神经干细胞与透明质酸水凝胶材料生物相容性的研究

目的:评价神经干细胞与改性透明质酸水凝胶支架新材料的生物相容性,研究该透明质酸水凝胶支架作为中枢神经组织工程载体材料的可行性,为用组织工程及干细胞技术治疗中枢神经系统损伤提供基础。方法:以冷冻干燥法制备透明质酸水凝胶材料支架,通过化学接枝法将抗Nogo受体抗体(Anti-NogoR)和多聚赖氨酸(poly-l-lysine,PLL)分子接枝到水凝胶上对其改性,制成新的支架材料。体外培养胚胎13.5d大鼠前脑泡神经干细胞.将神经干细胞与生物支架共培养,通过扫描电镜观察透明质酸水凝胶的内部结构及神经干细胞在支架材料上的粘附与生长情况,通过细胞免疫组织化学技术观察神经干细胞在透明质酸水凝胶材料上的存活与分化情况。结果:制备的透明质酸水凝胶材料具有疏松的三维多孔结构,神经干细胞在支架材料上能够粘附并且有突起长出,生长良好。神经干细胞在支架材料上能够分化。结论:神经干细胞与经过改性的透明质酸水凝胶新材料有很好的生物相容性,能够在材料上存活分化。该新透明质酸水凝胶材料有望作为修复中枢神经损伤的组织工程载体。     

缓释血管内皮生长因子的透明质酸水凝胶对大鼠脑损伤的修复作用

目的:探讨缓释血管内皮生长因子(VEGF)的透明质酸(HA)水凝胶对脑损伤大鼠的修复效果。方法:制备HA水凝胶并在其中添加包封VEGF的聚乳酸聚乙醇酸共聚物(PLGA)微球,形成可缓释VEGF的HA水凝胶复合支架。选用成年SD大鼠制备脑损伤模型,随机分为3组:将HA复合支架植入大鼠脑损伤区作为实验组(HA+PLGA组);单纯模型组;不添加PLGA微球的HA水凝胶植入作为HA对照组(HA组)。结果:HA水凝胶复合支架呈疏松多孔网状结构,可缓慢释放VEGF至少2周;术后8周大体观察可见HA水凝胶和脑组织整合良好,表面光滑; Nissl染色显示支架材料内有大量神经细胞;免疫荧光染色显示单纯HA支架可减轻脑损伤区胶质瘢痕的形成,缓释VEGF的HA复合支架对胶质瘢痕有更强的抑制作用;半薄切片组织学染色可见复合支架植入区有大量新生的血管,有大量细胞,血管周围可见神经纤维,而在单纯HA移植区血管和细胞较少。结论:缓释VEGF的HA水凝胶可与脑组织较好的整合,抑制胶质瘢痕的形成,诱导血管再生,进而促进大鼠脑损伤后的组织修复。     

壳聚糖水凝胶与星形胶质细胞体外生物相容性评价的实验研究

研究壳聚糖水凝胶材料与星形胶质细胞的体外生物相容性,初步探讨壳聚糖水凝胶作为神经组织工程支架材料的可行性。利用氯化壳聚糖、β-甘油磷酸钠和羟乙基纤维素制备壳聚糖水凝胶,MTT法评价其细胞毒性;体外培养鉴定新生Wistar大鼠脑皮层星形胶质细胞;壳聚糖水凝胶与星形胶质细胞体外共培养,观察星形胶质细胞在材料上的生长;MTT法检测接种后1、35、、7d的细胞增殖度。体外成功制备壳聚糖水凝胶,该材料无细胞毒性;体外分离、培养得到状态良好的星形胶质细胞;体外星形胶质细胞在材料上培养呈星形,生长良好,有分支状突起形成;MTT结果表明,材料-细胞共培养组中的细胞增殖度明显高于单纯细胞组（P〈0.001）。壳聚糖水凝胶与星形胶质细胞在体外具有良好的生物相容性,有望作为神经组织工程支架材料。     

以PirB为靶点治疗中枢神经再生的研究进展

<正>哺乳动物中枢神经损伤后轴突再生、突触可塑性和神经功能恢复存在障碍的主要原因之一是由于中枢神经系统存在抑制神经再生的抑制因子和抑制因子受体。Nogo、髓磷脂相关蛋白(myelin-associated glycoprotein,MAG)和少突胶质细胞髓磷脂糖蛋白(oligodendrocyte myelin glycoprotein,OMgp)三种神经抑制因子通过与神经元细胞膜上的Nogo受体(Nogo receptor,NgR)结合,发挥抑制神经生长的作用[1]。然而,通过基因敲除NgR后,并不能完全有效地促进神经突起     

