Effect of controlled delivery of neurotrophin-3 from fibrin on spinal cord injury in a long term model.

The goal of this work was to assess the effect of the controlled delivery of neurotrophin-3 (NT-3) from an affinity-based delivery system in fibrin scaffolds on regeneration following spinal cord injury (SCI). A heparin-based delivery system (HBDS) was used to immobilize NT-3 within fibrin scaffolds via non-covalent interactions. The fibrin scaffolds were implanted in lesions immediately after injury in an adult rat model of SCI (complete ablation of a 2 mm segment of the cord at T9). Delivery of NT-3 was controlled by an affinity-based delivery system that limits drug loss by diffusion and releases the drug via cell-mediated processes. Twelve weeks after injury and treatment, animals treated with fibrin scaffolds and NT-3, with or without the delivery system, did not show functional improvement over saline controls. Substantial cavitation at edges of the lesion was present, and while neuronal fibers were present inside the lesion, traced corticospinal and dorsal sensory tracts did not regenerate into the lesion. Therefore, while previous studies indicate that the controlled delivery of NT-3 from fibrin scaffolds may increase the short term regenerative response, the continued degeneration of the cord, indicative of the severity of the injury, limits the long term regeneration stimulated by this treatment. Chronic or repeated treatments or a less severe injury model may prove useful in assessing the utility of controlled delivery systems for the treatment of spinal cord injury.     

Controlled release of neurotrophin-3 from fibrin gels for spinal cord injury.

The goal of this work was to assess the feasibility of using affinity-based delivery systems to release neurotrophin-3 (NT-3) in a controlled manner from fibrin gels as a therapy for spinal cord injury. A heparin-based delivery system (HBDS) was used to immobilize NT-3 within fibrin gels via non-covalent interactions to slow diffusion-based release of NT-3, thus allowing cell-activated degradation of fibrin to mediate release. The HBDS consists of three components: immobilized linker peptide, heparin and NT-3. The linker peptide contained a Factor XIIIa substrate and was covalently cross-linked to fibrin during polymerization. This immobilized linker peptide sequesters heparin within fibrin gels, and sequestered heparin binds NT-3, preventing its diffusion. Mathematical modeling was performed to examine the effect of heparin concentration on the fraction of NT-3 initially bound to fibrin. In vitro release studies confirmed that heparin concentration modulates diffusion-based release of NT-3. Fibrin gels containing the HBDS and NT-3 stimulated neural outgrowth from chick dorsal root ganglia by up to 54% versus unmodified fibrin, demonstrating that the NT-3 released is biologically active. In a preliminary in vivo study, fibrin gels containing the HBDS and NT-3 showed increased neural fiber density in spinal cord lesions versus unmodified fibrin at 9 days.     

神经营养素-3对大鼠脊髓损伤后caspase-3基因表达的影响

【目的】研究神经营养素-3(NT-3)对大鼠脊髓损伤后caspase-3基因表达的影响,探讨NT-3在脊髓损伤修复中的作用。【方法】SD大鼠80只,分为生理盐水对照组和NT-3组。用RT-PCR分析方法观察两组caspase-3基因的表达情况。【结果】①脊髓损伤后caspase-3基因mRNA转录水平升高;②NT-3组与生理盐水对照组相比caspase-3基因转录水平下降(P<0.05)。【结论】NT-3抑制caspase-3基因的表达,可能是促进神经纤维损伤后再生的一个重要因素。     

骨髓间充质干细胞移植脊髓全横断模型大鼠运动和体感诱发电位的评价

背景：临床常用皮质运动诱发电位和皮质体感诱发电位来分别评价脊髓损伤后运动传导路和感觉传导路的损伤或修复情况。目的：以脊髓诱导电位监测骨髓间充质干细胞移植后急性脊髓完全性损伤大鼠下肢神经功能的变化。方法：选取健康Wistar大鼠50只,分成5组,即生理盐水组、骨髓间充质干细胞移植组、脑源性神经营养因子修饰组、神经营养素3＋骨髓间充质干细胞移植组和假手术组。除假手术组外,其余各组均制作Allen’s脊髓完全性损伤动物模型,造模后各组均行相应治疗。治疗后4,8和12周行大鼠后肢运动功能评分,并于造模后24h,3,7,14d行运动和体感诱发电位检测。结果与结论：运动诱发电位检测结果提示,各治疗组的运动功能均有不同程度的恢复,与生理盐水组间差异均有显著性意义（P〈0.05）,大鼠后肢BBB评分也证实了各治疗组后肢运动功能明显优于生理盐水组（P〈0.05）。提示经脑源性神经营养因子修饰的骨髓间充质干细胞可移植到脊髓损伤处,可改善大鼠的后肢运动,神经营养素3蛋白有可能提高骨髓间充质干细胞在体内的生存率,促进受损脊髓的轴突再生。     

