慢性颈脊髓压迫模型大鼠构建及评价

背景：在脊髓型颈椎病脊髓损伤发生机制的研究过程中,建立稳定且同人类体内疾病演变过程相似的疾病模型对于研究脊髓型颈椎病发病机制至关重要。 目的：构建慢性颈脊髓压迫模型,观察该模型病理生理变化特点,进一步明确脊髓型颈椎病受压脊髓组织的病理改变。 方法：30只SD大鼠随机均分为对照组、轻度压迫组、重度压迫组。将不同大小吸水性压迫材料聚乙烯醇丙烯酰胺互穿网络水凝胶植入C5-C7椎板下,制作慢性颈脊髓压迫动物模型,对照组不植入压迫材料。 结果与结论：MRI检查显示两压迫组大鼠出现不同程度的椎管狭窄和脊髓压迫,而对照组椎管宽度正常无脊髓压迫。电生理检测显示两压迫组大鼠运动诱发电位潜伏期较对照组明显延长且振幅明显降低(P < 0.05)。神经元免疫荧光染色显示对照组大鼠脊髓有大量形态规则的神经元,而两压迫组大鼠神经元计数明显减少且神经元胞体形态明显皱缩,脱髓鞘现象明显,3组间比较差异有显著性意义(P < 0.05)。压迫组大鼠脊髓压迫节段发现较多凋亡细胞,而对照组未发现。说明构建的大鼠慢性颈脊髓压迫模型符合脊髓型颈椎病的病理改变,且手术操作简便,不易感染死亡率低;神经元损伤、脱髓鞘改变和凋亡机制参与了大鼠慢性颈脊髓压迫损伤的发生发展过程。     

电针调节糖原合成酶激酶3β/β-catenin信号通路对脊髓损伤大鼠室管膜区细胞CD133蛋白表达的影响

背景：前期研究表明,电针可改善脊髓损伤后功能障碍,并促进脊髓损伤后大鼠内源性神经干细胞增殖,然而其具体作用机制不明确。目的：观察电针对脊髓损伤大鼠糖原合成酶激酶3β/β-catenin信号通路相关因子表达和室管膜区细胞CD133蛋白表达的影响,探讨电针促进内源性干细胞增殖的作用机制。方法：将45只SD雌性大鼠随机分为假手术组、模型组、电针组,每组15只,后两组以精密打击器构建脊髓损伤大鼠模型。在造模后24 h,电针组接受电针治疗,选取督脉“百会”“脊中”穴及损伤脊髓上下节段夹脊穴,予疏密波,频率1 Hz/20 Hz,强度1.0-1.2 mA,30 min/次,1次/d,持续14 d。应用BBB运动功能评分评估大鼠运动功能,Nissl染色观察脊髓组织病理形态学改变及神经元数量,免疫荧光检测脊髓组织中室管膜区细胞CD133、脊髓灰质和白质中Nestin荧光强度,实时荧光定量PCR检测脊髓组织中Nestin、糖原合成酶激酶3β、β-catenin mRNA表达,Western blot检测脊髓组织中Nestin、糖原合成酶激酶3β、磷酸化糖原合成酶激酶3β、β-catenin、p-β-cat...     