脊髓康对共培养体系中小胶质细胞吞噬及损伤神经元再生的影响

目的:观察中药复方脊髓康对共培养体系中小胶质细胞吞噬及损伤神经元修复再生的影响。方法:制备脊髓康含药血清,分离、鉴定原代海马神经元、原代小胶质细胞,谷氨酸诱导神经元损伤,含药血清预处理小胶质细胞,建立小胶质细胞/ 损伤神经元共培养体系,采用免疫荧光双重标记法观察混培养24 h 后小胶质细胞对神经元碎片的吞噬作用及96 h 后损伤神经元突起生长情况。结果:混合培养24 h 后,脊髓康含药血清中、高剂量组在吞噬指数及吞噬百分率方面均高于空白组(P<0.05),中剂量组低于脂多糖(Lipopolysaccharide,LPS)组(P<0.05),高剂量组与LPS 组间的差异则无统计学意义(P>0.05)。混合培养96 h 后,脊髓康含药血清中、高剂量组一级突起数量多于空白组(P<0.05),与LPS 组比较差异无统计学意义(P>0.05)。脊髓康中、高剂量组平均突起较空白组长(P<0.05),与LPS 对比,脊髓康中剂量组平均神经突起较短(P<0.05),而高剂量组则平均突起较长(P<0.05)。结论:中药复方脊髓康可能通过促进小胶质细胞吞噬神经元碎片,改善局部微环境,从而促进损伤神经元的修复再生。     

体外培养海马神经元生长过程中Nogo-A分布的变化

目的 探讨Nogo-A在神经元中的表达与神经元发育分化的关系，以推测Nogo-A在中枢神经系统发育分化过程中的意义。方法 采用怀孕18d大鼠胚胎海马神经元体外高密度和低密度培养方法，应用免疫荧光细胞化学染色和Western blot，观察Nogo-A在体外培养的大鼠海马神经元的分布模式及其在不同生长阶段的变化。结果 Nogo-A在海马神经元生长过程中均表达，主要分布在胞浆、胞膜和突起上。神经元突起形成过程中，Nogo-A主要表达于突起的近端，在轴突上随着轴突的伸长逐渐表达于轴突远端和生长锥。Nogo-A在成熟神经元网状的突起上呈串珠样分布。结论 Nogo-A在中枢神经系统中具有不同于抑制作用的其他功能，可能参与神经元突起生长、轴突投射等过程。     

伸长细胞促进共培养皮层神经元生长机制的研究

将皮层神经元与传代培养的伸长细胞(tanycytes,TAS)共培养,并与嗅球成鞘胶质细胞(olfactory ensheathing cells,OEC)、星形胶质细胞(astrocytes,AST)共培养的结果相比较,探讨TAS促进共培养神经元生长的机制。共培养中,按胶质细胞介质不同分五组:TAS、OEC、AST、TAS条件培养液组(TCM)和对照组,分析各组神经元2h贴壁数量和7d后神经元存活总数量和突起总长度的差异。结果显示,胶质细胞介质组和TCM组神经元的生长明显高于对照组(P<0.05);TAS组和OEC组对神经元数量和突起长度的影响无明显差别(P>0.05),并均明显高于AST和TCM组(P<0.05);AST与TCM组相比无明显差别(P>0.05)。提示传代培养的TAS与OEC一样都可明显促进皮层神经元的生长;TAS通过接触粘附作用及成鞘作用促进神经元的生长。     