移植自聚合肽纳米纤维材料与RhoA-siRNA复合物修复脊髓损伤

背景:脊髓损伤后RhoA表达增高是神经再生困难的主要原因之一,本课题在前期研究证明自聚合肽纳米纤维材料能较好地促进脊髓损伤后结构与功能修复的基础上,构建了自聚合肽纳米纤维材料与RhoA-siRNA复合材料用于修复脊髓损伤。目的:探讨自聚合肽纳米纤维材料介导siRNA干扰RhoA表达促进脊髓损伤修复。方法:54只昆明小鼠随机数字表法分为4组。假手术组仅作脊髓暴露,其他3组在切除1mm脊髓组织制备全横断脊髓损伤模型后,分别于损伤腔内填充生理盐水、自聚合肽纳米纤维支架或含有RhoA特异性siRNA复合物。通过FAM标记检测siRNA转染效率;免疫组化检测RhoA表达;免疫组化和定量分析检测再生神经纤维;行为学检测评定后肢功能恢复。结果与结论:移植FAM标记的含有RhoA特异性siRNA复合物后,在脊髓内的神经纤维及大脑皮质运动区神经元胞体内均可检测到FAM荧光信号,提示siRNA可从复合材料中释放到组织中并成功导入靶细胞。与SAPNS组和生理盐水组相比,含有RhoA特异性siRNA复合物和自聚合肽纳米纤维支架组可显著降低RhoA在神经元的表达,提高脊髓损伤区内NF阳性神经纤维的密度,促进后肢功能的恢复。结果提示通过自聚合肽纳米纤维支架的介导,含有RhoA特异性siRNA复合物能有效干扰RhoA表达,从而促进脊髓损伤的修复。     

移植自聚合肽纳米纤维材料与RhoA-siRNA复合物修复脊髓损伤

背景：脊髓损伤后RhoA表达增高是神经再生困难的主要原因之一,本课题在前期研究证明自聚合肽纳米纤维材料能较好地促进脊髓损伤后结构与功能修复的基础上,构建了自聚合肽纳米纤维材料与RhoA-siRNA复合材料用于修复脊髓损伤。目的：探讨自聚合肽纳米纤维材料介导siRNA干扰RhoA表达促进脊髓损伤修复。方法：54只昆明小鼠随机数字表法分为4组。假手术组仅作脊髓暴露,其他3组在切除1mm脊髓组织制备全横断脊髓损伤模型后,分别于损伤腔内填充生理盐水、自聚合肽纳米纤维支架或含有RhoA特异性siRNA复合物。通过FAM标记检测siRNA转染效率;免疫组化检测RhoA表达;免疫组化和定量分析检测再生神经纤维;行为学检测评定后肢功能恢复。结果与结论：移植FAM标记的含有RhoA特异性siRNA复合物后,在脊髓内的神经纤维及大脑皮质运动区神经元胞体内均可检测到FAM荧光信号,提示siRNA可从复合材料中释放到组织中并成功导入靶细胞。与SAPNS组和生理盐水组相比,含有RhoA特异性siRNA复合物和自聚合肽纳米纤维支架组可显著降低RhoA在神经元的表达,提高脊髓损伤区内NF阳性神经纤维的密度,促进后肢功能的恢复。结果提示通过自聚合肽纳米纤维支架的介导,含有RhoA特异性siRNA复合物能有效干扰RhoA表达,从而促进脊髓损伤的修复。     

