硫酸软骨素酶ABC在中枢神经系统中促进神经再生的作用

中枢神经系统(CNS)损伤后因胶质瘢痕形成而导致神经元的轴突不能再生,功能恢复不良.胶质瘢痕的重要组分是硫酸软骨素蛋白聚糖(CSPGs),其单独或与其它细胞外基质结合,导致向损伤部位延伸的轴突在胶质瘢痕处停止,而且CSPGs在神经再生时间窗关键期末可降低轴突生长的可塑性.近年研究发现硫酸软骨素酶ABC(chondroi...     

成年大鼠脊髓完全性横断后星形胶质细胞的时空分布及其变化

本研究以成年大鼠脊髓完全性横断模型研究反应性胶质细胞的时空分布和变化。将30只成年Wistar大鼠随机分为5组:正常对照组,T9横断伤1周、2周、4周和8周组,每组6只。利用免疫组织化学方法及图像分析系统对各组动物脊髓内星形胶质细胞的时空分布和变化进行观察和分析。结果显示:脊髓横断组胶质纤维酸性蛋白(GFAP)阳性的星形胶质细胞数目较正常对照组明显增加(P<0.05);距损伤近侧端较距损伤远侧端的GFAP阳性星形胶质细胞数目增加显著(P<0.05);脊髓横断组髓磷脂碱性蛋白(MBP)阳性的少突胶质细胞数目的时间及空间分布与正常对照组相比无统计学差异(P>0.05)。实验结果提示,星形胶质细胞是胶质瘢痕的主要成分,而少突胶质细胞在瘢痕形成过程中并非是反应活跃的成分。     

自组装肽包裹嗅神经鞘细胞抑制脊髓损伤后胶质瘢痕形成并促进轴突再生

目的研究自组装肽包裹嗅神经鞘细胞(OECs)移植对大鼠脊髓损伤(SCI)后轴突再生的影响。方法成年雄性SD大鼠40只,行脊髓T_(10)节段背侧横断术,动物随机分为4组,每组10只。SAP-OECs组于间隙内移植SAP包裹的OECs悬液,SAp、OECs对照组同法分别移植等量SAP及DF12-OECs悬液;单纯全切对照组不做处理。术后2或4周过量麻醉处死动物,脊髓损伤节段连续冰冻矢状切片。行抗GAP-43和GFAP免疫组织化学和免疫荧光双标染色。结果SAP-0ECs组损伤区内有大量GAP-43免疫反应纤维,SAP组相较OECs及单纯半切对照组则可见相当数量GAP-43免疫反应纤维。OECs及单纯半切对照组损伤区周围可见一条致密度的GFAP阳性的反应性星形胶质细胞条带,而SAP组GFAP免疫反应纤维比对照组少,且多于SAP-OECs组。此外激光共聚焦显微镜下观察SAP-OECs组在损伤后4周GAP-43免疫反应纤维能通过位于脊髓损伤区尾端的GFAP阳性区域。结论自组装肽包裹嗅鞘细胞可以抑制脊髓损伤后胶质疤痕形成并促进轴突再生。     

大鼠脊髓损伤后NGF及其受体TrkA在运动神经元及神经胶质细胞表达的变化

为探讨脊髓损伤后运动神经元及神经胶质细胞内神经生长因子(NGF)及其高亲和力受体(TrkA)表达的变化,用改良Allen重击法损伤SCI组动物T12脊髓,按伤后存活时间再将动物分为脊髓损1 d组、2 d组和5 d组。各组动物的脊髓切片经ABC法免疫组织化学染色,用光镜观察TrkA及NGF在脊髓前角运动神经元表达的变化和胶质纤维酸性蛋白(GFAP)及NGF免疫反应阳性胶质细胞的反应性增生程度,并进行图像分析。结果显示:脊髓损伤后前角运动神经元TrkA及NGF的表达随脊髓损伤后动物存活时间的延长逐渐上调;脊髓白质和灰质内尤其是皮质脊髓束内GFAP及NGF阳性胶质细胞明显增生;与此同时,室管膜细胞内亦可见明显的NGF免疫反应产物。上述结果表明,脊髓损伤可刺激脊髓前角运动神经元表达TrkA及NGF,通过自分泌维持受损神经元的存活;损伤部位反应性增生的胶质细胞亦可产生NGF,通过旁分泌作用于脊髓前角运动神经元或皮质脊髓束的轴突末梢,以维持运动神经元的存活及促进皮质脊髓束的再生;适时补充外源性神经营养素或改变损伤局部的微环境将有利于受损脊髓的修复和再生。     

