大鼠脊髓半横断损伤对脊髓versican、 CD44表达的影响

目的:观察大鼠脊髓半横断损伤(HSCI)对硫酸软骨素蛋白多糖versican及CD44在脊髓中表达的影响,为进一步探索脊髓损伤后的再生修复机制提供实验依据.方法:成年SD大鼠随机分为假手术对照组和HSCI 3、 7和14d组.建立成年大鼠HSCI(胸9～10)模型.取损伤位点头尾段胸9、胸10节段制作冷冻切片,用免疫组织化学ABC法和图像分析技术检测脊髓内versican和CD44的表达.结果:Versican阳性产物主要分布于细胞外基质中,腹角神经元和胶质细胞的胞质中也有分布;CD44阳性产物主要分布于细胞外基质及腹角神经元和胶质细胞的胞质中.损伤后脊髓内versican表达较对照组明显增加,CD44表达也较对照组明显增加.结论:HSCI后versican与CD44表达都增加,两者可能相互作用共同参与损伤后轴突生长被抑制这一过程.     

脊髓半横断损伤后trkB基因表达的变化

脊髓损伤后期trkB的变化及作用仍不清楚,本实验建立脊髓半横断损伤模型（hSCI）,术后14天取损伤脊髓用定量PCR测定trkB表达水平。结果显示,与假手术组比较,损伤脊髓trkB mRNA水平明显下调。推测trkB减少可能是不利于修复的因素之一,值得重视。     

脊髓半横断猕猴的护理

脊髓损伤（spinal cord injury,SCI）是脊柱骨折的严重并发症。有效的动物模型是脊髓损伤修复研究的基础。以往的研究都是建立在啮齿类动物上的,而人类神经系统生理结构及修复能力与啮齿类动物有很大不同。建立猴脊髓半横断（hemi-sected SCI,hSCI）和全横断（transected SCI,tSCI）脊髓损伤模型,更深入地研究脊髓损伤修复机理,为临床提供治疗脊髓损伤提供新的策略。动物模型建立之后,正确的护理是实验成功的必要环节,常常决定了实验的成败。为提高非人灵长类动物在脊髓损伤与修复研究中的成活率,本对实践中猴脊髓半横断损伤模型有效的护理经验进行了总结。     

大鼠脊髓半横断损伤对脊神经节P物质表达的影响

目的探讨脊髓半横断损伤对脊神经节P物质(SP)表达的影响。方法选取成年SD大鼠30只,随机分为5组,每组6只;实验组为4组,正常对照组为1组。实验组:脊髓右侧行半横断损伤,术后3、7、14和28d于各时间点分别取出损伤区手术侧脊神经节,石蜡切片后行免疫组织化学染色,结合图像分析技术观察SP在脊神经节内含量的变化。对照组不做任何处理,7d后检测同上。结果术后3d脊神经节内SP的阳性神经元数、阳性细胞百分率较对照组明显增多,7d组较3d组呈下降趋势,14d进一步下降,28d组SP的阳性神经元数、阳性细胞百分率逐渐回升,但仍低于正常对照组。结论脊髓半横断损伤可导致脊神经节SP表达改变,提示SP作为一种感觉神经的传导物质,可能在脊髓半横断损伤过程中发挥作用。     

脊髓半横断损伤后大鼠运动终板的氯化金染色研究

脊髓损伤(Spinal Cord Injury,SCI)是一种严重危害人类健康的疾病。SCI后,受脊髓支配的骨骼肌因失去脊髓的神经支配而废用及没有神经营养作用而发生萎缩,影响骨骼肌功能的恢复。临床或实验过程中经常需要确定肌肉组织神经支配情况。上运动神经元损伤后骨骼肌运动终板存在退变现     

神经生长因子及其高亲和力受体在脊髓损伤大鼠大脑运动皮质及皮质脊髓束的表达

目的探讨脊髓损伤后大脑运动皮质及皮质脊髓束内神经生长因子(NGF)及其高亲和力受体(TrkA)表达的变化。方法成年SD大鼠,随机分为正常对照组、假手术组、脊髓损伤(SCI)组。参照Allen重击法,重击SCI组动物T12节段脊髓背侧,顿挫损伤双侧皮质脊髓侧束,按损伤后存活时间将动物分为SCI 1d组、SCI 2d组、SCI 5d组。各组大脑及脊髓切片经ABC法免疫组织化学染色,光镜及电镜观察,并用图像分析技术对结果进行分析。结果脊髓损伤后上述部位酪氨酸蛋白激酶A(TrkA)的表达随SCI后动物存活时间的延长明显上调,电镜观察发现损伤后的皮质脊髓侧束轴浆内有TrkA免疫反应阳性产物积聚,轴膜上亦有免疫反应产物分布,且轴索末端有生芽现象;皮质脊髓侧束的神经纤维内可见串珠状的NGF免疫反应阳性产物,束内NGF阳性胶质细胞亦随动物术后存活时间的延长逐渐增多。结论脊髓损伤可刺激大脑相应区域运动皮质锥体细胞表达TrkA并向其轴突末梢运输定位于轴膜,以摄取损伤局部胶质细胞等产生的NGF,后者借逆向轴浆运输运回胞体,维持锥体细胞的存活及促进其轴突的再生。     