神经营养因子3 壳聚糖支架诱导成年大鼠脑损伤后海马神经网络的形成

目的观察神经营养因子3(NT-3)壳聚糖支架诱导神经突触形成,修复成年大鼠创伤性脑损伤。方法60 只成年雄性Wistar 大鼠平均分为单纯损伤组、单纯壳聚糖支架组和NT-3 壳聚糖支架组,分别于术后3 d、7 d、14 d、28 d 和60 d,通过免疫组织化学方法检测损伤区神经再生。术后30 d 和60 d 应用神经示踪方法与免疫电镜技术观察损伤区内再生的神经突触。结果NT-3壳聚糖支架组海马损伤区内nestin+、微管蛋白β-tubulin-Ⅲ+、微管相关蛋白2 (MAP2)+神经细胞较单纯壳聚糖支架组和单纯损伤组明显增加(P<0.01)。NT-3 壳聚糖支架组在海马损伤区内观察到5-溴脱氧尿嘧啶(BrdU)/MAP2+双阳性新生神经元,并形成突触联系。结论NT-3 壳聚糖支架可激活脑损伤区神经前体细胞增殖,分化为成熟神经元并形成神经突触,参与脑神经网络的重建。     

脊髓重建管对T8损伤大鼠后肢运动终板的调节与维持

目的观察大鼠脊髓损伤后及脊髓重建管诱导脊髓再生修复过程中后肢骨骼肌运动终板形态结构与不同类型肌纤维终板区乙酰胆碱酯酶(AChE)的变化情况。方法43只成年Wistar大鼠随机分为脊髓T₈单纯损伤组（Cx组）、脊髓T₈损伤+脊髓重建管移植修复组（CxTp组）和正常对照组（Co组）,术后2周、4周、3个月、6个月、12个月经灌注固定后取出大鼠双下肢腓肠肌、比目鱼肌和趾长伸肌,分别用氯化金染色（压片法）观察运动终板结构形态和Karnovsky-Roots直接法染色检测AChE的变化。结果Cx组和CxTp组大鼠术后运动终板结构形态与AChE活性均发生改变。Cx组终板自术后3个月起发生明显的退行性改变,AChE活性亦呈线性下降;CxTp组终板结构与形态相对稳定,没有退变迹象,术后3个月起AChE 活性显著高于同时间点Cx组。结论大鼠脊髓损伤后,运动终板发生进行性退变,脊髓重建管移植修复可以阻止终板的退行性变,使其向着利于神经康复的方向发生着AChE的复活与结构形态的可塑性变化。     

胶质细胞源性神经营养因子缓释微球及NogoA,ChABC缓释微球联合应用损伤脊髓再生的形态学变化

背景:促进轴突再生的原则是改善抑制再生的环境和提高轴突生长能力,措施主要有轴突生长抑制因子阻滞剂和神经营养因子应用。用可降解微球加载药物是一种在局部提供持续药物释放的方法。目的:探讨胶质细胞源性神经营养因子、NogoA、ChABC缓释微球联合应用促进大鼠损伤脊髓再生病理形态学修复的作用。方法:建立SD大鼠T10脊髓完全横断伤模型,分别在损伤局部给予生理盐水、胶质细胞源性神经营养因子、胶质细胞源性神经营养因子缓释微球、NogoA缓释微球、ChABC缓释微球及3种微球联合治疗,并设立未造模的正常组及假手术组。损伤后10周,每组行四甲基若丹明葡聚糖胺顺行示踪,及神经丝蛋白200、生长相关蛋白43、胶质细胞源性神经营养因子免疫组化检查,并采用免疫组化图像分析系统进行定量分析。结果与结论:胶质细胞源性神经营养因子、NogoA、ChABC缓释微球联合能提高脊髓损伤局部神经丝蛋白200、生长相关蛋白43、胶质纤维酸性蛋白的表达水平,显示局部脊髓再生修复加强,其效果优于单用胶质细胞源性神经营养因子缓释微球。提示,胶质细胞源性神经营养因子缓释微球及NogoA,ChABC缓释微球联合促大鼠损伤脊髓再生修复其效果优于单用胶质细胞源性神经营养因子缓释微球。     

