大鼠肢体IRI后脊髓神经元Fos的表达

目的探讨脊髓神经元是否参与肢体缺血再灌注损伤（IRI）的发病过程以及有关神经元的分布特点。方法Wistar大鼠24只,随机分为4组,A：空白对照组;B：假手术对照组;C：单纯缺血组;D：缺血再灌注组。通过暂时阻断一侧髂总动脉和股动脉,建立肢体缺血再灌注损伤模型。采用免疫细胞化学ABC法,观察大鼠脊髓神经元原癌基因c—fos的表达和分布特点。结果大鼠肢体缺血4h,脊髓相应节段神经元Fos表达活跃。再灌注2h后,Fos表达更加活跃（P〈0．01）。并且Fos阳性神经元较集中分布于脊髓相应节段同侧后角及中央管周围。结论脊髓相应节段同侧神经元可能参与肢体IRI的发病过程,尤其是脊髓后角及中央管周围神经元可能具有更为重要的作用。     

Administration of bovine superoxide dismutase prevents sequelae of spinal cord ischemia in the rabbit

Summary The contribution of free radical-mediated reperfusion injury to the ischemic damage caused by total arterial occlusion has been investigated in a model of transient spinal cord ischemia in the rabbit. Spinal cord ischemia was produced in 20 anaesthetized rabbits by temporary luminal occlusion (20 min) of the abdominal aorta below the renal arteries. Superoxide dismutase (5 mg/kg) (10 animals) was infused before and during reperfusion below aortic occlusion using an infusion pump that infused the enzyme through the contralateral femoral artery. Control (10 animals) received sterile saline with the same procedure. In this later group, 4 animals developed paraplegia, 4 were paretic and only 2 were normal. However, in the treated group, 6 animals were normal while 3 were paretic and only one appeared paralyzed. We conclude that: a) oxygen free radicals generated during reperfusion are involved in producing the ischemic injury, and b) the ischemic spinal cord injury is prevented by superoxide dismutase.     

Selective occlusion of lumbar arteries as a spinal cord ischemia model in rabbits

Paraplegia is a devastating complication of operations requiring transient occlusion of the descending thoracic aorta. Many animal models of spinal cord ischemia have been utilized to examine the efficacy of various neuroprotective methods. In this study, we establish a rabbit model of spinal cord ischemia by selective temporary occlusion of lumbar arteries and examine the protective effects of systemic mild hypothermia in this model. Animals were divided into the following four groups: sham group (group A, n = 6); 10 min ischemia, normothermia (39 degrees C) (group B, n = 6); 20 min ischemia, normothermia (group C, n = 6); and 30 min ischemia, mild hypothermia (35 degrees C) (group D, n = 6). After 7 d of reperfusion, three rabbits in group B and five rabbits in group C developed paraplegia (Tarlov's score = 0). In contrast, all rabbits preserved hindlimb motor function (Tarlov's score = 4) in groups A and D. Histological findings indicated that the number of motor neurons in the anterior horns in group C were significantly fewer than in group A. A large number of motor neurons were preserved in group D. Hypothermia is known to be an effective and reliable method of neuroprotection, but the risk of complications rises at deep hypothermia. Our current results confirm that systemic, mild hypothermia is a safe and effective neuroprotective method during ischemia-reperfusion injury of the spinal cord.     

Accelerated functional recovery and neuroprotection by agmatine after spinal cord ischemia in rats

Treatment with agmatine, decarboxylated arginine, proved to be non-toxic and to exert neuroprotective effects in several models of neurotoxic and ischemic brain and spinal cord injuries. Here we sought to find out whether agmatine treatment would also prove beneficial in a rat spinal cord ischemia model (balloon occlusion of the abdominal aorta bellow the branching point of the left subclavian artery for 5 min). Agmatine was injected (100 mg/kg, i.p. ) 5 min after beginning of re-perfusion and again once daily for the next 3 post-operative days. Motor performance ('combined motor score') was recorded for up to 17 days post-operative and motoneuron cell counts (in representative spinal cord sections) performed on the 17th post-operative day. Agmatine treatment was found to accelerate recovery of motor deficits and to prevent the loss of motoneurons in the spinal cord after transient ischemia. Together, the present and previous findings demonstrate that agmatine is an efficacious neuroprotective agent and that this naturally occurring non-toxic compound should be tried for therapeutic use after neurotrauma and in neurodegenerative diseases.     