大鼠脊髓半横断损伤后硫酸软骨素蛋白多糖Versican的变化

目的观察大鼠脊髓半横断损伤(hSCI)位点头尾段硫酸软骨素蛋白多糖Versican的表达变化,探讨其与脊髓损伤修复的关系。方法20只成年健康SD大鼠随机分为假手术对照组和脊髓半横断损伤3d、7d和14d组。建立成年SD大鼠脊髓半横断(T9～T10)模型。取损伤位点头尾段T9、T10节段制作冰冻切片,运用Versican抗血清进行免疫组化ABC法染色。分别观察并计数各组前角中Versican阳性细胞数,采用计算机图像分析技术测量免疫阳性产物的平均光密度(A)值。结果Versican阳性产物主要分布于细胞外基质中,前角神经元和胶质细胞的胞浆中也有分布;损伤后前角中Versican阳性神经元和胶质细胞数较对照组明显减少(P<0.05),免疫阳性产物平均A值较对照组明显增加(P<0.05)。结论脊髓半横断损伤后,表达增加的Versican很可能参与损伤后轴突生长被抑制的过程。     

DiI顺行追踪大鼠皮质脊髓束

目的 用DiI追踪大鼠皮质脊髓束,探讨DiI在皮质脊髓束顺行追踪中的应用效果.方法 Wistar大鼠24只,随机分为DiI组和溃变组,于DiI组感觉运动区皮质表面涂布5%DiI;对溃变组则损毁相应的感觉运动区皮层.结果 DiI组术后存活5d的鼠,仅在端脑和间脑区见红色荧光标记的纤维,在术后存活10d、15d、20d的鼠脑及脊髓各节段内均可见红色荧光标记的皮质脊髓束纤维;溃变组在脊髓节段可观察到明显的溃变纤维,以术后存活5d最为显著,在脊髓以上节段未见明显溃变纤维.结论 采用DiI活体顺行追踪大鼠皮质脊髓束的方法简便易行,对于皮质脊髓束的示踪研究,尤其中脑以下节段的显示具有比较好的应用价值.     

嗅鞘细胞移植对脊髓半横断损伤大鼠后肢运动功能的影响

目的观察嗅鞘细胞移植物对脊髓半横断损伤大鼠后肢运动功能的影响。方法30只雌性成年SD大鼠制成脊髓半横断损伤模型,并随机分成5组立即进行移植,A组移植纯化的嗅鞘细胞(olfactory ensheathing cells,OECs)悬液,B组移植纯化的OECs培养上清液,C组移植未纯化的OECs,D组移植未纯化的OECs培养上清液,E组移植DMEM/F12培养液,术后6 w内进行BBB评分和IP实验,用单因素方差分析进行统计学分析。结果A组的BBB评分在3w后较其它组高,差异有统计学意义(P<0.05),A组的IP实验结果在4 w后较其它组高,差异有统计学意义(P<0.05)。结论纯化培养嗅鞘细胞移植能促进脊髓半横断损伤大鼠后肢运动功能恢复。     

脊髓半横断损伤后p53基因表达的变化

脊髓损伤亚急性期p53的表达变化仍不清楚,本实验建立脊髓半横断损伤（hSCI）大鼠模型,用定量PCR探讨脊髓p53基因水平变化,结果发现,术后14天,损伤脊髓p53基因表达明显下调。提示p53参与了hSCI损伤修复过程,值得重视。     

Neuroprotective action of bacterial melanin in rats after corticospinal tract lesions

Experiments were performed on 48 albino rats. Part of the experimental animals were initially trained to a balancing instrumental conditioned reflex (ICR). Unilateral bulbar pyramidotomy performed in all rats caused contralateral hemiparesis. On the next day following the operation 24 rats were injected intramuscularly with bacterial melanin solution. 12 of these rats were initially trained to ICR. Recovery periods of ICR and paralyzed hindlimb movements were registered for melanin injected rats (n=24) and for operated rats, not treated with melanin (n=24). In rats injected with bacterial melanin the posttraumatic recovery is shorter than in animals not treated with melanin. The fastest and complete recovery was registered in rats initially trained to ICR and injected after the operation with bacterial melanin. Electrophysiological experiments were performed in transected animals treated with melanin, transected animals without melanin treatment and intact animals. Spiking activity of motoneurons was registered in lumbar motoneurons of rats in response to high frequency stimulation above the corticospinal tract transection. Spiking activity was very similar in motoneurons of melanin injected and intact or non operated animals. In animals, not dosed with bacterial melanin after the operation, areactivity or no change in firing rate was registered in response to stimulus. Stimulation of the corticospinal tract of melanin injected rats produced potentiation of the motoneuronal firing rate and is an evidence of regeneration in corticospinal tract. Similarity in spiking activity of intact and melanin injected rats shows the recovery of conductance in pyramidal tract. Morphohistochemical examination was carried out to confirm the results of behavioral and electrophysiological experiments. Medulla slices were prepared to trace the regeneration of nerve fibers. Examination of transection area revealed that bacterial melanin increases vascularization, dilates the capillaries in nervous tissue and stimulates the process of sprouting.     

