大鼠脊髓全横断后脑源性神经营养因子及其高亲和力受体在运动皮质表达的变化

目的：研究大鼠脊髓全横断后脑源性神经营养因子（BDNF）及其高亲和力受体（TrkB）在运动皮质表达的变化，为进一步探索脊髓损伤后再生修复机制和神经营养因子治疗脊髓损伤提供实验依据。方法：雄性SD大鼠42只随机分为3组：1.脊髓横断组：动物脊髓在胸9节段完全横断，按存活时间不同分为术后3、7、14、21及28d组；2.假手术组（只行椎板切除术）；3.正常对照组。动物到达存活时间点后，应用免疫组织化学ABC方法和图像分析技术检测TrkB及BDNF在运动皮质的表达和分布。结果：对照组和实验组运动皮质TrkB和BDNF阳性细胞主要分布在第5层，第3、4、6层也有少量阳性细胞。脊髓全横断后TrkB和BDNF的表达逐渐增高，于术后21d达高峰，28d回到正常水平，且TrkB表达上调早于BDNF。结论：脊髓全横断后运动皮质对BDNF的需求增加，内源性BDNF的增加可能有利于受损的皮质脊髓束神经元的存活与再生；在损伤早期给予外源性BDNF可能更有利于受损的皮质脊髓束神经元。     

督脉电针与神经干细胞移植联合应用促进脊髓全横断大鼠受损伤的神经元存活及其轴突再生

目的探讨督脉电针与神经干细胞移植联合应用对脊髓全横断大鼠受损伤的神经元存活及其轴突再生的影响。方法将对照组、神经干细胞移植组、督脉电针组和督脉电针＋神经干细胞移植组的成年大鼠胸10脊髓段做全横断损伤;其中神经干细胞移植组和电针神经干细胞组在损伤处移植神经干细胞。电针组和电针神经干细胞移植组在术后开始接受督脉电针治疗。所有动物存活67d。结果1．电针神经干细胞移植组脊髓损伤处的去甲肾上腺素能、5-羟色胺受体、降钙素基因相关肽能和生长相关蛋白-43阳性染色的4种神经纤维均明显多于其他几组。2．电镜下可观察到脊髓横断处有再生的神经纤维穿越,在电针神经干细胞移植组尤为明显。3．大脑体感运动区皮质和中脑红核受损伤的神经元存活数量也多于其他几组,一些神经元的再生神经纤维可能穿越横断处,进入尾端脊髓组织。结论督脉电针与神经干细胞移植联合应用能促进脊髓全横断大鼠受损伤的神经元存活及其轴突再生。     

灵芝孢子和一氧化氮合酶抑制剂对大鼠脊髓损伤后背核、红核神经元存活及轴突再生的影响

目的探讨灵芝孢子和一氧化氮合酶（NOS）抑制剂（L-NNA）联合应用能否促进脊髓半横断后受损伤的背核和红核神经元存活及其轴突再生。方法30只成年雌性大鼠被分为对照组、L-NNA组、灵芝孢子低剂量组、灵芝孢子低剂量＋L-NNA组、灵芝孢子高剂量组和灵芝孢子高剂量＋L-NNA组。灵芝孢子高剂量＋L-NNA组动物在T11脊髓段半横断后注射L-NNA和胃饲高剂量灵芝孢子。结果脊髓半横断后30d,对照组L1脊髓损伤侧背核神经元数量减少,NOS表达阳性。L-NNA组和灵芝孢子低剂量组损伤侧背核神经元增加,但NOS表达降低。灵芝孢子低剂量＋L-NNA组和灵芝孢子高剂量组损伤侧背核神经元明显增加,NOS表达显著降低。灵芝孢子高剂量＋L-NNA组损伤侧背核神经元最多,NOS表达最低,而且有些神经元胞体被荧光金标记。对照组和L-NNA组损伤侧红核神经元密度降低。灵芝孢子低剂量组和灵芝孢子低剂量＋L-NNA组损伤侧红核神经元密度提高。灵芝孢子高剂量组和灵芝孢子高剂量＋L-NNA组损伤侧红核神经元密度明显提高。结论灵芝孢子和L-NNA都能促进脊髓半横断后受损伤背核神经元的存活,两者联合应用能更好地促进受损伤的背核神经元存活及其轴突再生。灵芝孢子也能促进受损伤的红核神经元存活。     