透明质酸修饰的壳聚糖复合支架用于神经组织工程可行性研究

目的探索壳聚糖复合支架经透明质酸（HA）及多聚赖氨酸（PLL）修饰后,神经元在体外复合支架黏附情况,以及将不同复合支架植入鼠脑,观察支架对大鼠脑组织炎症反应、胶质纤维表达的差异。方法孔隙为（70.32±15.33）μm壳聚糖复合支架分别用质量浓度0.05mg/mLHA和质量浓度2mg/mLPLL进行表面涂镀法修饰,继而在上述两组及未修饰复合支架上进行小鼠神经细胞培养,1d后对支架细胞固定行扫描电子显微镜形态学观察,记录两组各30例支架高倍视野下细胞黏附数量;另将复合支架植入大鼠脑皮层损伤区,术后不同时间点分别取脑组织支架行苏木精-伊红染色、免疫组织化学观察炎性细胞及胶质纤维的表达情况。数据用SAS9.1.3统计软件处理,P〈0.05为差异有统计学意义。结果 HA修饰的壳聚糖复合支架上细胞黏附较多[扫描电子显微镜,×1700,（24.9±4.5）/高倍镜],而经PLL修饰的壳聚糖复合支架上细胞黏附相对较少[扫描电子显微镜,×1700,（19.2±3.2）/高倍镜],未修饰支架上细胞碎片较多,并且细胞聚集,细胞总数少;在体内用HA修饰的壳聚糖复合支架组与其他组相比,支架周围炎症反应轻、支架周围胶质纤维酸性蛋白（GFAP）阳性细胞数少。所获得数据分析后差异均有显著统计学意义（P〈0.01）。结论 HA修饰的壳聚糖复合支架能够提高体外神经元黏附,并且在体内观察炎性细胞,胶质纤维表达均优越于PLL修饰的壳聚糖复合支架、单纯壳聚糖复合支架。HA修饰的壳聚糖复合支架在神经组织工程应用中更具有研发前景。     

季铵盐壳聚糖三维支架复合GNDF载间充质干细胞向神经样细胞分化

背景：壳聚糖类水凝胶因其良好的生物相容性、可降解性及对药物的缓释作用,作为支架材料近年来在组织损伤修复领域逐渐成为研究热点。 目的：探索大鼠骨髓间充质干细胞在季铵盐壳聚糖温敏凝胶支架上生长、向神经样细胞定向分化的可行性,为治疗神经系统损伤寻找理想的组织工程材料。 方法：季铵盐壳聚糖与β-甘油磷酸钠复合制成温敏凝胶,扫描电镜观察凝胶的三维结构,MTT法评价凝胶浸提液对骨髓间充质干细胞活力的影响;将牛血清白蛋白加载于凝胶支架,紫外光谱吸收法分析凝胶支架对牛血清白蛋白的缓释效果。接种大鼠骨髓间充质干细胞于凝胶支架,扫描电镜观察在支架缓释胶质细胞源性神经营养因子作用下,骨髓间充质干细胞的生长、分化情况,免疫荧光技术检测神经元烯醇化酶的表达。 结果与结论：季铵盐化壳聚糖与甘油磷酸钠复合所得凝胶支架,其多孔性特点明显,有温敏特性,对蛋白的缓释效果良好,承载大鼠骨髓间充质干细胞后,对其增殖无明显不利影响。在凝胶支架缓释的胶质细胞源性神经营养因子作用下,骨髓间充质干细胞呈现神经样细胞形态,表达神经元特异性标记物神经元烯醇化酶。说明季铵盐壳聚糖温敏凝胶对胶质细胞源性神经营养因子的缓释效果良好,其凝胶支架具有多孔径、良好生物相容性特点,可承载大鼠骨髓间充质干细胞体外生长和向神经元定向分化。     

新型钛基溶胶凝胶涂层的细胞相容性研究

目的 通过对涂层的表面结构及其细胞相容性的研究,对新型的钛基溶胶凝胶HA涂层技术进行评价.方法 在纯钛材料表面制备新型的溶胶凝胶HA涂层,采用SEM对涂层表面特征进行测试.体外成骨细胞(MC-3T3)培养测试涂层的细胞相容性,并将钛基HA溶胶凝胶涂层的细胞相容性与传统的钛基等离子喷涂HA涂层做比较.结果 经过水热处理的钛基涂层表面为均一的晶体颗粒表面,细胞学实验发现与等离子HA涂层相比较,水热处理溶胶凝胶表面增强了细胞粘附作用,具有较好的成骨细胞粘附(P＜0.05).结论 本实验结果提示这种新型的水热处理钛基HA溶胶凝胶表面具有良好的成骨细胞粘附特性,因而有待于作进一步研究.     