右美托咪定在大鼠脊髓缺血再灌注损伤中的 保护作用及机制研究

目的 探讨右美托咪定对大鼠脊髓缺血/再灌注损伤的保护作用及PI3K/Akt传导通路在其中的作用。方法 30只成年雄性大鼠随机分为假手术组、模型组和右美托咪定治疗组,每组10只。建立大鼠脊髓缺血/再灌注损伤模型,对再灌注损伤后6 h、12 h、24 h、48 h实验大鼠后肢运动功能进行评分,检测缺血脊髓前角组织中P-AKT的表达水平及神经元的凋亡指数。结果 右美托咪定可改善脊髓缺血/再灌注损伤后实验大鼠的后肢运动功能(P＜0.05);提高脊髓前角P-AKT的表达水平(P＜0.05),抑制缺血/再灌注损伤所致的脊髓神经元的凋亡(P＜0.05)。结论 右美托咪定对脊髓缺血/再灌注损伤有一定的保护作用,其机制可能与激活PI3K/Akt传导通路,从而抑制神经元的凋亡有关。     

脊髓血供及其监测研究

本文主要对脊髓的血供及目前的用于监测脊髓血供的方法和未来可能应用的新技术做一个综述,旨在协助临床脊柱外科医生能更好地对脊髓血供进行监测,预防脊髓缺血的发生,减少脊髓缺血所引起的损伤。     

Morphofunctional changes in the rat spinal cord after focal photothrombosis

The aim of the present work was to study pathomorphological and functional changes after induced focal photothrombosis of blood vessels in the thoracic part of the spinal cord in rats. Neuron abnormalities characteristic of ischemia were seen at the focus of experimental photothrombosis and in the transitional zone, along with symptoms of impaired motor and pelvic organ function. The focal photothrombosis method can be used to model spinal cord ischemia for the development of pharmacological correction methods and the recovery of impaired sensorimotor functions. Translated from Morfologiya, Vol. 133, No. 1, pp. 35–38, January–February, 2008.     

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。     

周围神经缺血再灌注损伤动物模型的改良

目的研究周围神经缺血再灌注损伤动物模型的改良与建立。方法采用无损伤动脉夹暂时阻断大鼠一侧髂总动脉起始处血流,同时夹闭髂内、髂外动脉,一段时间后打开动脉夹,观察不同缺血再灌注时间下动物肢体功能情况,以及周围神经缺血导致的脊髓电镜下超微结构的改变,明确改良动物模型的实验效果。结果缺血时间的延长动物后肢的瘫痪症状逐渐加重。电镜观察脊髓神经元显示随再灌注时间的延长,神经元损害明显加重。结论用无损伤动脉夹阻断一侧髂总动脉和髂内、髂外动脉的周围神经缺血再灌注损伤的动物模型是对以往模型的改良。该模型制备操作简单,对动物的损伤更小,可得到理想的实验效果。     

Arterial Blood Supply to the Spinal Cord in Animal Models of Spinal Cord Injury. A Review

Animal models are used to examine the results of experimental spinal cord injury. Alterations in spinal cord blood supply caused by complex spinal cord injuries contribute significantly to the diversity and severity of the spinal cord damage, particularly ischemic changes. However, the literature has not completely clarified our knowledge of anatomy of the complex three‐dimensional arterial system of the spinal cord in experimental animals, which can impede the translation of experimental results to human clinical applications. As the literary sources dealing with the spinal cord arterial blood supply in experimental animals are limited and scattered, the authors performed a review of the anatomy of the arterial blood supply to the spinal cord in several experimental animals, including pigs, dogs, cats, rabbits, guinea pigs, rats, and mice and created a coherent format discussing the interspecies differences. This provides researchers with a valuable tool for the selection of the most suitable animal model for their experiments in the study of spinal cord ischemia and provides clinicians with a basis for the appropriate translation of research work to their clinical applications. Anat Rec, 300:2091–2106, 2017. © 2017 Wiley Periodicals, Inc.     

