兔颈脊髓半侧挫伤模型的建立及其MRI和组织学表现的研究

目的 建立兔颈脊髓半侧挫伤模型,观察不同程度损伤24小时后其MRI及组织学表现。方法 22只成年雄性新西兰兔,随机分为中度损伤组（n=9）、重度损伤组（n=9）和假手术组（n=4）。直径为3.0 mm的打击头由电磁伺服材料试验机驱动,对准C5脊髓左侧行高速挫伤（500 mm/s）。根据打击头的位移距离分为位移2.0 mm组（中度损伤组）和位移2.8 mm组(重度损伤组)。假手术组仅暴露C5脊髓,不进行挫伤。损伤后24小时每组随机取两例行MRI影像学检查,所有动物均取材进行组织学观察,测量横断面脊髓出血面积。 结果 中度损伤组打击力和位移分别为(2.47±0.39) N和(1.99±0.02) mm,重度损伤组打击力和位移分别为(5.16±0.82) N和(2.76±0.02) mm,中度损伤组的打击力明显小于重度损伤组（P<0.05）。MRI结果显示,中度及重度损伤组均可见C5左侧脊髓信号改变。HE染色显示脊髓左侧有明显的出血及脊髓组织结构破坏,中度损伤组损伤中心横截面出血面积（0.012±0.006）mm2明显小于重度损伤组（0.039±0.006）mm2（P<0.05）。 结论 本文建立的兔颈脊髓半侧挫伤模型能够控制挫伤位移,实现对脊髓的高速打击。不同程度的颈脊髓半侧挫伤在打击力、MRI影像学及组织学上均有不同。     

大鼠新型挫伤型脊髓损伤模型的建立及评价

目的:制备新型挫伤型脊髓损伤大鼠模型,通过行为学评分和形态学方法进行评价,为进一步研究脊髓损伤的机制及早期治疗提供依据。方法:SD大鼠随机分为对照组和实验组,对照组(A组)采用改良的Allen法制备急性脊髓挫伤模型,实验组在打击的基础上分别受压3s(B组)、5s(C组)和10s(D组),制备新型挫伤型脊髓损伤模型;各组分别于术后1、3、7、14、21d观察其行为学评分和病理学改变;免疫组织化学方法检测促炎因子高迁移率族蛋白B1(HMGB1)在各组不同时间点的表达变化。结果:实验组各时间点BBB评分和损伤程度与对照组比较均有显著差异(P0.05),其中A组和B组术后损伤程度差别微小;C组后肢运动功能障碍明显,脊髓损伤区域出现典型的病理改变;D组损伤最严重,死亡率高。HMGB1表达以损伤C组为典型代表,术后阳性表达明显增多,第3d达高峰,主要表达部位为神经元胞浆和神经胶质细胞核内。结论:采用改良Allen法打击再受压5s制备的脊髓损伤模型能很好地模拟临床实际,且稳定性高、可复制性好,为一种新型挫伤型脊髓损伤模型。     

脊髓挫伤速度对颈脊髓原发性损伤影响的实验研究

目的　确定脊髓挫伤速度是脊髓损伤的因素,探讨不同速度的脊髓挫伤对大鼠颈脊髓原发性损伤的影响。  方法    20只成年雄性Sprague-Dawley大鼠随机分为快速组（500 mm/s,n=8）、慢速组（5 mm/s,n=8）和对照组（n=4）。用直径为4 mm的平头圆锥打击头在C5水平产生1.5 mm的挫伤位移。损伤后即行心脏固定,切取以挫伤部位为中心长约1.5 cm的脊髓组织。行连续矢状位冰冻切片。HE染色观察脊髓大体形态,计算出血量。β-APP免疫组化后观察轴索损伤程度。  结果　挫伤后观察到脊髓表面有一带状出血,且快速组出血带颜色更深。快速组挫伤位移为(1.50±0.05) mm,最大力为(5.3±1.2) N;慢速组挫伤位移为(1.51±0.04) mm,最大力为(2.8±0.6) N,两组间最大力的差异有显著性（P=0.001）。HE染色显示脊髓出血大部分都集中在灰质,白质相对较少。快速组脊髓总出血量、灰质出血量和白质出血量分别为0.94、0.71和0.23 mm3,慢速组分别为0.55、0.43和0.12 mm3,其中两组间总出血量和灰质出血量的差异有显著性（P＜0.05）。β-APP免疫组化观察到快速组轴索断裂比慢速组更为严重。  结论　脊髓挫伤速度是影响脊髓原发性损伤的因素,快速的脊髓挫伤导致的原发性脊髓损伤更为严重,导致更多的脊髓出血和轴索断裂。     