胶质细胞源性神经营养因子缓释微球及NogoA,ChABC缓释微球联合应用损伤脊髓再生的形态学变化

背景：促进轴突再生的原则是改善抑制再生的环境和提高轴突生长能力,措施主要有轴突生长抑制因子阻滞剂和神经营养因子应用。用可降解微球加载药物是一种在局部提供持续药物释放的方法。目的：探讨胶质细胞源性神经营养因子、NogoA、ChABC缓释微球联合应用促进大鼠损伤脊髓再生病理形态学修复的作用。方法：建立SD大鼠T10脊髓完全横断伤模型,分别在损伤局部给予生理盐水、胶质细胞源性神经营养因子、胶质细胞源性神经营养因子缓释微球、NogoA缓释微球、ChABC缓释微球及3种微球联合治疗,并设立未造模的正常组及假手术组。损伤后10周,每组行四甲基若丹明葡聚糖胺顺行示踪,及神经丝蛋白200、生长相关蛋白43、胶质细胞源性神经营养因子免疫组化检查,并采用免疫组化图像分析系统进行定量分析。结果与结论：胶质细胞源性神经营养因子、NogoA、ChABC缓释微球联合能提高脊髓损伤局部神经丝蛋白200、生长相关蛋白43、胶质纤维酸性蛋白的表达水平,显示局部脊髓再生修复加强,其效果优于单用胶质细胞源性神经营养因子缓释微球。提示,胶质细胞源性神经营养因子缓释微球及NogoA,ChABC缓释微球联合促大鼠损伤脊髓再生修复其效果优于单用胶质细胞源性神经营养因子缓释微球。     

Strategies for neurotrophin‐3 and chondroitinase ABC release from freeze‐cast chitosan–alginate nerve‐guidance scaffolds

Freeze casting, or controlled unidirectional solidification, can be used to fabricate chitosan–alginate (C–A) scaffolds with highly aligned porosity that are suitable for use as nerve‐guidance channels. To augment the guidance of growth across a spinal cord injury lesion, these scaffolds are now evaluated in vitro to assess their ability to release neurotrophin‐3 (NT‐3) and chondroitinase ABC (chABC) in a controlled manner. Protein‐loaded microcapsules were incorporated into C–A scaffolds prior to freeze casting without affecting the original scaffold architecture. In vitro protein release was not significantly different when comparing protein loaded directly into the scaffolds with release from scaffolds containing incorporated microcapsules. NT‐3 was released from the C–A scaffolds for 8 weeks in vitro, while chABC was released for up to 7 weeks. Low total percentages of protein released from the scaffolds over this time period were attributed to limitation of diffusion by the interpenetrating polymer network matrix of the scaffold walls. NT‐3 and chABC released from the scaffolds retained bioactivity, as determined by a neurite outgrowth assay, and the promotion of neurite growth across an inhibitory barrier of chondroitin sulphate proteoglycans. This demonstrates the potential of these multifunctional scaffolds for enhancing axonal regeneration through growth‐inhibiting glial scars via the sustained release of chABC and NT‐3. Copyright © 2014 John Wiley & Sons, Ltd.     

骨髓基质细胞移植促进脊髓全横断损伤区神经元轴突的再生变化

背景:近年来,部分学者证明骨髓基质细胞移植可促进轴突再生,改善脊髓损伤引起的运动功能障碍,但目前关于移植骨髓基质细胞如何促进轴突再生,移植细胞与再生轴突的关系尚不清楚.目的:通过免疫荧光组织化学和免疫电镜的方法,探讨移植骨髓基质细胞促进脊髓全横断损伤区轴突再生的机制.设计、时间及地点:随机对照动物实验,细胞学体内观察,于2006-03/2007-06在新加坡国立大学解剖系完成.材料:清洁级Wistar新生大鼠1只,用于骨髓基质细胞培养.清洁级成年雌性Wistar大鼠36只,无菌条件下显露、切断脊髓T_(10),制备脊髓全横断损伤模型.方法:通过传代法培养、纯化骨髓基质细胞.36只成年Wistar雌性大鼠随机投币法分为移植组和对照组,每组18只.移植组大鼠脊髓全横断损伤9 d后以1×10~(11)L~(-1)的密度移植骨髓基质细胞,缺损区5μL,损伤区上、下1 mm处各2.5 μL,对照组动物在相同部位注射等量DMEM完全培养基,注射速度1 μL/min.主要观察指标:①移植骨髓基质细胞存活、分化情况.②轴突再生情况.③移植组和对照组宿主自身的nestin、NF200、GFAP和CNP阳性细胞在脊髓损伤区存活情况.④内源性CNP阳性细胞和再生纤维关系.结果:骨髓基质细胞移植2周时,脊髓损伤区可见大量CFDA-SE标记的移植细胞,随时间延长,存活的移植细胞数目逐渐降低,考虑脊髓损伤区内大量的0×42阳性吞噬细胞,激活小胶质细胞及空洞可能影响移植细胞的存活.虽然骨髓基质细胞数目逐渐降低,骨髓基质细胞移植可促进损伤区轴突的再生,而且还可促进宿主自身的nestin、NF200、GFAP和CNP阳性细胞在脊髓损伤区存活.宿主自身CNP和许旺细胞促进损伤轴突的再生和髓鞘形成.结论:移植骨髓基质细胞移植可促进宿主自身CNP和许旺细胞在脊髓损伤区存活,后者具有促进损伤轴突再生和髓鞘形成的作用.     