BMP7蛋白对大鼠急性脊髓损伤后神经元修复作用的研究

目的探索骨形态发生蛋白7(bone morphogenetic protein 7,BMP7)是否具有促进大鼠急性脊髓损伤后神经元修复的作用。方法实验大鼠分为阴性对照组(negative control,NC)和BMP7实验组,以Allen's打击法建立大鼠脊髓损伤模型,BMP7组大鼠每天在脊髓损伤处注射50ng BMP7蛋白,连续7天,NC组对应注射等体积的0.9%氯化钠注射液。两组大鼠分别于术后6小时、3天、1周、2周、4周、8周进行HE染色以观察脊髓损伤处病理学改变;两组大鼠分别于术后6小时、3天、1周、2周、4周、8周进行免疫组化实验以检测损伤节段脊髓神经丝蛋白200(neurofilament protein 200,NF200)、胶质纤微酸性蛋白(glial fibrillary acidic protein,GFAP)及突触素(Synaptophysin,SYP)蛋白表达水平。结果 HE染色结果表明两组大鼠造模后脊髓损伤处神经元数量减少,神经突触数量减少,尼式体淡染且数量减少,组织中可见空洞形成,1周后,BMP7实验组大鼠脊髓损伤处尼式体染色逐渐加深,神经突触数量增多,变化较NC组明显。免疫组化结果表明BMP7实验组大鼠NF200阳性表达细胞数造模3天后逐渐增多,至第4周时达到高峰,且在1周、2周、4周及8周时均大于NC组;BMP7实验组及NC组术后GFAP阳性表达细胞数变化均不明显,且两组阳性细胞数差异不显著;BMP7实验组大鼠SYP阳性表达细胞数造模3天后逐渐增多,且在1周、2周、4周及8周时均大于NC组。结论 BMP7蛋白可以促进大鼠脊髓损伤后神经元的修复。     

大鼠脊髓慢性压迫损伤模型的建立

目的 建立一种大鼠脊髓慢性压迫性损伤模型.方法 将慢性膨胀物于显微镜下植入大鼠T8/9水平,随着压迫物的膨胀,逐渐形成不同程度的慢性压迫脊髓损伤实验动物模型.手术后通过BBB评分进行行为学功能评定,检测压迫段脊髓病理标本及通过电脑图像分析系统半定量检测凋亡启动基因P53.结果 术后观察行为学、组织学、病理学上的改变,3者相符合.结论 此模型较以往模型相比,具有制作简单,损伤程度可调整,脊髓损伤能表现出不同的压迫程度,可重复性强等优点.为进一步研究脊髓慢性压迫损伤病理机制奠定基础.     

脊髓慢性受压后神经性一氧化氮合酶表达的变化

目的　探讨慢性脊髓压迫性损伤时 ,脊髓组织神经性一氧化氮合酶 (nNOS)免疫组织化学的变化及其与脊髓病理变化之间的关系。　方法　健康家兔 18只 ,随机分为正常对照组、实验对照组及实验组。实验组采用泛影葡胺囊逐级压迫复制慢性脊髓压迫动物模型 ,并持续逐级压迫脊髓 12周。取 3组家免相应脊髓节段 ,用Nissl染色观察脊髓的病理变化 ;用免疫组织化学方法对脊髓组织nNOS阳性运动神经元分布特点和nNOS含量变化进行分析。　结果　Nissl染色可见实验组脊髓压迫节段前角运动神经元损伤 ;实验组家免脊髓压迫节段前角nNOS阳性运动神经元较正常及实验对照组各个脊髓节段异常增加。　结论　在慢性脊髓压迫时 ,神经性NO合成增加     

督脉电针对脊髓损伤大鼠神经干细胞的作用

目的　观察督脉电针对脊髓损伤后大鼠脊髓巢蛋白 (Nestin)表达和后肢功能的影响。方法　于术后 1、7、14、2 1和 2 8d分别对大鼠进行Tarlov评分和斜板试验检查后肢功能后处死动物 ,应用免疫组织化学技术检测神经上皮干细胞蛋白(Nestin)的表达 ,采用计算机图像分析仪进行定量分析 ,观察督脉电针对脊髓损伤后神经上皮干细胞蛋白的影响。结果　脊髓损伤后第 1d ,在督脉电针组和单纯脊髓损伤组的损伤脊髓灰质中都可见到Nestin的表达。单纯脊髓损伤组在术后第 7、14、2 1和 2 8d ,Nestin阳性细胞数分别为 2 1 4 8± 7 83、11 78± 4 38和 9 18± 3 2 6 ,而督脉电针组分别为 30 6 9± 6 16、39 2 4± 6 83、2 6 4 9± 5 87和 2 2 30± 6 6 1,两组在 4个时间段上均有显著性差异 (P <0 0 5 )。增加的Nestin阳性细胞数与神经功能的改善平行。结论　提示督脉电针可减轻神经损伤症状和促进脊髓损伤后神经干细胞的增殖。     