大鼠脊髓全横断损伤模型的建立

目前用于脊髓全横断的动物模型,常遗有部分未损脊髓组织,局部脊髓损伤范围很大,尤其是破坏了的血运扩大了继发性变性,造成了复杂的局部病理变化,致使难以分析治疗性脊髓伤区内移植的疗效。因此迫切需要一种还原论式的脊髓横断模型,本实验设计了一种切割辅以吸除的方法,可以在局部造成平均约0.6mm的清洁横断区,同时保存脊髓腹、背动脉及脊髓背静脉的大鼠脊髓横断模型,并用H.E.染色法、神经丝(NF)和胶质纤维酸性蛋白(GFAP)的免疫组织化学方法及生物素化的葡萄糖胺(BDA)的追踪方法检验损伤区及其两侧脊髓的组织反应。     

神经干细胞移植对小鼠脊髓损伤的影响

目的观察神经干细胞(NSCs)移植对脊髓损伤(SCI)小鼠功能恢复的影响。方法分离、培养、增殖和纯化E14-17d小鼠的NSCs,并通过免疫荧光法对其进行鉴定。将绿色荧光蛋白转基因小鼠的NSCs移植到小鼠脊髓损伤模型体内,术后进行行为学和病理学检测,观察小鼠功能恢复情况。运用改良Allen's法制备小鼠T10-T11脊髓损伤动物模型,动物分为假手术组(12只)、模型组(12只),治疗组(12只)和对照组6(12只)。治疗组每只小鼠自眶静脉注射NSCs悬液200μl(2×10个细胞),对照组只注射DMEM/F12培养基200μl。术后1d、3d、7d、14d、21d、28d和56d,进行BBB运动功能评分和病理学检测,观察植入区细胞生长变化情况。结果 BBB评分显示:治疗组明显高于对照组(<0.01),治疗组与假手术组相比没有明显差异(>0.05),说明NSCs移植后小鼠的行为学得到了明显改善,功能有所恢复。病理学检测发现,移植后NSCs不仅迁移到脊髓损伤区,而且与宿主细胞较好地整合。结论移植的E14-17d胚胎小鼠NSCs不仅可在脊髓损伤部位存活并和宿主细胞整合,而且可促进小鼠后肢运动功能恢复。     

小剂量超短波对脊髓损伤功能恢复及对血清iNOS、TNF-α、VEGF、BDNF表达的影响

目的　探讨小剂量超短波对脊髓损伤患者功能恢复效果及对血清诱导型一氧化氮合酶（iNOS）、肿瘤坏死因子-α（TNF-α）、血管内皮生长因子（VEGF）、脑源性神经营养因子（BDNF）表达的影响。 方法　收集60例脊髓损伤患者,随机分为治疗组与对照组,每组30例。对照组给予基础康复治疗,治疗组加用小剂量超短波治疗,共治疗3个疗程。评估疗效并分析影响脊髓功能恢复的因素。 结果　治疗组总有效率高于对照组（P<0.05）;康复治疗后,治疗组ASIA量表运动功能、感觉功能评分高于对照组（P<0.05）;血清VEGF、BDNF表达含量高于对照组（P<0.05）,iNOS、TNF-α表达含量低于对照组（P<0.05）;小剂量超短波治疗是脊髓损伤患者预后的保护因素（P<0.05）。 结论　小剂量超短波辅助治疗可明显促进患者脊髓功能恢复,其机制可能与下调血清iNOS、TNF-α表达,上调VEGF、BDNF表达有关。     