施万细胞和L-NNA对脊髓半横断后脑干红核神经元存活的影响

目的探讨移植施万细胞(SCs)和应用一氧化氮合酶抑制剂L-硝基精氨酸(L-NNA)能否促进脑干红核受损伤的神经元存活。方法20只成年SD雌性大鼠分为：对照组、SCs组、L-NNA组和SCs L-NNA组。在胸11脊髓段半横断后立即在损伤处植入SCs，术后腹腔注射L-NNA。结果脊髓半横断后30d，对照组和L-NNA组大鼠受损伤侧红核的神经元密度明显降低，但两组间无明显差异；两组受损伤侧红核神经元的NOS表达阴性。SCs组和SCs L-NNA组大鼠受损伤侧红核的神经元密度明显增加，两组间无显著差异；两组受损伤侧红核神经元NOS表达也呈阴性。结论移植的SCs能够促进受损伤的红核神经元存活。NOS可能不参与影响受损伤红核神经元的存活过程，因而L-NNA对受损伤红核神经元的存活没有作用。     

大鼠脊髓全横断损伤后Wnt信号基因的表达

目的探讨大鼠脊髓全横断损伤后,Wnt信号基因在不同时相脊髓表达的变化及意义。方法成年健康Wistar大鼠30只,随机分为假手术组(sham组)和脊髓损伤组(SCI组),SCI组分为术后1d、3d、7d、14d、21d组,每组5只。SCI组大鼠T11脊髓段做全横断损伤,sham组仅行椎板切除术,术后大鼠进行BBB运动功能评分。采用半定量RT-PCR方法检测脊髓损伤组织中Wnt信号基因的表达。结果SCI组所有动物在术后均表现为双后肢瘫痪,BBB运动功能评分明显低于sham组。SCI组在脊髓横断术后1d、3d、7d Wnt3a表达均较sham组明显增加;尾侧端Wnt3a较同时相头侧端的表达多,且在21d又出现明显的升高。在sham组和SCI组均未检测到神经基因蛋白1(Ngn1)的表达。发状分裂相关增强子1(Hes1)的表达在SCI后第1d较sham组有明显的下降,第3d出现升高,之后逐渐下降。结论Wnt信号可能参与了脊髓损伤后修复再生的过程。     

督脉电针对早期受损伤的脊髓神经营养素-3表达的影响

目的 观察督脉电针对早期受损伤的脊髓神经营养素-3(NT-3)表达的影响及其细胞定位.方法 成年雌性大鼠分为损伤组和电针加损伤组.全横断损伤两组大鼠的脊髓1d后,开始对电针+损伤组大鼠进行督脉电针,损伤组大鼠不做督脉电针.电针加损伤组在电针后1、3和7d时间点取出脊髓损伤区组织,损伤组也在相应时间点取出损伤区组织,用ELISA方法检测损伤区组织NT-3水平.再取电针后7d大鼠脊髓损伤区及其邻近组织切片做NT-3的免疫荧光组织化学双标染色.结果 电针加损伤组和损伤组的脊髓损伤区组织NT-3表达在时间上基本一致;在前3 d,NT-3水平是下降的,在后3 d,NT-3水平是增高的.但是,与损伤组相比,电针加损伤组的NT-3水平是明显增高(P＜0.05).免疫荧光双标染色结果显示,神经元、星形胶质细胞、少突胶质细胞和巨噬细胞都有NT-3的表达.结论 督脉电针可以促进受损伤早期的脊髓组织细胞合成和分泌内源性NT-3,这可能是督脉电针促进急性脊髓损伤修复的适宜微环境因素之一.     

施万细胞和一氧化氮合酶抑制剂对大鼠脊髓损伤后背核神经元存活及其轴突再生的影响

目的探讨施万细胞(SCs)和一氧化氮合酶(NOS)抑制剂L-NNA联合应用能否促进脊髓损伤后背核神经元存活及其轴突再生。方法20只成年大鼠分为对照组、SCs组、L-NNA组和SCs L-NNA组。在SCs L-NNA组动物T11脊髓段半横断后在损伤处植入施万细胞，术后腹腔内注射L-NNA。结果脊髓半横断后30d，对照组L1脊髓段损伤侧背核神经元数量减少，其胞体皱缩，NOS表达阳性。SCs组存活的神经元增加的同时其NOS表达增强，胞体也发生皱缩。L-NNA组和SCs L-NNA组存活的神经元也增加，但NOS表达降低，其胞体皱缩得到改善。各组中仅在SCs L-NNA组L1脊髓损伤侧背核观察到有被FG标记的神经元胞体，提示其再生轴突穿越损伤区到达头端脊髓组织。结论SCs和L-NNA都可促进脊髓半横断背核受损伤神经元的存活；两者联合应用能更好地促进受损伤背核神经元存活及其轴突再生。     