Three-dimensional nanofibrillar surfaces covalently modified with tenascin-C-derived peptides enhance neuronal growth in vitro

Current methods to promote growth of cultured neurons use two-dimensional (2D) glass or polystyrene surfaces coated with a charged molecule (e.g. poly-L-lysine (PLL)) or an isolated extracellular matrix (ECM) protein (e.g. laminin-1). However, these 2D surfaces represent a poor topological approximation of the three-dimensional (3D) architecture of the assembled ECM that regulates neuronal growth in vivo. Here we report on the development of a new 3D synthetic nanofibrillar surface for the culture of neurons. This nanofibrillar surface is composed of polyamide nanofibers whose organization mimics the porosity and geometry of the ECM. Neuronal adhesion and neurite outgrowth from cerebellar granule, cerebral cortical, hippocampal, motor, and dorsal root ganglion neurons were similar on nanofibers and PLL-coated glass coverslips; however, neurite generation was increased. Moreover, covalent modification of the nanofibers with neuroactive peptides derived from human tenascin-C significantly enhanced the ability of the nanofibers to facilitate neuronal attachment, neurite generation, and neurite extension in vitro. Hence the 3D nanofibrillar surface provides a physically and chemically stabile cell culture surface for neurons and, potentially, an exciting new opportunity for the development of peptide-modified matrices for use in strategies designed to encourage axonal regrowth following central nervous system injury.     

Novel soft alginate hydrogel strongly supports neurite growth and protects neurons against oxidative stress

Neural tissue engineering focuses on development of biomaterials that could support regeneration of neurons after trauma as well as injury caused by degenerative diseases. In this work we describe novel soft alginate hydrogels, which provide an adhesive matrix for rat and human neurons and facilitate neurite outgrowth. Only soft hydrogels, prepared with sub-stoichiometric concentrations of Ca2?, Ba2?, and Sr2? cations by cross-linking with no >10% of all potentially available gelation sites in alginate, facilitated rapid and abundant neurite outgrowth in primary neuronal monolayer cultures, neural spheroids, and neurons derived from rat and human neural stem cells. To support neurite growth, hydrogels did not require modification by any extracellular matrix components and were prepared from high as well as low viscous alginates of different origin. In addition, neurons cultured on soft hydrogels were resistant to oxidative stress injury induced by hydrogen peroxide. These findings, which apply both to rat and human neurons, go beyond the well-described role of alginates as inert materials for cell encapsulation. Such soft alginate hydrogels may be useful for the preparation of pharmaceutical compositions for prophylaxis and treatment of neurodegenerative disorders, for promoting neuronal regeneration in the peripheral and central nervous system and for neural tissue engineering applications.     

Enhancing the neuronal interaction on fluoropolymer surfaces with mixed peptides or spacer group linkers

Embryonic hippocampal neurons cultured on surface modified fluoropolymers showed enhanced interaction and neurite extension. Poly(tetrafluoroethylene-co-hexafluoropropylene) (FEP) film surfaces were aminated by reaction with a UV-activated mercury ammonia system yielding FEP-[N/O]. Laminin-derived cell-adhesive peptides (YIGSR and IKVAV) were coupled to FEP surface functional groups using tresyl chloride activation. Embryonic (E18) hippocampal neurons were cultured in serum-free medium for up to 1 week on FEP film surfaces that were modified with either one or both of GYIGSR and SIKVAV or GGGGGGYIGSR and compared to control surfaces of FEP-[N/O] and poly(L-lysine)/laminin-coated tissue culture polystyrene. Neuron-surface interactions were analyzed over time in terms of neurite outgrowth (number and length of neurites), cell adhesion and viability. Neurite outgrowth and adhesion were significantly better on peptide-modified surfaces than on either FEP or FEP-[N/O]. Cells on the mixed peptide (GYIGSR/SIKVAV) and the spacer group peptide (GGGGGGYIGSR) surfaces demonstrated similar behavior to those on the positive PLL/laminin control. The specificity of the cell-peptide interaction was demonstrated with a competitive assay where dissociated neurons were incubated in media containing peptides prior to plating. Cell adhesion and neurite outgrowth diminished on all surfaces when hippocampal neurons were pre-incubated with dissolved peptides prior to plating.     