碱性成纤维细胞生长因子对脊髓缺血／再灌注损伤的保护作用

目的观察碱性成纤维细胞生长因子（basic fibroblast growth factor,bFGF）对脊髓缺血／再灌注损伤的保护作用。方法建立大鼠脊髓缺血／再灌注损伤动物模型。实验分对照组、缺血／再灌注组和bFGF组。测定血浆丙二醛、肌酸磷酸激酶、谷草转氨酶和乳酸脱氢酶含量。测定脊髓标本丙二醛、内皮素、细胞线粒体钙含量和组织湿／干重比值。结果缺血／再灌注组与对照组比较,血浆和脊髓的各项生化指标显著增高（P〈0．05）;使用bFGF后,血浆及脊髓各项测定指标较缺血／再灌注组相比明显降低（P〈0．05）。结论bFGF可减轻脊髓缺血／再灌注损伤,对脊髓有保护作用。     

Central thermosensitivity in conscious goats: Hypothalamus and spinal cord versus residual inner body

Experiments were performed on conscious goats to confirm the suggestion that in this species the inner body contains more thermosensitive structures than those residing in the hypothalamus and spinal cord. For this purpose goats were chronically implanted with local thermodes and intravascular heat exchangers to allow independent temperature control of the hypothalamus, spinal cord and residual inner body. With the hypothalamus and spinal cord clamped simultaneously at different levels between 32°C and 40°C, residual internal temperature was lowered by subtracting heat via the intravascular heat exchanger. The residual internal temperature at which shivering and increased heat production occured due to heat extraction, was directly related to the value of the combined hypothalamic and spinal cord clamp temperature. The higher hypothalamic and spinal cord clamp temperatures were, the lower residual internal temperature fell before shivering occurred and heat production rose. Plosts relating residual internal temperature to hypothalamic and spinal cord temperature at different levels of heat production showed the signal input generated within the residual inner body to be of nearly the same order of magnitude as that from the hypothalamus and spinal cord.This work was supported by DFG Je 57/3.     

Bradykinin preconditioning induces protective effects on the spinal cord ischemic injury of rats

The study was performed to investigate the effects of bradykinin preconditioning on spinal cord ischemic injury using an in vivo transient spinal cord ischemia model in rats. Prior to ischemia, bradykinin was infused continuously via the left femoral artery starting 15min before ischemia. Neurological functions were evaluated for 7 days postoperatively using modified Tarlov's scores. Tarlov's score outcomes showed a marked improvement in the bradykinin group compared to the ischemia group. The blood-spinal cord barrier (BSCB) permeability was also decreased by bradykinin preconditioning after 72 h reperfusion focal spinal cord in rats, which was greatly reversed by B9430 (bradykinin B2 receptor antagonist). Immunohistochemical and Western blot analysis of spinal cords revealed a significant increase in basic fibroblast growth factor protein (bFGF) levels. The study demonstrated that bradykinin preconditioning induces protection against spinal cord ischemic injury, and this protection is likely due to the protection of the vasculature of the spinal cord and the promotion of neuronal survival.     

缺血后处理对兔缺血/再灌注损伤脊髓的保护作用可能与PI3K/Akt信号有关

目的 探讨缺血后处理对兔缺血/再灌注损伤脊髓的保护作用及PI3K/Akt传导通路在其中的作用.方法 42只日本大耳白兔(2-2.5kg),随机分为7组,分别为缺血组(Ⅰ组);缺血后处理组(PB组);PB+DMSO组(D组);PB+Ly294002 5μg组(PY5组);PB+LY294002 10μg组(PY10组);...     

A Three-Dimensional Finite Element Model of the Cervical Spine with Spinal Cord: An Investigation of Three Injury Mechanisms

The spinal cord may be injured through various spinal column injury patterns (e.g., burst fracture, fracture dislocation); however, the relationship between column injury pattern and cord damage is not well understood. A three-dimensional finite element model of a human cervical spine and spinal cord segment was developed, verified using published experimental data, and used to investigate differences in cord strain distributions during various column injury patterns. For a transverse contusion injury, as would occur in a burst fracture, a 33% canal occlusion resulted in two peaks of strain between the indentor and opposing vertebral body and intermediate peak strain values. For a distraction injury, relevant to column distortion injuries, a 2.6 mm axial displacement to the cord resulted in more uniform strains throughout the cord and low peak strain values. For a dislocation injury, as would occur in a fracture dislocation, an anterior displacement of C5 corresponding to 30% of the sagittal dimension of the vertebral body resulted in high peak strain values adjacent to the shearing vertebrae and increased strains in the lateral columns compared to contusion. This model includes more anatomical details compared to previous studies and provides a baseline for mechanical comparisons in spinal cord injury.     