脊髓损伤亚急性期移植神经干细胞：损伤脊髓5-羟色胺的表达☆

背景：5-羟色胺能纤维可以作为评价脊髓损伤后再生的指标之一。 目的：观察神经干细胞在脊髓损伤的亚急性期(第7天)脊髓内移植对大鼠受损伤脊髓再生修复的影响。 方法：将正常成年SD雌性大鼠分为3组,单纯脊髓全横断组、假手术组(仅仅打开椎板,但不横断脊髓)、神经干细胞移植组。神经干细胞移植组在脊髓全横断后第7天时进行神经干细胞移植,其他两组不移植神经干细胞。 结果与结论：神经干细胞移植组瘢痕上1至2节段5-羟色胺的阳性纤维数量多于单纯脊髓全横断组。提示神经干细胞亚急性期移植能部分促进脊髓损伤后脊髓神经的再生。 关键词：脊髓损伤;再生;神经干细胞;5-羟色胺;大鼠 doi:10.3969/j.issn.1673-8225.2012.06.023     

三七总皂甙对大鼠脊髓损伤后背核和红核神经元存活的影响

目的探讨三七总皂甙对脊髓半横断后受损伤背核和红核神经元存活以及背核神经元表达一氧化氮合酶(NOS)的影响。方法25只成年雌性大鼠在施行脊髓半横断术后,被分为对照组、三七总皂甙低剂量组、三七总皂甙中剂量组、三七总皂甙高剂量组和L-NNA组。三七总皂甙组每天胃饲一定剂量的三七总皂甙,L-NNA组每d腹腔内注射L-NNA。术后30d取出脊髓和大脑行冷冻切片,做NADPH酶组化染色和中性红染色。结果脊髓半横断后,对照组损伤侧背核神经元和红核神经元数目明显降低,背核面积减少,背核NOS阳性神经元增多;应用三七总皂甙和L-NNA后,损伤侧背核神经元数目和背核面积有恢复性增加,尤其是高剂量三七总皂甙的效果更明显。三七总皂甙和L-NNA均可抑制受损伤的背核神经元表达NOS,三七总皂甙还可提高损伤侧红核神经元的存活率。结论三七总皂甙能够促进受损伤的背核神经元和红核神经元的存活,同时能够抑制受损伤的背核神经元表达NOS。     

脊髓半横断损伤后腹角神经元神经生长因子、脑源性神经营养因子、神经营养因子-3和神经营养因子-4表达的变化

目的:探讨大鼠脊髓半横断损伤(htSCI)后脑源性神经营养因子(BDNF)、神经生长因子(NGF)、神经营养因子(NT-3、NT-4)在脊髓腹角神经元表达的早期变化。方法:免疫组织化学ABC法分别染4种神经因子并作阳性细胞计数。结果:NGF主要分布于脊髓腹角神经元的胞核,BDNF、NT-4与NT-3主要分布于胞浆。htSCI前后它们在细胞内的分布范围没有变化。BDNF、NGF与NT-3的3 d在损伤尾侧段脊髓双侧腹角阳性神经元数与对照组相比显著减少。BDNF与NGF的14 d的双侧腹角阳性神经元数量均较正常组明显增多,NT-3与NT-4的14 d~21 d的双侧腹角阳性神经元数量均较正常组明显增多,BDNF7~21 d以及NGF14 d的健侧的阳性神经元数量均分别多于相应的伤侧。结论:内源性BDNF、NGF、NT-3、NT-4增加对脊髓损伤修复具有重要作用,BDNF和NGF在健侧表达的增加说明健侧代偿功能的活跃。     