电针刺激对脊髓挫伤模型大鼠神经细胞凋亡的影响

BACKGROUND: Electroacupuncture has promoting effects on the functional recovery of the injured spinal cord, can decrease pain, and elevate postoperative effect after acute spinal cord contusion.  OBJECTIVE: To observe the effect of electroacupuncture on apoptosis in the injured site after spinal cord contusion, and analyze its neuroprotective effects on neurological function in rats with spinal cord contusion. METHODS: A total of 66 adult female Sprague-Dawley rats were randomly divided into: sham surgery group (n=20), spinal cord contusion group (n=20), electroacupuncture stimulation group (n=20) because six rats were excluded due to modeling failure and death. Before model establishment, at 1, 3 days, 1, 2, 3 and 4 weeks after model establishment, motor functions were evaluated by BBB score and the inclined plate test. At 3 days after model establishment, apoptosis of nerve cells could be detected in the site of injury in each experimental group using TUNEL assay. mRNA and protein expression of bax, bcl-2 and caspase-3 was detected surrounding the injury site using RT-PCR and western blot assay. Morphological changes in the site of injury could be observed using hematoxylin-eosin staining. The regeneration of nerve fibers was observed using HRP tracing.  RESULTS AND CONCLUSION: (1) Motor function score was significantly increased at various time points in the 2nd week of treatment in the electroacupuncture stimulation group than in the spinal cord contusion group (P < 0.05). (2) Apoptotic index was significantly lower in the electroacupuncture stimulation group than in the spinal cord contusion group at 3 days after model establishment (P < 0.05). (3) mRNA and protein expression of bax and caspase-3 was significantly lower in the electroacupuncture stimulation group than in the spinal cord contusion group at 72 hours (P < 0.05); bcl-2 gene and protein expression was significantly higher (P < 0.05). (4) The number of HRP-positive nerve fibers was highest in the sham surgery group, followed by electroacupuncture stimulation group, and lowest in the spinal cord contusion group at 4 weeks (P < 0.05). Results indicated that electroacupuncture plays a protective role on the spinal cord contusion by reducing apoptosis of nerve cells at the site of injury.      

小剂量超短波对脊髓损伤功能恢复及对血清iNOS、TNF-α、VEGF、BDNF表达的影响

目的　探讨小剂量超短波对脊髓损伤患者功能恢复效果及对血清诱导型一氧化氮合酶（iNOS）、肿瘤坏死因子-α（TNF-α）、血管内皮生长因子（VEGF）、脑源性神经营养因子（BDNF）表达的影响。 方法　收集60例脊髓损伤患者,随机分为治疗组与对照组,每组30例。对照组给予基础康复治疗,治疗组加用小剂量超短波治疗,共治疗3个疗程。评估疗效并分析影响脊髓功能恢复的因素。 结果　治疗组总有效率高于对照组（P<0.05）;康复治疗后,治疗组ASIA量表运动功能、感觉功能评分高于对照组（P<0.05）;血清VEGF、BDNF表达含量高于对照组（P<0.05）,iNOS、TNF-α表达含量低于对照组（P<0.05）;小剂量超短波治疗是脊髓损伤患者预后的保护因素（P<0.05）。 结论　小剂量超短波辅助治疗可明显促进患者脊髓功能恢复,其机制可能与下调血清iNOS、TNF-α表达,上调VEGF、BDNF表达有关。     

碘过量对小鼠脾脏影响的组织学研究

目的探讨碘过量对机体免疫功能的影响。方法Balb/c小鼠32只,雌雄各半,随机分为适碘组(NI)、5倍碘组(5HI)、10倍碘组(10HI)、50倍碘组(50HI)。给以不同浓度碘化钾水喂养6个月后,处死取脾脏,对脾脏的绝对重量、脾脏指数进行测量分析,对脾脏的组织学改变进行观察,并对小鼠脾脏白髓、边缘区的体密度进行测量分析。结果摄入低倍过量碘的小鼠脾脏未见明显形态学改变,随着过量碘倍数的提高,脾脏的组织学改变逐渐明显,且呈现功能活跃的表现。结论高倍过量碘摄入可引起小鼠免疫功能亢进。     