Conditioned H-reflex increase persists after transection of the main corticospinal tract in rats

The brain shapes spinal cord function throughout life. Operant conditioning of the H-reflex, the electrical analog of the spinal stretch reflex (SSR), is a relatively simple model for exploring the spinal cord plasticity underlying this functional change and may provide a new method for modifying spinal cord reflexes after spinal cord injury. In response to an operant conditioning protocol, rats can gradually increase (i.e., up-training mode) or decrease (i.e., down-training mode) the soleus H-reflex. This study explored the effects of midthoracic transection of the ipsilateral lateral column (LC) (rubrospinal, vestibulospinal, and reticulospinal tracts), the dorsal column corticospinal tract (CST), or the dorsal column ascending tract (DA) on maintenance of an H-reflex increase that has already occurred. Rats were implanted with EMG electrodes in the right soleus muscle and a nerve-stimulating cuff on the right posterior tibial nerve. After initial (i.e., control) H-reflex size was determined, the rats were exposed for 50 days to the up-training mode, in which reward was given when the H-reflex was above a criterion value. H-reflex size gradually rose to 168 +/- 12% (mean +/- SE) of its initial value. Each rat then received an LC, CST, or DA transection and continued under the up-training mode for 50 more days. None of the transections abolished the H-reflex increase. H-reflex size increased further to 197 +/- 19% of its initial value and did not differ significantly among LC, CST, and DA rats (P > 0.78 by ANOVA). Although earlier studies show that the main CST is needed for acquisition of H-reflex up-training and down-training and for maintenance of down-training, this study shows that it is not needed for maintenance of up-training. It adds to the evidence that H-reflex conditioning changes the spinal cord and that the spinal cord plasticity associated with up-training is different from that associated with down-training.     

Ultrastructural changes in the sperm-tail of zinc-deficient rats

Young male rats were fed a diet containing less than 1 mg per kg zinc for 40 days and developed severe atrophy of the seminiferous tubules. The tails of the spermatids and spermatozoa within these tubules were often malformed. The most common abnormality was the absence of one or more of the microtubular components of the axonemes. Pronounced abnormalities of the axoneme were usually accompanied by disruption of the sheath of accessory fibres. These changes are compared with those arising from other experimental treatments and their aetiology is discussed in relation to the possible involvement of zinc in the assembly of microtubules.     

RYK在小鼠皮质脊髓束神经通路发育过程中的表达变化

目的观察RYK在皮质脊髓束发育投射通路中的表达情况,为进一步研究RYK在其中的功能提供重要线索。方法通过原位杂交和免疫荧光组织化学法,分别检测了E14.5、E16、E18.5和出生后P3、P5、P7等不同时间点RYK在小鼠大脑运动皮层和皮质脊髓束神经通路中的表达情况。结果RYK的表达出现在胚胎E18.5 d运动皮层神经元中,到P0时逐渐增强并表达在脑内投射的皮质脊髓束神经通路,从P0~P5,RYK持续表达在皮质脊髓束在脑内和脊髓的整个神经通路上,而后逐渐减弱。结论RYK的表达与皮质脊髓束神经通路在脊髓中的发育投射有密切关系。     

Ultrastructural changes in the supraoptica-neurohypophyseal system after induction of lesions in the pituitary stalk in rats

Fine structural changes occurring in the supraoptic nucleus and the neural lobe have been studied in rats following the electrolytic lesion of the hypophysial stalk. Supraoptic neurosecretory neurones undergo a typical chromatolytic reaction. In addition, proliferating microglial cells disconnect axosomatic synapses and phagocytose degenerating neurones. Surviving neurones show signs of structural restitution 3 to 4 weeks after surgery. In the neurohypophysis degeneration of secretory nerve endings started with the disintegration of secretory vesicles 3 to 4 d postoperatively. Degenerated axon terminals were engulfed by pituicytes. Signs indicative of axonal regeneration were not observed in the neural lobe up to the end of the 4th postoperative week.     

大鼠坐骨神经超微结构的老年性变化

为了研究老年大鼠坐骨神经超微结构特点,随机取3月龄(成年组)和24月(老年组)龄正常SD大鼠各10只,用电镜观察两组间坐骨神经超微结构的差异。结果显示:老年组大鼠坐骨神经内有髓纤维的百分比、轴突间胶原纤维密度以及Schwann细胞胞质中脂褐质沉积密度均多于成年组(P<0.05);但无髓纤维之百分比少于成年组(P<0.05)。上述结果提示坐骨神经内的有髓纤维与无髓纤维百分比、轴突间胶原纤维密度以及Schwann细胞胞质中脂褐质沉积密度是衡量大鼠坐骨神经老化的形态标志之一。