Local delivery of FTY720 and NSCs on electrospun PLGA scaffolds improves functional recovery after spinal cord injury

Spinal cord injury (SCI) is a common issue in the clinic that causes severe motor and sensory dysfunction below the lesion level. FTY720, also known as fingolimod, has recently been reported to exert a positive effect on the recovery from a spinal cord injury. Through local delivery to the lesion site, FTY720 effectively integrates with biomaterials, and the systemic adverse effects are alleviated. However, the effects of the proper mass ratio of FTY720 in biomaterials on neural stem cell (NSC) proliferation and differentiation, as well as functional recovery after SCI, have not been thoroughly investigated. In our study, we fabricated electrospun poly (lactide-co-glycolide) (PLGA)/FTY720 scaffolds at different mass ratios (0.1%, 1%, and 10%) and characterized these scaffolds. The effects of electrospun PLGA/FTY720 scaffolds on NSC proliferation and differentiation were measured. Then, a rat model of spinal transection was established to investigate the effects of PLGA/FTY720 scaffolds loaded with NSCs. Notably, 1% PLGA/FTY720 scaffolds exerted the best effects on the proliferation and differentiation of NSCs and 10% PLGA/FTY720 was cytotoxic to NSCs. Based on the Basso, Beattie, and Bresnahan (BBB) score, HE staining and immunofluorescence staining, the PLGA/FTY720 scaffold loaded with NSCs effectively promoted the recovery of spinal cord function. Thus, FTY720 properly integrated with electrospun PLGA scaffolds, and electrospun PLGA/FTY720 scaffolds loaded with NSCs may have potential applications for SCI as a nerve implant.

Spinal cord injury (SCI) is a common issue in the clinic that causes severe motor and sensory dysfunction below the lesion level.     

神经生长因子干预大鼠脊髓损伤模型白质轴突计数和运动功能恢复的变化

背景:有实验已证实多种神经营养因子具有促进损伤神经元存活、分化和轴突再生的作用,使损伤后的脊髓组织结构完整性能得到最大的保存。目的:观察神经生长因子对大鼠脊髓损伤后神经再生和运动功能的影响。设计:随机对照观察。单位:华中科技大学同济医学院附属协和医院神经内科。材料:选用30只成年健康雄性Wistar大鼠(同济医学院动物实验中心)。方法:实验于2004-01/2005-01在华中科技大学同济医学院附属协和医院神经内科完成。采用随机抽签法将大鼠分为治疗组和对照组,每组15只。①造模:应用改良Allen’s打击法致伤脊髓。②干预措施:造模后,治疗组大鼠给予蛛网膜下腔注射含1μg神经生长因子的生理盐水0.05mL,1次/d,共3周;对照组大鼠注射等体积的生理盐水,1次/d,共3W。③斜板试验:在造模前和治疗后3d和1,2,3周分别应用改良Rivlin法(斜板试验)测定大鼠运动功能值。④形态学观察:造模后2天和3周,分别取7只治疗组大鼠和8只对照组大鼠进行NF200免疫组织化学检测与轴突计数。主要观察指标:大鼠造模前、治疗后3d及1,2,3周斜板试验结果以及大鼠造模后2d和3周白质区轴突计数。结果:①治疗组大鼠脊髓损伤后斜板试验结果在术后1,2,3周时分别为(45.2±3.2),(51.2±3.8),(53.4±4.6)°,明显高于对照组(37.2±2.8),(42.6±3.5),(44.5±5.6)°,差异有显著性(P<0.05)。②治疗后3周,对照组白质内可见少量、散在不均匀的NF200着色点。治疗组白质内可见大量均匀的NF200着色点。治疗组大鼠脊髓损伤后3W白质内轴突计数明显高于对照组(363.6±34.2,187.5±32.1,P<0.05)。结论:神经生长因子对脊髓损伤后的神经再生有一定的促进作用,并有助于功能恢复。     