GAP-43治疗大鼠完全性脊髓损伤后GFAP表达的变化及意义

目的:通过制备完全性脊髓损伤(SCI)成年SD大鼠模型,研究生长相关蛋白(GAP-43)治疗大鼠SCI后胶质原纤维酸性蛋白(GFAP)的变化,探讨GAP-43在再生修复中的作用,为临床治疗提供实验参考。方法:咬除T7-T8棘突及相应椎板,用剪刀将脊髓完全横断,制成SCI模型。雌性8周龄SD大鼠75只,随机分为三组:GAP-43抗体组、GAP-43抗原组、对照组,每组25只。使用直接注射法将GAP-43抗原和GAP-43多克隆抗体分别注入抗原组和抗体组的大鼠脊髓的断端,观察各组大鼠肢体功能的恢复情况,用BBB评分法进行不同时段的行为学评分、免疫组化染色及图像分析方法观察GFAP的表达变化,并对其进行相关性分析。结果:对照组大鼠在不同时间段的行为学评分最低,抗原组评分最高;抗原组GFAP阳性细胞显著增多,而抗体组晚期则显著减少。结论:GAP-43可促进星形胶质细胞增生,而GAP-43抗体对星形胶质细胞的增生则表现为抑制作用。本实验结果表明GAP-43对脊髓损伤具有较好的治疗作用。     

电针与骨髓间充质干细胞移植在脊髓损伤修复及再生中的作用

脊髓损伤(spinal cord injury,SCI)后可引起损伤平面以下感觉运动功能丧失,导致患者日常生活不能自理,给家庭和社会带来极大负担.脊髓损伤后的主要病理变化包括大量的神经细胞死亡,轴突退变,弥漫性脱髓鞘,脊髓空洞及胶质瘢痕形成[1],胶质瘢痕在脊髓损伤后形成并逐渐加剧,抑制脊髓损伤的修复[2].这些不可逆的病理过程成为临床治疗脊髓损伤中最棘手的问题.随着干细胞科学的飞速发展,研究发现干细胞移植治疗脊髓损伤具有广阔的应用前景.     

P38 MAPK在大鼠脊髓损伤后胶质瘢痕形成早期对GFAP、vimentin表达的调控作用

目的探讨在大鼠脊髓损伤(SCI)后胶质瘢痕形成早期,p38丝裂原活化蛋白激酶(P38 MAPK)对神经胶质纤维酸性蛋白(GFAP)及波形蛋白(vimentin)表达的影响。方法将大鼠随机分为假手术组(sham group)、模型组(model group)、P38 MAPK特异性激动剂anisomycin组(anisomycin group)和P38 MAPK特异性抑制剂SB203580组(SB203580group)。脊髓夹伤模型制作成功后即分别在损伤区硬脊膜下注射0.9%氯化钠溶液、anisomycin和SB203580各10μL,假手术组只打开椎板暴露脊髓,不做其他处理。于术后第1、3、7及14天利用BBB评分评定大鼠后肢运动功能,用Western blot和免疫荧光标记技术检测GFAP和vimentin表达。结果术后第14天,模型组BBB评分显著低于假手术组(P0.01);SB203580组大鼠BBB评分显著高于模型组(P0.05)但仍低于假手术组(P0.01),而anisomycin组则显著低于模型组(P0.05)。术后第7和14天,模型组GFAP、vimentin的表达显著高于假手术组(P0.01);SB203580组GFAP、vimentin的表达均显著低于模型组(P0.05)但仍高于假手术组(P0.05),而anisomycin组GFAP、vimentin的表达均显著高于模型组(P0.05)。结论 SCI后胶质瘢痕形成早期P38 MAPK可调控GFAP、vimentin的表达,抑制P38 MAPK可降低GFAP、vimentin的表达,减轻大鼠SCI后胶质瘢痕形成,促进神经功能的恢复。     