蛇菰多糖减轻急性脊髓挫伤模型大鼠的神经元损伤

目的 探讨蛇菰多糖(BPS)对神经自噬的调节及对急性脊髓挫伤(SCI)的治疗作用。方法 将大鼠分为假手术组(sham,n=10)、模型组(SCI,n=15,用改良Allen’s脊髓撞击法)和BPS干预组(BPS,n=45,灌胃给予低、中、高3个剂量14 d);用BBB评分评价运动功能;采用HE及Nissl染色法观察形态;蛋白质免疫印迹法检测自噬相关蛋白的表达变化。结果 与sham组相比,SCI组大鼠的BBB评分-时间变化曲线明显降低,损伤程度达重度(P<0.05);SCI的脊髓背侧白质和中央灰质均损伤严重,空洞明显;神经元数量明显减少,胞体结构不完整;SCI组第1、7、14天的LC3Ⅱ/Ⅰ和p62相对表达水平上调,其中第7天表达最高(P<0.05);而Beclin 1表达整体下调,于第7天表达最低(P<0.05);与SCI组比较,BPS组大鼠BBB评分曲线呈剂量依赖性明显增高;BPS组背侧白质和中央灰质空洞缩小,神经元数量多,形态完整;BPS组Beclin 1、LC3Ⅱ表达明显回升,而p62蛋白较SCI组下调(P<0.05)。结论 蛇菰多糖对大鼠具有明确的神经保...     

Interlimb reflexes following cervical spinal cord injury in man

Summary The reflex interconnection of lower and upper extremity muscles was investigated in subjects with chronic (> 1 year post-injury) lesions to the cervical spinal cord. Lower extremity mixed nerves were stimulated with single shocks or with brief trains of high-frequency stimuli of varying intensities. EMG from a number of lower and upper extremity muscles was recorded on magnetic tape for later analysis. In one population of spinal cord injury (SCI) subjects, single stimuli to lower extremity nerves resulted in muscle responses in both ipsi- and contralateral upper extremity muscles. The minimal response latency to a single shock was typically much less in muscles on the ipsilateral side than for contralateral upper extremity muscles. Application of brief trains of stimuli (for example, 2 stimulus pulses at 500 Hz) typically resulted in a large reduction in latency to the contralateral motor response, such that it was now approximately equal to the ipsilateral motor response latency. This decline in response latency was not gradual with increasing afferent input. Instead, the response occurred either early or late, but not at intermediate latencies. Stimuli which were subthreshold for evoking M-waves or H-reflexes were sometimes still adequate to evoke upper extremity motor responses. Once the threshold had been exceeded, the magnitude of the evoked response appeared to be independent of the stimulus magnitude. These reflex interconnections of lower and upper extremities were obtained only from subjects with chronic and motor-complete cervical spinal cord injury. No such interlimb responses were seen in control subjects, or in subjects who had recovered some motor function below the level of their injury, and were now considered to be motor-incomplete quadriplegics.     

白细胞介素-10通过乙二醛酶1影响脊髓钝挫伤大鼠运动功能的恢复

目的　用慢病毒介导的方法抑制白细胞介素-10（IL-10）的RNA,观察IL-10通过乙二醛酶1（GLO1）影响大鼠脊髓损伤后运动功能恢复。 方法　SD大鼠66只,采用Allen’s法制备脊髓钝挫伤（spinal cord contusion,SCC）模型,随机分为Sham组（n=9）、SCC组（n=27）、Vector组（n=15）和IL-10 SH组（n=15）,分别注射空质粒和包装IL-10 siRNA的质粒;每组再分为3 d、7 d和28 d 亚组。采用BBB（Basso,Beattie,Bresnahan）评分评估大鼠后肢运动功能;免疫组织化学和qRT-PCR技术定位和定量测定IL-10和GLO1的表达变化;用慢病毒包装的RNA构建IL-10的RNA干扰模型（IL-10-SH-LV）评估IL-10和GLO1在脊髓损伤后的功能,GeneMANIA生物信息学预测IL-10和GLO1的关系。 结果　SCC后大鼠双后肢截瘫,后肢运动功能消失,BBB评分在损伤后1 d,3 d,7 d,14 d逐渐恢复,但低于对照组。qRT-PCR结果显示IL-10在脊髓损伤后表达显著降低;SCC后,免疫组织化学结果显示IL-10主要在脊髓前角的神经元和神经胶质细胞中表达。慢病毒干扰IL-10的表达后,随着时间推移,GLO1表达增加,大鼠运动功能BBB评分也逐渐恢复。GeneMANIA结果显示GLO1和IL-10通过共表达的Hpd和Klk1c2、Kcns1、Proc相互作用。 结论　IL-10通过上调抗氧化应激因子GLO1的表达促进脊髓损伤大鼠运动功能恢复。     