EphB3基因受体蛋白在大鼠脊髓损伤组织中的表达

背景：Eph受体能够调节轴突介导,形成抑制轴突修复再生的内环境,而EphB3又是Eph家族中极其重要的一员,所以研究EphB3与脊髓损伤的关系将成为国内外研究的新方向。 目的：观察脊髓损伤大鼠EphB3基因和蛋白的表达情况。 方法：采用脊髓半切法建立大鼠脊髓损伤模型,RT-PCR和Western blot法检测脊髓损伤后1,2,4,8周脊髓组织中EphB3 mRNA及蛋白的表达,并且与正常大鼠进行比较。 结果与结论：损伤组脊髓组织中EphB3 mRNA及蛋白呈高表达,且1,2,4,8周时间点EphB3 mRNA及蛋白表达无明显变化(P ≥ 0.05)。对照组脊髓组织中EphB3 mRNA及蛋白表达极低。两组比较差异有显著性意义(P < 0.05)。结果提示脊髓损伤引起EphB3基因和蛋白呈长时间稳定的高表达。     

脊髓损伤后神经型一氧化氮合酶基因表达的变化

目的 :研究大鼠脊髓损伤后神经型一氧化氮合酶 (nNOS)mRNA表达的变化规律。方法 :参考Nystrom方法建立大鼠脊髓压迫伤模型 ,用逆转录聚合酶链反应 (RT PCR)法测定伤段脊髓组织nNOSmRNA的表达情况。结果 :正常脊髓组织内存在nNOSmRNA的表达 ,脊髓压迫伤后nNOSmRNA表达迅速逐渐增强 ,在伤后 6h达到高峰。结论 :nNOS存在于正常的脊髓组织内 ,脊髓损伤后nNOSmRNA表达迅速增强 ,提示nNOS参与了继发性脊髓损伤过程 ,并可能是一种损伤因素。     

大鼠脊髓压迫损伤后COX-2基因和蛋白的表达

目的观察大鼠脊髓压迫损伤后COX-2mRNA和蛋白在脊髓组织内表达的时间特征,以及COX-2的空间分布特点。方法以压迫装置致脊髓损伤后,在伤后不同时间点(30min、3h、6h、24h、72h、1w)分别应用RT-PCR、Western blotting、免疫组化技术检测COX-2mRNA和蛋白表达和分布。结果RT-PCR和Western blotting显示,COX-2mRNA和蛋白伤后30min表达开始增加,于伤后6h达到峰值,伤后1w表达接近基础水平。免疫组化提示,COX-2蛋白在假手术组表达仅见于脊髓血管内皮细胞,伤后COX-2蛋白表达见于损伤区附近脊髓灰质内的神经元和血管内皮细胞,损伤中心部位COX-2免疫阳性细胞少见。结论脊髓压迫损伤早期可快速诱导COX-2基因的表达上调和蛋白的合成,伤后COX-2蛋白分布发生变化,主要位于脊髓神经元和血管内皮细胞。     

大鼠脊髓慢性压迫性损伤实验模型的建立

目的：建立一种新型大鼠脊髓慢性压迫实验动物模型，为探索脊髓受压后的病理生理机制奠定基础。方法：根据大鼠脊柱解剖结构特点自行设计一种大鼠脊髓压迫器，用以制作大鼠慢性压迫模型。运用行为学、影像学、TTC、HE、Tunnel等方法，了解动物行为学变化及受压节段脊髓病理学改变，以评价模型的可靠性。结果：脊髓压迫后渐次出现肌力减退、行动瘫痪；TTC结果显示，在各时段可见脊髓缺血范围与压迫时间及压迫强度相关；压迫后，脊髓出现组织水肿、神经元空泡化、白质疏网状改变及退行性变，以及神经元和胶质细胞的凋亡。结论：（1）用大鼠脊髓压迫器制作的大鼠脊髓慢性压迫缺血性损伤模型，具有方法简单、科学、重复性强等特点；（2）脊髓压迫程度可根据实验目的不同进行调节；（3）本实验为脊髓压迫性损伤机制的研究提供了一种理想的动物试验模型。     