SHH缓释的脊髓去细胞支架促进大鼠脊髓损伤修复

目的:研究可缓释音猬因子(sonic hedgehog,SHH)的脊髓去细胞支架(acellular spinal cord scaffolds,ASCSs)对大鼠脊髓损伤修复的效果。方法:(1)用物理和化学联合法制备ASCSs,并检测其效果。(2)使用京尼平(genipin,GP)作为交联剂,体外制备缓释SHH的ASCSs(ASCSs-GP-SHH),探究其缓释效果。(3)建立大鼠脊髓损伤(spinal cord injury,SCI)模型,随机分为四组(每组20只):单纯SCI组,ASCSs组,ASCSs-GP组(GP交联的ASCSs),ASCSs-GP-SHH组。术后每周记录BBB评分,评估功能恢复。术后12周取出损伤处脊髓组织,行免疫组化和Western Blot检测损伤处相关蛋白Nestin(巢蛋白),GAP43(生长相关蛋白),MBP(髓磷脂碱性蛋白),NF200(神经丝蛋白),GFAP(胶质纤维酸性蛋白)的表达。结果:(1)物理及化学联法制备ASCSs效果良好;(2)ASCSs-GP-SHH具有良好的缓释SHH的性能;(3)ASCS-GP-SHH组BBB评分从术后到12周较其他组高(P0.05);(4)免疫组化及HE染色结果显示:ASCS-GP-SHH组脊髓横断处有神经元再生。SCI组神经元凋亡明显,纤维瘢痕及空洞大,ASCS-GP组较ASCS组稍好,ASCS组较SCI组稍好;(5)Western Blot结果显示:ASCS-GP-SHH组Nestin,GAP43,MBP,NF200表达高于SCI、ASCS-GP、ASCS组(P0.05),而GFAP低于SCI、ASCS-GP、ASCS组(P0.05)。结论:物理和化学联合制备可以有效的制备ASCSs,ASCSs-GP-SHH缓释效果良好,对大鼠脊髓损伤的修复有明显的促进作用。     

中药髓复康对大鼠脊髓GFAP表达的影响

为了探讨中药制剂髓复康对急性脊髓半横断损伤诱发的星形胶质细胞反应性增生是否具有抑制作用,本实验选用8周龄的清洁级雄性SD大鼠54只,其中48只用于制备T12胸髓右侧半横断损伤模型,并将其随机分为髓复康组(S)和空白对照组(B)。另6只设为正常对照组(N组)。不同时间点取材,采用免疫组织化学法比较各组脊髓损伤区GFAP表达的变化。结果显示,B组在术后3、7、15和30d四个时间点GFAP免疫反应阳性细胞数和GFAP免疫阳性产物的OD值均明显高于N组,术后15d达高峰,各时间点两组之间比较均有显著性差异(P<0.05);在脊髓损伤后3d,S组的GFAP免疫反应细胞数明显少于B组(P<0.05),而GFAP免疫阳性产物的OD值与B组接近。在以后的各个时间点,S组的GFAP免疫反应细胞计数和GFAP免疫阳性产物的OD值都明显低于B组(P<0.05),而高于N组(P<0.05)。研究结果提示,髓复康能减轻大鼠脊髓半横断损伤所诱发的星形胶质细胞反应性增生。     