脊髓横断损伤后再生基因蛋白的表达

目的探讨再生基因蛋白(Reg-2)在脊髓横断损伤后表达的时序变化及其可能的意义。方法SD雌性大鼠45只,实验分为脊髓损伤组(30只)、假手术组(15只)。脊髓损伤组大鼠麻醉后于T9、T10脊髓节段之间用手术刀完全切断脊髓,建立大鼠脊髓横断损伤模型;假手术组大鼠只打开推板,不损伤脊髓,为阴性对照。分别于脊髓损伤后1h、1d、3d、7d1、4d用多聚甲醛灌注后,以T10节段为中心取出长约2cm的脊髓,制作冠状切面及横断切面冷冻切片。分别通过免疫组织化学、免疫荧光和Western blotting法检测Reg-2的表达水平及部位,并与胶质纤维酸性蛋白(GFAP)、少突胶质细胞系转录因子2(Olig2)以及神经肽Y(NPY)、降钙素基因相关肽(CGRP)、神经性生长蛋白-43(GAP-43)等神经细胞特异性标记物做双重标记。结果脊髓损伤组中,表达Reg-2的阳性细胞随着时间的推移,先增加后减少,脊髓损伤后的1周内维持在较高水平,其中第3d后角神经元的Reg-2表达最高,第7d前角神经元Reg-2的表达最高。结论Reg-2可能参与了脊髓损伤后早期的神经再生和重建进程。     

Matrix inclusion within synthetic hydrogel guidance channels improves specific supraspinal and local axonal regeneration after complete spinal cord transection

We have previously shown that a novel synthetic hydrogel channel composed of poly(2-hydroxyethyl methacrylate-co-methyl methacrylate) (pHEMA-MMA) is biocompatible and supports axonal regeneration after spinal cord injury. Our goal was to improve the number and type of regenerated axons within the spinal cord through the addition of different matrices and growth factors incorporated within the lumen of the channel. After complete spinal cord transection at T8, pHEMA-MMA channels, having an elastic modulus of 263+/-13 kPa were implanted into adult Sprague Dawley rats. The channels were then filled with one of the following matrices: collagen, fibrin, Matrigel, methylcellulose, or smaller pHEMA-MMA tubes placed within a larger pHEMA-MMA channel (called tubes within channels, TWC). We also supplemented selected matrices (collagen and fibrin) with neurotrophic factors, fibroblast growth factor-1 (FGF-1) and neurotrophin-3 (NT-3). After channel implantation, fibrin glue was applied to the cord-channel interface, and a duraplasty was performed with an expanded polytetrafluoroethylene (ePTFE) membrane. Controls included animals that had either complete spinal cord transection and implantation of unfilled pHEMA-MMA channels or complete spinal cord transection. Regeneration was assessed by retrograde axonal tracing with Fluoro-Gold, and immunohistochemistry with NF-200 (for total axon counts) and calcitonin gene related peptide (CGRP, for sensory axon counts) after 8 weeks survival. Fibrin, Matrigel, methylcellulose, collagen with FGF-1, collagen with NT-3, fibrin with FGF-1, and fibrin with NT-3 increased the total axon density within the channel (ANOVA, p<0.05) compared to unfilled channel controls. Only fibrin with FGF-1 decreased the sensory axon density compared to unfilled channel controls (ANOVA, p<0.05). Fibrin promoted the greatest axonal regeneration from reticular neurons, and methylcellulose promoted the greatest regeneration from vestibular and red nucleus neurons. With Matrigel, there was no axonal regeneration from brainstem motor neurons. The addition of FGF-1 increased the axonal regeneration of vestibular neurons, and the addition of NT-3 decreased the total number of axons regenerating from brainstem neurons. The fibrin and TWC showed a consistent improvement in locomotor function at both 7 and 8 weeks. Thus, the present study shows that the presence and type of matrix contained within synthetic hydrogel guidance channels affects the quantity and origin of axons that regenerate after complete spinal cord transection, and can improve functional recovery. Determining the optimum matrices and growth factors for insertion into these guidance channels will improve regeneration of the injured spinal cord.     

大鼠脊髓全横断后脊髓内NGF、NT3表达的变化

目的探讨大鼠脊髓全横断后不同时相（3、7、14、21天）脊髓内NGF，NT3表达的变化。方法采用免疫组织化学ABC法及阳性神经元计数，来检测脊髓全横断后不同时相NGF、NT-3的表达。结果（1）脊髓全横断后脊髓腹、背角NGF阳性细胞数均较正常增多（P〈0．05），尤以7天明显；脊髓全横断后脊髓腹、背角NT-3阳性细胞数均较正常增多（P〈0．01），尤以7天明显。结论NGF、NT-3表达的变化可能与脊髓可塑性有关。（2）NGF、NT-3阳性细胞数在各时相均比正常增多，说明NGF、NT-3在脊髓全横断后呈持续性表达增加。     

Role of Neurotrophin 3 in spinal neuroplasticity in rats subjected to cord transection