人发角蛋白植入大鼠损伤脊髓部位的电镜观察

目的:脊髓外伤后的继发性病理改变,是影响脊髓神经组织再生修复的重要因素。采用人发角蛋白(humanhairkeratin,HHK)植入脊髓损伤(spinalcordinjury,SCI)部位,以期达到减轻继发性损害,诱导和促进损伤脊髓组织的再生。方法:采用改制Ⅱ型纽约大学(NewYorkUniversity,NYU)装置,在建立大鼠脊髓损伤模型基础上,将经过特殊处理后能在体内降解的HHK植入大鼠损伤脊髓部位,对植入后1,4,12,26周的损伤脊髓组织进行电镜观察。结果:第1周为急性炎症时期,HHK周围结构紊乱,集聚大量的炎症细胞,灰质出现坏死;第4周时,炎症细胞减少,巨噬细胞吞噬髓鞘,胶质细胞增生;第12周时,多核巨噬细胞出现在HHK周围,HHK开始崩解,崩解物被多核巨细胞所吞噬;第26周时,神经轴突沿HHK间隙排列生长,灰质中神经元数量增加,HHK周边细胞有序生长。结论:植入的人发角蛋白具有诱导神经胶质细胞增生,阻止脊髓空洞的形成,从而减轻了脊髓损伤组织的继发性伤害的程度,改善了神经元再生的外环境,并可以桥接诱导神经轴突定向再生的作用。     

Is the recovery of stepping following spinal cord injury mediated by modifying existing neural pathways or by generating new pathways? A perspective.

The recovery of stepping ability following a spinal cord injury may be achieved by restoring anatomical connectivity within the spinal cord. However, studies of locomotor recovery in animals with complete spinal cord transection suggest that the adult mammalian spinal cord can acquire the ability to generate stepping after all descending input is eliminated and in the absence of neuronal regeneration. Moreover, rehabilitative gait training has been shown to play a crucial role in teaching existing spinal pathways to generate locomotion and appropriately respond to sensory feedback. This brief review presents evidence that neural networks in the mammalian spinal cord can be modulated pharmacologically and/or with task-specific behavioral training to generate weight-bearing stepping after a spinal injury. Further, the role that spinal learning can play in the management of humans with spinal cord injury is discussed in relation to interventions that are designed primarily to enhance neuronal regeneration.     

脊髓损伤大鼠远端神经元及骨骼肌的变化

背景：目前针对脊髓损伤病灶的研究较多,而对脊髓损伤后远端神经、肌肉及运动终板三者形态结构实时变化观察和研究的文献很少。目的：观察大鼠脊髓损伤后远端肢体神经、运动终板和骨骼肌随时间推移形态学变化的自然病程。方法：将50只雌性SD大鼠随机分为对照组5只（不做处理）、假手术组10只和脊髓损伤组35只,假手术组行单纯椎板切除术,脊髓损伤组在椎板切除基础上,用横断法制成T10完全脊髓损伤模型,然后在第1,2,4,12,24周分别观察3组大鼠坐骨神经-运动终板-内侧腓肠肌的形态变化。结果与结论：①脊髓损伤组大鼠4周时部分有髓神经纤维髓鞘出现板层分离;24周时崩解髓鞘板层已模糊、碎裂髓鞘增多,薄髓与无髓神经纤维较12周时增多。②脊髓损伤组大鼠运动终板在脊髓损伤12周时明显退变突触结构与较完整突触结构并存;24周时已找不到运动终板。③脊髓损伤组大鼠内侧腓肠肌在脊髓损伤24周时,肌细胞融合,细胞核密集,融合细胞间可见大小不一空隙,结缔组织增生更加明显。结果表明大鼠在完全性横断性脊髓损伤后自然病程中,损伤平面以下周围神经、运动终板、骨骼肌的形态结构均呈规律性改变,损伤后12周时已有显著变化,24周时呈结构毁坏性改变。     

A clonal cell line from immortalized olfactory ensheathing glia promotes functional recovery in the injured spinal cord.