Graded unilateral cervical spinal cord injury and respiratory motor recovery

We examined the potential contribution of ventromedial (VM) tissue sparing to respiratory recovery following chronic (1 mo) unilateral C2 spinal cord injury (SCI) in rats. Preserved white matter ipsilateral to the injury was quantitatively expressed relative to contralateral white matter. The ipsilateral-to-contralateral white matter ratio was 0 after complete C2 hemisection (C2HS) and 0.23 ± 0.04 with minimal VM sparing. Inspiratory (breath min⁻¹) and phrenic frequency (burst min⁻¹), measured by plethysmography (conscious rats) and phrenic neurograms (anesthetized rats) respectively, were both lower with minimal VM sparing (p < 0.05 vs. C2HS). Tidal volume also was greater in minimal VM sparing rats during a hypercapnic challenge (p < 0.05 vs. C2HS). In other C2 hemilesioned rats with more extensive VM matter sparing (ipsilateral-to-contralateral white matter ratio = 0.55 ± 0.05), respiratory deficits were indicated at 1 mo post-injury by reduced ventilation during hypercapnic challenge (p < 0.05 vs. uninjured). Anterograde (ventral respiratory column-to-spinal cord) neuroanatomical tracing studies showed that descending respiratory projections from the brainstem are present in VM tissue. We conclude that even relatively minimal sparing of VM tissue after C2 hemilesion can alter respiratory outcomes. In addition, respiratory deficits can emerge in the adult rat after high cervical SCI even when relatively extensive VM sparing occurs.     

被动运动对脊髓损伤大鼠后肢运动功能及骨骼肌的影响

目的　观察被动运动促进脊髓损伤（Spinal cord injury, SCI）大鼠后肢运动功能恢复和改善骨骼肌萎缩的影响;探讨脑源性神经营养因子（BDNF）对被动运动促进功能恢复和延缓肌萎缩的作用。 方法　将36只健康成年雌性SD大鼠随机分假手术组、对照组（未行运动）,被动运动组（损伤1周后开始被动运动,共4 周）。采用改良的Allen’s法制备SCI模型。术后1 d和1、2、3、4 周通过大鼠Basso-Beattie-Bresnahan(BBB)行为学评分检测各组大鼠的运动功能;术后5周,采用HE染色比较各组大鼠脊髓组织病理变化,观察大鼠后肢腓肠肌的横断面积、直径和形态变化。测量腓肠肌湿重、体重和肌湿重/体重,评价肌萎缩情况;采用Western blots检测腓肠肌中BDNF的表达变化。 结果　被动运动组运动功能明显高于对照组（P<0.05）。损伤5周后,对照组和被动运动组的脊髓组织失去正常形态,神经元数量减少,损伤区大量空洞形成,而被动运动组的变化较对照组轻。对照组腓肠肌湿重、肌湿重/体重、横断面积和直径下降,被动运动组改善上述肌萎缩情况（P<0.05）。与假手术组相比,对照组和被动运动组BDNF表达量增加（P<0.05）,其中被动运动组高于对照组（P<0.05）。 结论　被动运动可能是通过增加SCI后BDNF表达促进损伤后运动功能的恢复,并能有效改善失神经性肌萎缩。     

Activation of endothelial nitric oxide synthase following spinal cord injury in mice

Endothelial nitric oxide synthase (eNOS) plays a neuroprotective role after cerebral ischemia through the production of NO, which enhances cerebral blood flow. However, precise details regarding activation of eNOS after spinal cord injury (SCI) largely remain to be elucidated. In the present study we investigated chronological alteration and cellular location of eNOS and phosphorylated (p)-eNOS at Ser(1177) following SCI in mice. Western blot analysis showed eNOS to be significantly phosphorylated at Ser(1177) from 1 to 2 days after mild SCI, with gradual decrease thereafter. Immunohistochemistry revealed the p-eNOS to be mainly expressed in the endothelial cells of microvessels within gray matter under these conditions. These findings suggest that mild SCI activates eNOS in the subacute stage, which increases spinal cord blood flow and may be involved in protective and repair responses.     