SHH缓释纤维蛋白支架移植促大鼠脊髓损伤的修复

目的:研究应用可缓释音猬因子(sonic hedgehog,SHH)的纤维蛋白胶(fibrin glue,FG)支架促大鼠脊髓完全横断损伤的修复效果。方法:(1)制作体外缓释SHH的纤维蛋白胶支架模型,探究缓释效果。(2)选用健康的SD大鼠60只,制作大鼠脊髓完全横断模型,随机分为三组:单纯脊髓横断组(SCI),纤维蛋白胶组(FG),音猬因子-支架移植组(F-SHH)。术后每周记录大鼠双后肢功能活动(BBB评分)。术后12周取出脊髓组织,采用免疫组织化学染色和免疫蛋白印迹检测,观察脊髓损伤的近远端神经元存活情况及神经丝蛋白(neurofilament200,NF200),生长再生相关蛋白(growth associated protein-43,GAP43),胶质纤维酸性蛋白(glial fibrillary acidic protein,GFAP)表达情况。结果:(1)载SHH的纤维蛋白胶具有良好的缓释SHH的效果;(2)F-SHH组BBB评分从术后到第十二周较FG、SCI组上升明显(P0.05);(3)免疫组化结果显示:F-SHH组脊髓横断端有一些神经元存活且排列规则,许多神经纤维未完全溃变。SCI组细胞凋亡明显,纤维溃变严重,退变空泡大,FG组较SCI组稍好;(4)Western Blot结果显示:F-SHH组NF200,GAP43相对含量高于FG、SCI组(P0.05),而GFAP相对含量低于FG、SCI组(P0.05)。结论:SHH缓释纤维蛋白支架缓释效果良好,对大鼠脊髓完全横断损伤的修复有明显的促进作用,SHH对于脊髓损伤的修复机理值得进一步研究。     

Partial functional recovery after complete spinal cord transection by combined chondroitinase and clenbuterol treatment

Spinal cord injury not only disrupts axonal tracts but also causes gliotic, fibrotic, and Schwannotic scarring with resulting deposition of chondroitin sulfate proteoglycans (CSPGs) which prevent axonal reconnection and recovery of locomotor function. Here, we determined whether recovery of locomotor function could be promoted after complete transection, by degrading CSPGs enzymatically within the injury site with chondroitinase ABC (chABC) together with treatment with the β₂-adrenoceptor agonist, clenbuterol, a neuroprotective agent which can promote regrowth of lower motoneurons. Partial recovery of locomotor function was observed 8–12 weeks postinjury only after combined chABC and clenbuterol treatment. The recovery of locomotor function coincided with the presence of axons caudal to the injury site arising from neurons of the reticular, vestibular, and red nuclei also only with combined chABC and clenbuterol treatment. Axons myelinated by Schwann cells were most prominent in the transection site in the combined treatment group. Clenbuterol treatment activated cAMP response element binding protein within retrogradely traced neurons which has been associated with axonal regrowth. ChABC treatment decreased scarring due to both CSPG and collagen deposition as well as the gap between intact regions of the spinal cord. ChABC also increased numbers of phagocytic cells which remove myelin debris as well as populations of astrocytes thereby aiding blood–spinal cord barrier reformation. Together the results suggest that chABC and clenbuterol can act synergistically to promote recovery of locomotor function.     

微囊化兔雪旺细胞移植对大鼠损伤脊髓胶质纤维酸性蛋白表达的影响

目的:观察大鼠脊髓损伤后及进行微囊化兔雪旺细胞移植后胶质纤维酸性蛋白(GFAP)表达的变化.方法: 130只成年SD大鼠随机分为微囊组、细胞悬液组、损伤对照组和正常对照组4组,术后3、 7、 14及28d,冰冻切片行免疫组织化学显色观察GFAP表达的变化.结果:大鼠脊髓损伤后3～14d, GFAP阳性细胞数及平均光密度均增加;至第28天时则减少,但仍高于正常组.其中阳性细胞数和平均光密度在第7天开始,微囊组与细胞悬液组、损伤组比较均有明显降低.结论: 微囊化异种雪旺细胞移植能抑制损伤脊髓GFAP的表达,减轻由反应性胶质化所形成的胶质瘢痕.     

汉黄芩苷对大鼠脊髓损伤的修复效果

目的 通过观察不同剂量汉黄芩苷对大鼠脊髓损伤后介导的炎症反应的干预情况,探讨汉黄芩苷对脊髓损伤的影响.方法 建立大鼠脊髓横断损伤模型(n=95),随机分成5组:正常组(N)、生理盐水组(NS)、汉黄芩苷低剂量组(WG12.5)、汉黄芩苷中剂量组(WG25)及汉黄芩苷高剂量组(WG50).采用ELISA检测炎性因子肿瘤坏...     

