material, has recently become an important biomaterial for tissue engineering applications. We have previously reported on good in vitro biocompatibility of SF fibers with peripheral nerve tissues and cells. In the present study, we developed a novel biomimetic design of the SF-based nerve graft (SF graft) which was composed of a SF-nerve guidance conduit (NGC) inserted with oriented SF filaments. The SF-NGC prepared via well-established procedures exhibits an eggshell-like microstructure that is responsible for its superior mechanical and permeable properties beneficial to nerve regeneration. The SF graft was used for bridge implantation across a 10-mm long sciatic nerve defect in rats, and the outcome of peripheral nerve repair at 6 months post-implantation was evaluated by a combination of electrophysiological assessment, FluoroGold retrograde tracing and histological investigation. The examined functional and morphological parameters show that SF grafts could promote peripheral nerve regeneration with effects approaching those elicited by nerve autografts which are generally considered as the gold standard for treating large peripheral nerve defects, thus raising a potential possibility of using these newly developed nerve grafts as a promising alternative to nerve autografts.