The enhancement of cell adherence and inducement of neurite outgrowth of dorsal root ganglia co-cultured with hyaluronic acid hydrogels modified with Nogo-66 receptor antagonist in vitro

Hyaluronic acid hydrogels modified with polyclonal anti-Nogo-66 receptor antibody were developed in order to promote regeneration in the injured CNS. These modified hydrogels were intended not only to deliver antibodies, but also to serve as a scaffold for neural regeneration following their implantation into injured tissue. Since unmodified hyaluronic acid-hydrogels do not support cell attachment, the gels were modified with polyclonal anti-Nogo-66 receptor with the aim of altering the surface properties of the gels in such a way as to improve neuronal adherence and survival. After evaluating the immobilization efficiency of the system, chicken dorsal root ganglia and dorsal root ganglia cells were planted on the surface of the modified gels to determine cell viability. Dorsal root ganglia were also cultured close to the gels in order to assay the inducement of neurite outgrowth. In dorsal root ganglia and cell viability assay, dorsal root ganglia and neuron cells could adhere to the modified hydrogels and survive well, but it did not happen to unmodified hydrogels. After 72 h, these attached cells were stained positively with immuno-staining for neurofilament. Neurite outgrowth inducement assay showed that the number and length of dorsal root ganglia neurites on the side toward modified hydrogels were significantly more than that on the opposite side (both P<0.01). The results reveal that hyaluronic acid-hydrogels modified with anti-Nogo-66 receptor can support neural cell attachment and survival in vitro. Furthermore, this system can greatly induce neurite outgrowth. The results also indicate that this modified hydrogels have potential to repair injury in the CNS.     

Patterned poly(chlorotrifluoroethylene) guides primary nerve cell adhesion and neurite outgrowth

Central nervous system (CNS) neurons, unlike those of the peripheral nervous system, do not spontaneously regenerate following injury. Recently it has been shown that in the developing CNS, a combination of cell-adhesive and cell-repulsive cues guide growing axons to their targets. We hypothesized that by mimicking these guidance signals, we could guide nerve cell adhesion and neurite outgrowth in vitro. Our objective was to direct primary nerve cell adhesion and neurite outgrowth on poly(chlorotrifluoroethylene) (PCTFE) surfaces by incorporating alternating patterns of cell-adhesive (peptide) and nonadhesive (polyethylene glycol; PEG) regions. PCTFE was surface-modified with lithium PEG-alkoxide, demonstrating the first report of metal-halogen exchange with an alkoxide and PCTFE. Titanium and then gold were sputtered onto PEG-modified films, using a shadow-masking technique that creates alternating patterns on the micrometer scale. PCTFE-Au regions then were modified with one of two cysteine-terminated laminin-derived peptides, C-GYIGSR or C-SIKVAV. Hippocampal neuron cell-surface interactions on homogeneously modified surfaces showed that neuron adhesion was decreased significantly on PEG-modified surfaces and was increased significantly on peptide-modified surfaces. Cell adhesion was greatest on CGYIGSR surfaces while neurite length was greatest on CSIKVAV surfaces and PLL/laminin positive controls, indicating the promise of peptides for enhanced cellular interactions. On patterned surfaces, hippocampal neurons adhered and extended neurites preferentially on peptide regions. By incorporating PEG and peptide molecules on the surface, we were able to simultaneously mimic cell-repulsive and cell-adhesive cues, respectively, and maintain the biopatterning of primary CNS neurons for over 1 week in culture.     

Combined chemical and topographical guidance cues for directing cytoarchitectural polarization in primary neurons

Chemical and topographical cues can be used to guide dissociated neurons into user-defined network geometries on artificial substrates, yet control of neuron polarity (differentiation into axons and dendrites) remains an elusive goal. We developed a dual guidance cue strategy for directing morphological maturity in neurons in vitro using combined chemical and topographical guidance cues on glass substrates. The surface chemistry provides chemical attraction and repulsion for controlling neuron placement and outgrowth, while the topography provides additional surface area for neuron attachment. Poly-l-lysine (PLL) was adsorbed into etched trenches in glass substrates, and an acetone liftoff process was used to produce bifunctional surfaces with a hydrophobic hexamethyldisilazane (HMDS) background and trench patterns of PLL. We examined the cytoarchitectural polarization of dissociated hippocampal pyramidal neurons on guidance cues designed to promote rapid outgrowth of neurites onto continuous line features and delayed neurite outgrowth onto interrupted line features. An optimum distance of approximately 5 μm between the cell body attachment node and the first interrupted line guidance cue led to specific cytoarchitectural polarization of ≥60% of neurons by 3 days of culture in vitro.     