Robust axonal growth and a blunted macrophage response are associated with impaired functional recovery after spinal cord injury in the MRL/MpJ mouse

Spinal cord injury (SCI) in mammals leads to a robust inflammatory response followed by the formation of a glial and connective tissue scar that comprises a barrier to axonal regeneration. The inbred MRL/MpJ mouse strain exhibits reduced inflammation after peripheral injury and shows true regeneration without tissue scar formation following an ear punch wound. We hypothesized that following SCI, the unique genetic wound healing traits of this strain would result in reduced glial and connective tissue scar formation, increased axonal growth, and improved functional recovery. Adult MRL/MpJ and C57BL/6J mice were subjected to a mid-thoracic spinal contusion and the distribution of axon profiles and selected cellular and extracellular matrix components was compared at 1, 2, 4 and 6 weeks post-injury. Recovery of hind-limb locomotor function was assessed over the same time period. The MRL/MpJ mice exhibited robust axon growth within the lesion, beginning at 4 weeks post-injury. This growth was accompanied by reduced macrophage staining at 1, 2, 4 and 6 weeks post-injury, decreased chondroitin sulfate proteoglycan staining at 1-2 weeks and increased laminin staining throughout the lesion at 2-6 weeks post-injury. Paradoxically, the extent of locomotor recovery was impaired in the MRL/MpJ mice. Close examination of the chronic lesion site revealed evidence of ongoing degeneration both within and surrounding the lesion site. Thus, the regenerative genetic wound healing traits of the MRL/MpJ mice contribute to the evolution of a lesion environment that supports enhanced axon growth after SCI. However, this response occurs at the expense of meaningful functional recovery.     

CTGF siRNA联合电针治疗对大鼠损伤脊髓星形胶质细胞GFAP表达的影响

目的:探讨抗CTGF小干扰RNA(small interferon RNA,siRNA)局部注射联合电针治疗对脊髓损伤(spinal cord injury,SCI)后胶质纤维酸性蛋白(GFAP)表达的影响。方法:将SD大鼠随机分为SCI组、CTGF siR-NA干扰(CTGF)组、CTGF siRNA干扰联合电针(EA+CTGF)组。制作大鼠SCI模型,将含有CTGF siRNA/Invivo-fectamine复合物溶液的明胶海绵移植入CTGF组和EA+CTGF组大鼠的脊髓(T10)损伤断端,SCI组用Invivo-fectamine转染试剂代替。EA+CTGF组在模型制备后每天的固定时间给予电针治疗。各组在3 d、7 d、14 d后分别取材,应用免疫荧光组织化学、Western Blot和逆转录聚合酶链反应(RT-PCR)观察星形胶质细胞的形态、数量和GFAP、GFAP mRNA表达变化。结果:SCI组星形胶质细胞反应性增生、胞体肥大,损伤边缘区形成GFAP强表达的胶质界膜;CTGF siRNA干预后,GFAP表达减弱,胞体减小,GFAP阳性细胞数减少;EA+CTGF组GFAP免疫反应表达明显降低,损伤边缘区GFAP荧光强度与脊髓其它区域基本相同。Western Blot结果显示:与SCI组相比,CTGF组与EA+CTGF组的GFAP均减少,有统计学意义(P<0.05),与CTGF组相比,EA+CTGF组的GFAP减少,有统计学意义(P<0.05);RT-PCR电泳结果表明损伤早期EA+CTGF组GFAP mRNA表达明显低于损伤组并有显著性差异(P<0.01),变化与Western Blot结果是一致的。结论:SCI后,CTGF siRNA联合电针治疗能有效阻止GFAP表达,使胶质反应减轻,有助于神经功能恢复。     