That neuroplasticity occurs in mammalian spinal cord is well known, though the underlying mechanism still awaits elucidation. This study evaluated the role of endogenous Neurotrophin-3 (NT-3) in the spinal neuroplasticity. Following cord transection at the junction between T9 and T10, the hindlimb locomotor functions of rats showed gradual but significant improvement from 7 to 28 days post-operation. Corresponding to this was a significant increase in the level of NT-3 in the cord segments caudal to injury site. Significantly, after NT-3-antibody administration, the spinal transected rats displayed poor hindlimb locomotor functions and a decrease in the number of neurons in spinal laminae VIII–IX. Whether NT-3-antibody was administered, corticospinal tract regeneration and somatosensory evoked potentials could not be detected. Our findings suggested that endogenous NT-3 could play an important role in spinal plasticity in adult spinal cords subjected to transection, possibly through a regulation of neuronal activity in the local circuitry.     

神经营养因子-3对大鼠脊髓半横断后背根神经节c-Jun表达的影响

目的：研究神经营养因子-3(NT-3)对脊髓半横断后背根神经节c-Jun表达的影响，探索NT-3促进脊髓修复的作用机制。方法：将实验动物分为：对照组，损伤组和NT-3注射组，应用荧光免疫组化法结合激光扫描共聚焦显微镜，观察各组背根神经节c-Jun的表达，并计数细胞核完整的神经元数目。结果：脊髓损伤后，背根神经节的细胞内c-Jun的表达上调；NT-3注射组脊髓损伤侧背根神经节神经元的c-Jun表达明显上调，背根神经节内细胞核呈完整状态的神经元数量明显增多。结论：(1)c-Jun在轴突损伤后表达上调。(2)NT-3对轴突损伤后的神经元有保护作用。(3)NT-3可能通过使c-Jun表达上调而发挥其促神经再生作用。     

大鼠脊髓缺血再灌注损伤后caspase-12表达与细胞凋亡

目的:观察大鼠脊髓缺血再灌注损伤过程中细胞凋亡、caspase-12的表达变化规律,以探讨其分子机制。方法:采用自制压迫装置制备脊髓压迫缺血再灌注模型。运用形态学、分子生物学等方法,分别于缺血再灌注后3、7、11、23和47h,观察脊髓缺血再灌注损伤后,脊髓的病理变化和内质网的形态学改变、细胞凋亡及caspase-12的表达变化的规律。结果:脊髓缺血再灌注3h后,出现不同程度的细胞肿胀,神经元退行性变及内质网结构变化;随着再灌注时间的延长,神经元和神经胶质细胞凋亡数明显增加,并伴有caspase-12的表达增强;capspase-12表达与细胞凋亡的时空变化规律相一致。结论:在脊髓缺血再灌注过程中神经细胞凋亡是引起脊髓继发性损伤的主要病理因素,caspase-12可能参与了脊髓缺血再灌注损伤所导致的细胞凋亡。     

Cograft of neural stem cells and schwann cells overexpressing TrkC and neurotrophin-3 respectively after rat spinal cord transection

Effectively bridging the lesion gap is still an unmet demand for spinal cord repair. In the present study, we tested our hypothesis if cograft of Schwann cells (SCs) and neural stem cells (NSCs) with genetically enhanced expression of neurotrophin-3 (NT-3) and its high affinity receptor TrkC, respectively, could strengthen neural repair through increased NSC survival and neuronal differentiation at the epicenter after complete T10 spinal cord transection in adult rats. Transplantation of NT-3-SCs?+?TrkC-NSCs in Gelfoam (1?×?10(6)/implant/rat; n?=?10) into the lesion gap immediately following injury results in significantly improved relay of the cortical motor evoked potential (CMEP) and cortical somatosensory evoked potential (CSEP) as well as ameliorated hindlimb deficits, relative to controls (treated with LacZ-SCs?+?LacZ-NSCs, NT-3-SCs?+?NSCs, NSCs alone, or lesion only; n?=?10/group). Further analyses demonstrate that NT-3-SCs?+?TrkC-NSCs cografting augments levels of neuronal differentiation of NSCs, synaptogenesis (including inhibitory/type II-like synapses) and myelin formation of SCs, in addition to neuroprotection and outgrowth of serotonergic fibers in the lesioned spinal cord. Compared with controls, the treated spinal cords also show elevated expression of laminin, a pro-neurogenic factor, and decreased presence of chondroitin sulfate proteoglycans, major inhibitors of axonal growth and neuroplasticity. Together, our data suggests that coimplantation of neurologically compatible cells with compensatorily overexpressed therapeutic genes may constitute a valuable approach to study, and/or develop therapies for spinal cord injury (SCI).