Immortalized cell lines of olfactory ensheathing glia (OEG) that maintain the proregenerative properties of primary cultures provide an unlimited source of OEG for both basic and applied studies. Indeed, one specific immortalized rat OEG clonal line (TEG3) proved to be as good as primary OEG in promoting neuritogenesis and axon regeneration in culture models. Thus, we examined the capacity of TEG3 to promote axonal repair in an animal model of spinal cord injury, dorsal column crush. TEG3 cells can acquire astrocyte-like or Schwann cell-like morphology depending on the conditions under which they are cultured. In the injured spinal cord, prelabeled TEG3 survived for at least 10 weeks after grafting and they integrated into the spinal cord, adopting Schwann cell-like, astrocyte-like, or intermediate morphologies. In TEG3-transplanted animals, sensory projection axons grow into the lesion site and there was robust sprouting/axonal growth of the corticospinal tract, both into and beyond the lesion site, after crushing of the spinal cord-dorsal columns. TEG3-transplanted animals also recovered sensory and motor function in tape removal and beam walking behavioral tests. These data indicate that certain immortalized cell lines derived from a single cell can maintain the regenerative properties of primary OEG.     

Tubular scaffold with microchannels and an H‐shaped lumen loaded with bone marrow stromal cells promotes neuroregeneration and inhibits apoptosis after spinal cord injury

As a result of its complex histological structure, regeneration patterns of grey and white matter are quite different in the spinal cord. Therefore, tissue engineering scaffolds for repairing spinal cord injury must be able to adapt to varying neural regeneration patterns. The aim of the present study was to improve a previously reported spinal cord‐mimicking partition‐type scaffold by adding microchannels on a single tubular wall along its longitudinal axis, thus integrating the two architectures of a single H‐shaped central tube and many microchannels. Next, the integrated scaffold was loaded with bone marrow stromal cells (BMSCs) and transplanted to bridge the 5‐mm defect of a complete transverse lesion in the thoracic spinal cord of rats. Subsequently, effects on nerve regeneration, locomotion function recovery, and early neuroprotection were observed. After 1 year of repair, the integrated scaffold could guide the regeneration of axons appearing in the debris of degraded microchannels, especially serotonin receptor 1A receptor‐positive axonal tracts, which were relatively orderly arranged. Moreover, a network of nerve fibres was present, and a few BMSCs expressed neuronal markers in tubular lumens. Functionally, electrophysiological and locomotor functions of rats were partially recovered. In addition, we found that BMSCs could protect neurons and oligodendrocytes from apoptosis during the early stage of implantation. Taken together, our results demonstrate the potential of this novel integrated scaffold loaded with BMSCs to promote spinal cord regeneration through mechanical guidance and neuroprotective mechanisms.     

电针治疗大鼠慢性脊髓损伤疗效观察及分子机制的实验研究

目的 探索电针治疗慢性脊髓损伤的作用机理.方法 采用大鼠后路渐进性脊髓压迫动物模型,然后手术减压,并进行电针治疗.通过体诱发电位和BBB评分观察后肢功能,采用免疫组化和蛋白印迹法观察神经营养因子-3 （NT-3）及其受体（TrkC）的变化.结果 脊髓损伤后NT-3和TrkC在神经元及胶质细胞表达增强,经过电针治疗后, NT-3和TrkC在神经元和胶质细胞的表达下降.诱发电位检测和BBB评分显示,电针组疗效优于减压组（P〈0.05）.结论 电针治疗可促进脊髓损伤大鼠的行为功能恢复,这可能是通过内源性神经营养因子及其受体介导的.