小鼠海马结构与脊髓损伤后抑郁症高发病率的关系研究

目的:探究脊髓损伤引发的抑郁高风险率是否与海马生理结构的改变有关。方法:制作小鼠脊髓损伤模型,分别在损伤后不同时期采用Basso Mouse Scale(BMS)评分对小鼠术后运动功能进行评估;并通过糖水偏好实验和悬尾实验评估小鼠的抑郁情况;HE染色观察海马组织内部细胞的变化;电镜观察海马亚细胞结构突触的结构变化;RT-qPCR检测突触蛋白标志物突触小泡蛋白(SYP)和突触后致密蛋白95(PSD-95)在mRNA水平上的变化。结果:行为学实验显示模型组小鼠有显著的抑郁行为,且在第7天抑郁程度最显著(P<0.01);HE染色显示,与对照组相比,模型组海马细胞排列紊乱,数量减少,形态欠规则;电镜结果显示,与对照组相比,模型组海马超微结构突触数量减少,突触活动区长度变短,突触后致密物厚度变薄,突触间隙宽度增加,突触界面曲率减小(P<0.05);RT-qPCR结果显示模型组SYP和PSD-95 mRNA表达水平较对照组降低(P<0.05)。结论:海马生理结构的改变是脊髓损伤后抑郁症高风险的原因之一。     

c-Jun N-terminal kinase induces axonal degeneration and limits motor recovery after spinal cord injury in mice

C-Jun N-terminal kinase (JNK) mediates neuronal death in response to stress and injury in the CNS and peripheral nervous system. Here, we show that JNK also regulates retrograde axonal degeneration (axonal dieback) after spinal cord injury (SCI) in mice. Activated phospho-JNK was highly expressed in damaged corticospinal tract (CST) axons after thoracic SCI by hemisection. Local administration of SP600125, a JNK inhibitor, prevented accumulation of amyloid-β precursor protein and retraction of the severed CST axons as well as preserved the axonal arbors rostral to the injury site. The treatment with SP600125 also improved functional recovery of the hindlimbs, assessed by Basso mouse scale open-field scores and the grid-walking test. In Jnk1^−/− and Jnk3^−/− mice, we observed prevention of axonal degeneration and enhancement of motor recovery after SCI. These results indicate that both JNK1 and JNK3 induce axonal degeneration and limit motor recovery after SCI. Thus, a JNK inhibitor may be a suitable therapeutic agent for SCI.     

Nonlinear viscoelastic characterization of the porcine spinal cord

Although quasi-static and quasi-linear viscoelastic properties of the spinal cord have been reported previously, there are no published studies that have investigated the fully (strain-dependent) nonlinear viscoelastic properties of the spinal cord. In this study, stress relaxation experiments and dynamic cycling were performed on six fresh porcine lumbar cord specimens to examine their viscoelastic mechanical properties. The stress relaxation data were fitted to a modified superposition formulation and a novel finite ramp time correction technique was applied. The parameters obtained from this fitting methodology were used to predict the average dynamic cyclic viscoelastic behavior of the porcine cord. The data indicate that the porcine spinal cord exhibited fully nonlinear viscoelastic behavior. The average weighted root mean squared error for a Heaviside ramp fit was 2.8 kPa, which was significantly greater (p < 0.001) than that of the nonlinear (comprehensive viscoelastic characterization method) fit (0.365 kPa). Further, the nonlinear mechanical parameters obtained were able to accurately predict the dynamic behavior, thus exemplifying the reliability of the obtained nonlinear parameters. These parameters will be important for future studies investigating various damage mechanisms of the spinal cord and studies developing high-resolution finite elements models of the spine.