Different susceptibility of facilitatory and inhibitory spinal pathways to ischemia in the cat

The sensitivity of different excitatory and inhibitory segmental reflex pathways to ischemia was investigated by monosynaptic reflex testing in the spinal cat. Spinal cord ischemia was established by aortal snare occlusion of 1-10 min duration. Excitatory and inhibitory spinal pathways showed statistically significant different susceptibility to ischemic impact. In the period of decreasing responses after the onset of ischemia the transmission through oligo- or polysynaptic, facilitatory or inhibitory pathways was found to be depressed earlier than that of monosynaptic pathways. The period from the end of ischemia until the beginning of recovery of reflex effects was significantly longer for inhibitory effects, compared to the monosynaptic reflexes alone.The results indicated that interneurones of excitatory segmental pathways may be less sensitive to ischemia than motoneurones, and motoneurones seem to be less sensitive to ischemia than interneurones of inhibitory pathways. In high spinal animals, with a relatively high level of extensor inhibition, the enhanced excitability of inhibitory interneurones to GS motoneurones may be responsible for their sensitivity to ischemia, due to an increased rate of O(2) consumption and exhaustion of high-energy phosphate resources.     

Theoretical evaluation of a simple cooling pad for inducing hypothermia in the spinal cord following traumatic injury

The Pennes bioheat equation and finite element method (FEM) are used to solve for the temperature distributions in the spinal cord and cerebrospinal fluid (CSF) during 30 min of cooling for spinal cord injury (SCI) patients. The average CSF and spinal cord temperatures are reduced by 3.48 and 2.72°C, respectively. The 100-mm wide pad provides the desired cooling and uses the least amount of material. The presence of zero-average CSF oscillation under normal conditions decreases the cooling extent in the spinal cord due to the introduction of warm CSF surrounding the spinal cord. The temperature decrease in the spinal cord is more than doubled when the temperature at the back of the torso is lowered from 20 to 0°C. Spinal cord ischemia, often observed after traumatic spinal cord injury, promotes cooling penetration. The proposed technique can reduce the spinal cord temperature by 2°C within 30 min and may be a feasible treatment for traumatic SCI.     

Visualization of protein aggregation in nerve cells after ischemia/reperfusion by ubiquitin immunohistochemistry and impregnative Nauta method

Using ubiquitin immunohistochemistry and impregnative Nauta method we demonstrated that ubiquitin positivity and Nauta positivity in the neurons affected with ischemic injury in the lumbosacral spinal cord of rabbits and dogs may be of the same origin. Increased number of ubiquitin-positive aggregates was found in the cytoplasm of neurons in the intermediate zone and lamina IX of ventral horns of spinal cord in rabbits after 30 min of ischemia followed by 24 h lasting reperfusion. Nauta-positive, flocculent, intracytoplasmic, dark clusters appeared in the same localization in the canine lumbosacral spinal cord neurons after 30 min of ischemia and 24 h of reperfusion. Ubiquitin aggregates and Nauta-positive dark clusters in the injured spinal cord neurons could be the first light microscopic signs of slow neuronal death following spinal cord ischemia and reperfusion.     

他克莫司后处理诱导缺血脊髓对再灌注损伤的耐受*

目的探讨他克莫司后处理能否诱导大鼠缺血脊髓对再灌注损伤的耐受。方法成年雄性SD大鼠30只,随机分为假手术（s0）组、缺血再灌注（IR）组和他克莫司后处理（TP）组,每组10只大鼠,采用经股动脉置管球囊扩张制备脊髓缺血模型,SO组仅行置管,IR组在脊髓缺血20分钟后行再灌注,TP组在脊髓缺血20分钟后再灌注,即刻经左颈总动脉一次性注射他克莫司0．5mg／kg。再灌注后7、14天采用Tarlov评分法检测大鼠后肢运动功能,脊髓组织切片HE染色观察病理学改变。结果SO组大鼠各时间点后肢Tarlov评分均为5分,形态学检测显示脊髓组织结构正常;IR组大鼠Tarlov评分明显降低,脊髓组织呈现出坏死、水肿、空腔形成等缺血再灌注损伤表现;TP组大鼠Tarlov评分结果显著优于IR组,脊髓组织病理变化较IR组为轻。结论建立大鼠脊髓缺血再灌注损伤模型,并初步证实他克莫司后处理能诱导缺血脊髓对再灌注损伤的耐受。