色素上皮源性因子对海马神经元的营养和促突起生长作用

目的:了解色素上皮源性因子(PEDF)对海马神经元的营养和促突起生长作用。方法:采用胚胎大鼠海马神经元体外培养技术,观察不同浓度的PEDF在不同培养条件下神经元的存活和突起生长的影响。结果:在无血清接种,后期培养液含B27条件下,PEDF可提高神经元的存活率,并对存活细胞的活力和突起生长有明显促进作用。但在血清接种,培养液无B27的培养条件下,PEDF不能替代B27维持神经元的生长。而在培养液有B27条件下,PEDF可以促进突起生长并具有一定的剂量依赖性。低浓度(25ng/ml)PEDF相对有利于轴突生长,而高浓度(100ng/ml)PEDF相对有利于树突生长。结论:PEDF对海马神经元具有营养作用,可以促进神经元突起的生长。PEDF的不同浓度可以影响海马神经元树突和轴突的生长。     

The use of a gold nanoparticle-based adjuvant to improve the therapeutic efficacy of hNgR-Fc protein immunization in spinal cord-injured rats

As a common receptor for three myelin associated inhibitors, Nogo-66 receptor (NgR) mediates their inhibitory activities on neurite outgrowth in the adult mammalian central nervous system (CNS). Therapeutic vaccination protocol targeting NgR emulsified with Freund's adjuvant (FA) has been used in spinal cord injury (SCI) models. However, the vaccine emulsified with FA may induce some side effects, which are not suitable for further clinical application. As an adjuvant, gold nanoparticles (GNPs) could stimulate a stronger immune response without producing detectable toxicity and physiological damage than FA. There is, however, uncertainty regarding the efficacy of axon regeneration and neuroprotection in vaccines with GNPs as an adjuvant. In this investigation, a recombinant protein vaccine targeting NgR, human NgR-Fc (hNgR-Fc) fusion protein conjugated with 15?nm GNPs was prepared and its effects on axonal regeneration and functional recovery in spinal cord-injured rats were investigated. The results showed that adult rats immunized with the protein vaccine produced higher titers of anti-NgR antibody than that with FA, and the antisera promoted neurite outgrowth in presence of MAG in?vitro. In a spinal cord dorsal hemisection model, vaccine immunized with GNPs promoted axonal regeneration more effectively than FA, resulted in significant protection from neuronal loss, and improved functional recovery. Thus, as an adjuvant, 15?nm GNPs can effectively boost the immunogenicity of hNgR-Fc protein vaccine, and promote the repair of spinal cord-injured rats. The utilization of GNPs, for clinical considerations, may be a more beneficial supplement than FA to the promising therapeutic vaccination strategy for promoting SCI repair.     

Nogo—A及NgR在墨西哥钝口螈脑组织中的表达及意义

目的探讨勿动蛋白A（Nogo．A）及勿动蛋白受体（NgR）在正常墨西哥钝VI螈及其中脑胆碱能神经元损伤后脑组织中的表达。方法以正常墨西哥钝口螈脑组织和中脑胆碱能神经元损伤后第3、7、14、21天脑组织作为研究对象,采用免疫荧光技术观察正常墨西哥钝口螈脑组织中Nogo—A及NgR的表达;分别用荧光定量PCR和蛋白质印迹法（WB法）检测正常墨西哥钝口螈和损伤组脑组织中Nogo—A及NgR的mRNA含量和蛋白含量的变化。结果正常墨西哥钝口螈脑组织中存在Nogo．A及NgR的表达,在墨西哥钝口螈中脑胆碱能神经元损伤后（注入AF64A）第3天,中脑乙酰胆碱转移酶（CHAT）阳性细胞数明显减少,与正常组比较差异有统计学意义（P〈0．01）,损伤后第7、14、21天均有ChAT、5-溴脱氧尿嘧啶核苷（BrdU）双阳性细胞,且随时间的延长而增加。中脑胆碱能神经元损伤后第3、7、14、21天脑组织中,Nogo．A的mRNA和蛋白水平的表达量与正常组比较差异均无统计学意义;而NgR的mRNA和蛋白水平的表达量均下降,与正常组比较差异有统计学意义（P〈0．05）。结论中枢神经系统损伤后的再生可能与NgR表达量的下降有关。