电针刺治疗对脊髓全横断损伤大鼠后肢运动功能的影响

目的：探讨电针刺激大鼠双侧后肢足三里和悬钟、伏兔和三阴交两组穴位对脊髓全横断损伤大鼠后肢运动功能的影响。方法：16只SD大鼠行T11脊髓节段全横断术后，随机分为A、B两组，A组单纯喂养，B组同时予以电针刺治疗；分别于建立模型后第1-8周末，用BBB运动功能评分法评价并比较两组大鼠后肢运动功能恢复程度。结果：A、B两组大鼠术后第1-8周BBB运动功能评分逐渐增高，B组在第1周末和第3-7周末的BBB评分均明显高于A组（P〈0．05）。结论：外周电针治疗能促进脊髓损伤大鼠后肢运动功能的部分恢复。     

PKC mediates inhibitory effects of myelin and chondroitin sulfate proteoglycans on axonal regeneration

Successful axon regeneration in the mammalian central nervous system (CNS) is at least partially compromised due to the inhibitors associated with myelin and glial scar. However, the intracellular signaling mechanisms underlying these inhibitory activities are largely unknown. Here we provide biochemical and functional evidence that conventional isoforms of protein kinase C (PKC) are key components in the signaling pathways that mediate the inhibitory activities of myelin components and chondroitin sulfate proteoglycans (CSPGs), the major class of inhibitors in the glial scar. Both the myelin inhibitors and CSPGs induce PKC activation. Blocking PKC activity pharmacologically and genetically attenuates the ability of CNS myelin and CSPGs to activate Rho and inhibit neurite outgrowth. Intrathecal infusion of a PKC inhibitor, G?6976, into the site of dorsal hemisection promotes regeneration of dorsal column axons across and beyond the lesion site in adult rats. Thus, perturbing PKC activity could represent a therapeutic approach to stimulating axon regeneration after brain and spinal cord injuries.     

Effect of embryonal nerve tissue transplantation on regeneration of dorsal roots of the rat spinal nerves

Using cobalt salts axonal ionophoresis posttraumatic regeneration of TXII dorsal roots nerve fibres in the zone of hemisection in conditions of 14 wks embryo spinal cord transplantation into the zone of trauma of spinal cord. Regro Invasion of dorsal roots nerve fibres into recipients posterior cords and Lissawers tract through the transitional zone "spinal cord--dorsal roots" was observed on posttransplantation d 14-120. It was show that afferent axons predominantly spread in substantia alba and substantia grisea caudal to the level of spinal cord transection with only individual fibres invading rostrad through the neuronal plate. In the transplants neurons were encountered up to d 120 of the observation although transplant neuropil was limited from recipient tissue brain by a glial and connective tissue scar. The influence of embryonal nervous tissue transplantation on intraspinal regeneration of dorsal roots afferents was discussed.     

Extracellular matrix alterations,accelerated leukocyte infiltration and enhanced axonal sprouting after spinal cord hemisection in tenascin-C-deficient mice

The extracellular matrix glycoprotein tenascin-C has been implicated in wound repair and axonal growth. Its role in mammalian spinal cord injury is largely unknown. In vitro it can be both neurite-outgrowth promoting and repellent. To assess its effects on glial reactions, extracellular matrix formation, and axonal regrowth/sprouting in vivo, 20 tenascin-C-deficient and 20 wild type control mice underwent lumbar spinal cord hemisection. One, three, seven and fourteen days post-surgery, cryostat sections of the spinal cord were examined by conventional histology and by immunohistochemistry using antibodies against F4/80 (microglia/macrophage), GFAP (astroglia), neurofilament, fibronectin, laminin and collagen type IV. Fibronectin immunoreactivity was significantly down-regulated in tenascin-C-deficient mice. Moreover, fourteen days after injury, immunodensity of neurofilament-positive fibers was two orders of magnitude higher along the incision edges of tenascin-C-deficient mice as compared to control mice. In addition, lymphocyte infiltration was seen two days earlier in tenascin-C-deficient mice than in control mice and neutrophil infiltration was increased seven days after injury. The increase in thin neurofilament positive fibers in tenascin-C-deficient mice indicates that lack of tenascin-C alters the inflammatory reaction and extracellular matrix composition in a way that penetration of axonal fibers into spinal cord scar tissue may be facilitated.