Embryonic intermediate filament,nestin, expression following traumatic spinal cord injury in adult rats

Precursor cells in the ependyma of the lateral ventricles of adult mammalian brain have been reported in brain, and also in the spinal cord. The present study used antibody to the intermediate filament protein (nestin) as an immunohistochemical marker for neural stem cells and precursor cells in a rat model of spinal cord trauma. Male Sprague-Dawley rats (n=25) had a laminectomy at Thll-Thl2, and spinal cord contusion was created by compression with 30 g of force for 10 min. The rats were killed at 24 h, 1 week and 4 weeks after injury, and four levels of the spinal cord were examined: 5 mm and 10 mm, both rostral and caudal region to the injury center. Time- and region-dependent alterations of nestin immunoreactivity were analyzed. Revealed at 24 h post-injury, 5 mm rostral and caudal to the lesions, nestin expression was observed in ependymal cells and around the hemorrhagic and necrotic lesion located in dorsal spinal cord, peaking at 1 week after injury. Moreover, nestin expression was also observed in the white matter of ventral spinal cord, extending into arborizing processes centripetally from the pial surface toward the central canal. At 4 weeks after injury, nestin expression in ependyma decreased 10 mm from the injury site. But nestin expression in white matter increased dramatically with a 100-fold increase in nestin originating from the pial surface, and extension now to all the white matter. The latter was accompanied by glial fibrillary acidic protein positivity into very long arborizing processes, morphologically compatible with radial glia. The findings suggest two possible sources of precursor cells in adult mammalian spinal cord; ependyma of the central canal and subpial astrocytes. Subpial astrocytes may be associated with neural repair and regeneration after spinal cord injury.     

脊髓全横断模型大鼠损伤区白细胞介素17的表达

背景：现阶段,针对已知的炎性递质的干预措施对于减轻脊髓继发损伤的效果局限。白细胞介素17是重要的促炎性细胞因子,在中枢神经系统疾病发病机制中的作用正逐渐受到关注。 目的：观察急性脊髓损伤模型大鼠白细胞介素17 mRNA和蛋白表达的变化规律。 方法：健康雄性SD大鼠随机分为2组：模型组制作大鼠脊髓完全横断模型,假手术组仅剪开硬脊膜而不伤及脊髓实质。开放后测定肢运动功能评分观察急性脊髓损伤对大鼠运动功能的影响,苏木精-伊红染色观察脊髓损伤后不同时间点组织病理学改变,实时荧光定量PCR、Western blot分别检测各组大鼠脊髓损伤后不同时间点白细胞介素17 mRNA和蛋白水平表达变化。 结果与结论：开放后肢运动功能评分结果：假手术组大鼠BBB评分均为20-21分,脊髓损伤1,2 d大鼠BBB评分均为0分,损伤后7 d BBB评分为0-3分(P < 0.05)。苏木精-伊红染色结果：与假手术组相比,脊髓损伤6 h后,炎性细胞浸润,神经元和胶质细胞肿胀,神经元突起减少;脊髓损伤12 h后,灰质、白质组织结构疏松、空泡化;脊髓损伤后7 d,胶质细胞增生,组织纤维化明显。RT-qPCR结果显示：白细胞介素17 mNA于脊髓损伤后3 h出现,并于6 h表达出现高峰(P < 0.01),随后表达减少,7 d后表达接近假手术组水平。Western blot结果显示：脊髓损伤6 h后,白细胞介素17表达开始升高,并于损伤后12 h出现高峰(P < 0.05),随后表达减少,至伤后7 d表达接近假手术组水平。结果可见脊髓损伤12 h后组织损伤表现最严重,并与白细胞介素17表达改变存在时间的一致性,推断白细胞介素17可能参与了脊髓继发性炎症反应过程。 中国组织工程研究杂志出版内容重点：肾移植;肝移植;移植;心脏移植;组织移植;皮肤移植;皮瓣移植;血管移植;器官移植;组织工程全文链接：     

脊髓全横断大鼠模型的构建

背景：脊髓全横断模型在造模时常难以保证神经纤维的完全离断。 目的：构建大鼠脊髓全横断损伤模型。 方法：将大鼠随机分为模型组和假手术组。模型组构建脊髓T10节段全横断模型;假手术组动物仅打开椎管与硬脊膜而后缝合,但不损伤脊髓。建模后1,3,5,7 d分别进行BBB评分以评估后肢运动功能,检测其体感诱发电位和运动诱发电位来评估神经传导通路的完整性,并行形态学观察来评估脊髓肉眼观病理形态。 结果与结论：与假手术组相比,模型组大鼠在建模后1,3,5,7 d时,其BBB评分降低(P < 0.01),未检测出体感和运动诱发电位。形态学观察结果显示模型组大鼠脊髓完全横断,而假手术组脊髓形态完整。结果提示实验成功构建了大鼠脊髓全横断模型。     

骨形成蛋白4对脊髓损伤后大鼠功能和神经干细胞的影响

目的　观察骨形成蛋白 4对脊髓损伤后大鼠功能和神经干细胞的影响。方法　应用改良Allen脊髓损伤模型 ,将成年SD大鼠 6 0只随机分为BMP 4组、脊髓损伤组。分别于术后 1d、7d、14d、2 1d、2 8d处死动物 ,并且对大鼠进行Tarlov评分和斜板试验检查后肢功能。应用免疫组织化学技术检测巢蛋白 (nestin)的表达 ,观察BMP4对脊髓损伤后nestin表达的影响。结果　第 2 1d时BMP4组大鼠功能改善明显与损伤组比较差异有显著性意义 (P <0 0 5 ) ;脊髓损伤后第 1天 ,在BMP4组和脊髓损伤组的室管膜、室管膜下区、损伤脊髓灰质中都可见到nestin的表达。于损伤后迅速增加 ,第 14天时达到高峰。BMP4组灰质nestin表达为 15 35± 3 83,脊髓损伤组灰质为 8 4 8± 3 5 3,两者差异有显著性 (P <0 0 1)。BMP4组可使损伤的脊髓中nestin持续高表达至术后第 2 8天 ,而脊髓损伤组仅持续表达至术后 2 1d。增加的nestin阳性细胞数与神经功能的改善平行。结论　提示BMP4可减轻神经损伤症状和对脊髓损伤后神经干细胞有促进增殖作用。     

电刺激促进大鼠脊髓钝挫伤后运动功能恢复

目的探究神经电刺激对大鼠脊髓顿挫伤(SCC)后的干预效果并探讨相应机制。方法将大鼠分为:假手术组、对照组和实验组。用Allen’s法复制大鼠T9脊髓钝挫伤模型。实验组用神经电刺激干预。定期观察大鼠后肢运动功能恢复情况;用免疫组织化学染色技术以及蛋白质印记技术检测神经生长因子和巢蛋白的表达。结果脊髓损伤后,大鼠的运动功能迅速下降。随着时间的推移,实验组大鼠运动功能评分逐渐升高,第7天较对照组明显上调(P<0.05)。与对照组相比,实验组神经生长因子和巢蛋白表达明显上调(P<0.05)。结论电刺激可能创造有利于神经元存活和可塑性的微环境,有利于大鼠后肢运动功能的恢复。     

丙泊酚干预脊髓损伤模型脊髓水肿及后肢电生理的变化

BACKGROUND: A large number of studies have verified that propofol could effectively reduce secondary nerve injury by improving microenvironment of spinal cord injury. OBJECTIVE: To study the effects of propofol on spinal cord edema and electrophysiology of the hind limb in rats with spinal cord injury. METHODS: Rat models of acute spinal cord injury were established by using the modified Allen method. A total of 40 rat models were randomly divided into spinal cord injury group and propofol group (n=20). Rats in the propofol group were injected with propofol through the caudal vein. The spinal cords of an additional 20 rats were exposed in the sham surgery group. Motor function was evaluated using BBB score and inclined plate test before modeling, 1, 3 days, 1-4 weeks after modeling. Neuronal apoptosis was detected after spinal cord injury using TUNEL assay at 72 hours after modeling. AQP4/9, matrix metalloproteinases 9/2 mRNA and protein expressions were measured using RT-PCR and western blot assay. At 4 weeks after modeling, pathological changes of the spinal cord were observed using immunohistochemistry and hematoxylin-eosin staining. Neurophysiological recovery was analyzed using motor evoked potentials and somatosensory evoked potentials. RESULTS AND CONCLUSION: (1) At 1-4 weeks after modeling, BBB score and inclined plate test score were higher in the propofol group than in the spinal cord injury group (P < 0.05), but lower than in the sham surgery group (P < 0.05). (2) The number of apoptotic cells was significantly more in the spinal cord injury group than in the propofol group (P < 0.05). No apoptotic cells were found in the sham surgery group. (3) At 72 hours after spinal cord injury, AQP4/9 and matrix metalloproteinases 9/2 mRNA and protein expression was higher in the propofol group than in the sham surgery group (P < 0.05). AQP4/9 and matrix metalloproteinases 9/2 mRNA and protein expression was significantly reduced in the propofol group (P < 0.05). (4) At 4 weeks after modeling, the spinal cord was loose, and the cavity was small. Partial neuronal necrosis could be seen. The degree of nerve fiber density in the propofol group was between the sham surgery group and spinal cord injury group. (5) Motor evoked potentials and somatosensory evoked potentials were obviously recovered, the latency was short, amplitude was increased in the propofol group, which showed significant differences as compared with the sham surgery group and the spinal cord injury group (P < 0.05). Results suggested that propofol can reduce apoptosis in rat neurons after spinal cord injury, reduce spinal cord edema-related gene expression, and improve electrophysiological function and limb motor function.       

Astrocytes in injured adult rat spinal cord may acquire the potential of neural stem cells

It has been well documented that in adult rats astrocytes in the subventricular zone and subgranular layer of the dentate gyrus are neural stem cells. Elsewhere in the CNS astrocytes are not generally recognized as stem cells. Here we describe nestin expression in a population of astrocytes in the spinal cord of adult rat following cord injury. In either hemitransectioned or longitudinally cut spinal cord, there was widespread nestin expression in astrocytes of both the gray and white matters. Isolation of the lateral part of the spinal cord from the central canal region, where stem cells may reside, could not block the appearance of nestin-immunoreactive astrocytes in the lateral cord, and none of them showed Fast DiI labeling after the central canal ependyma had been labeled by the dye, indicating that the nestin-immunoreactive astrocytes can evolve locally in the lateral cord. They were found to be undergoing a process of de-differentiation. Culture of the nestin-immunoreactive astrocytes of the lateral cord generated neurospheres, the cells of which had the ability of self-renewal, and were able to differentiate into neurons, astrocytes, or oligodendrocytes. Taken together, the results indicate that the astrocytes in injured adult rat spinal cord may acquire the potential of neural stem cells.     

Endogenous neural stem cells in central canal of adult rats acquired limited ability to differentiate into neurons following mild spinal cord injury

Endogenous neural stem cells in central canal of adult mammalian spinal cord exhibit stem cell properties following injury. In the present study, the endogenous neural stem cells were labeled with Dil to track the differentiation of cells after mild spinal cord injury (SCI). Compared with 1 and 14 days post mild injury, the number of endogenous neural stem cells significantly increased at the injured site of spinal cord on 3 and 7 days post-injury. Dil-labeled βIII-tublin and GFAP expressing cells could be detected on 7 days post-injury, which indicated that the endogenous neural stem cells in central canal of spinal cord differentiated into different type of neural cells, but there were more differentiated astrocytes than the neurons after injury. Furthermore, after injury the expression of inhibitory Notch1 and Hes1 mRNA began to increase at 6 hours and was evident at 12 and 24 hours, which maintained high levels up to 7 days post-injury. These results indicated that a mild SCI in rat is sufficient to induce endogenous neural stem cells proliferation and differentiation. However, the ability to differentiate into neurons is limited, which may be, at least in part, due to high expression of inhibitory Notch1 and Hes1 genes after injury.