脊髓损伤及其继发损伤时的兴奋性氨基酸含量变化

采用Ａｌｌｅｎ’ｓ打击法以５０ｇ／ｃｍ和１００ｇ／ｃｍ致伤大鼠脊髓，于伤后１０分钟、１小时、２小时、４小时、８小时、２４小时取伤段脊髓，用氨基酸微量检测技术测定天冬氨酸（ＡＳＰ）和谷氨酸（Ｇｌｕ）含量。结果显示：脊髓损伤（ＳＣＩ）后１０分钟两个致伤组ＡＳＰ、Ｇｌｕ均较对照组（单纯椎板切除无损伤）明显升高；但伤后１～２４小时两组ＡＳＰ较对照组明显降低，其中２小时和２４小时降低最显著，ＡＳＰ在８小时虽也降低，但较２小时略回升；５０ｇ／ｃｍ组伤后１小时、４小时、８小时Ｇｌｕ含量较１０分钟时降低，但仍高于对照组。１００ｇ／ｃｍ组伤后２小时、２４小时Ｇｌｕ降低最明显。结果表明ＳＣＩ后兴奋性氨基酸ＥＡＡ存在两个高低不同的反应峰，提示ＥＡＡ参与了ＳＣＩ后的继发性损伤。     

脑弥漫性轴索损伤的CT诊断价值

目的：探讨脑弥漫性轴索损伤（ＤＡＩ）的ＣＴ诊断价值。方法：对１９例临床表现符合ＤＡＩ的病例ＣＴ表现特点进行分析。结果：ＣＴ表现双侧脑实质大片状低密度区、皮髓质界限不清，第三脑、侧脑室及基底池对称性受压，中线结构未移位，脑实质内点状、斑片状出血灶。结论：ＣＴ表现结合临床，能对ＤＡＩ作出正确诊断，ＣＴ是ＤＡＩ首选检查方法。     

弥漫性轴突损伤的磁共振氢谱的变化

弥漫性轴突损伤(Diffuse axonal injury，DAI)普遍存在于各种程度的颅脑损伤中。脑白质中轴突的广泛断裂在重型颅脑损伤病例占50％以上，而在轻度颅脑损伤中仍占30％，检查轴突损伤在了解外伤性脑损害中具有重要的意义。但是如何在活体中检测轴突的病理改变相当困难，虽然明显的病理改变能被传统的影像学(CT或T1、T2加权像MRI)证实，     

弥漫性轴突损伤形态学改变的实验研究

目的　观察弥漫性轴突损伤的常见部位, 病理改变过程, 以及其发生原因和机制。探讨其与临床的相关性。方法　用 Ｍａｒｍａｒｏｕ 的落体打击装置致伤动物, 大鼠脑组织标本在光镜和电镜下观察。结果　轴突回缩球密度在桥脑基底部和小脑上脚最高。伤后轴突内的微丝、微管结构紊乱, 轴突肿胀。伤后３ 天, 多数肿胀的轴突断裂, 形成轴突回缩球。１ 小时组轴突内钙颗粒数量是对照组的１７ 倍, 提示钙的内流。结论　本实验中弥漫性轴突损伤的最常见部位是桥脑基底部和小脑上脚。轴突损伤的过程为： 轴突内结构的紊乱, 轴突肿胀及断裂。轴突损伤的主要发生原因和机制可能是细胞外钙的内流。在伤后１２ 小时以内, 损伤轴突尚未断裂, 可能仍存在可逆性, 这可能是临床上有效治疗的最佳时机。     

大鼠急性脑损伤后脑局部代谢磁共振波谱分析

目的：本实验研究鼠急性颅脑损伤局部脑组织代谢的情况，以找出颅脑损伤与恢复过程中局部脑组织各种代谢成分变化的规律。方法：采用自由落体致鼠脑损伤模型，伤后３０分钟、３、２４、１６８小时取材，用核磁共振波谱法分析颅脑损伤局部脑组织代谢的变化。各组间采用ｔ检验。结果：颅脑损伤后伤区脑组织乳酸含量于伤后３小时已显著增高（Ｐ＜０．０１），伤后２４小时仍然明显高于正常。胆碱于伤后３小时已有明显升高，２４小时达高峰（Ｐ＜０．０１）。Ｎ－乙酰门冬氨酸含量自伤后３小时明显降低，伤后２４～１６８小时仍然显著低于正常（Ｐ＜０．０１）。谷氨酸自伤后３０分钟开始明显降低，３小时降到最低水平（Ｐ＜０．０１）。结论：实验表明颅脑损伤后３小时伤区脑组织已显著呈缺血性改变，伤后２４小时达高峰。     

脑弥漫性轴索损伤的CT及临床：（附382例分析）

目的探讨脑弥漫性轴索损伤（ＤＡＩ）的ＣＴ及临床特征诊断正确性。方法对３８２例ＤＡＩ的临床及ＣＴ改变特点作回顾性分析。结果“脑剪应力伤”是ＤＡＩ的病理改变核心。轴索神经微丝断裂病人伤后即刻昏迷并呈持续状态，ＧＣＳ计分≤８是ＤＡＩ临床特点。弥漫性脑密度减低伴散在性小点片状出血灶，脑室变小，脑池变形或消失是ＤＡＩ特征性ＣＴ表现。结论ＣＴ检查是诊断ＤＡＩ有效非创伤性方法，典型临床及ＣＴ表现是诊断ＤＡＩ的依据。     

弥漫性轴索损伤

弥漫性轴索损伤（ｄｉｆｕｓｅａｘｏｎａｌｉｎ－ｊｕｒｙ,ＤＡＩ）,是在特殊的外力机制作用下,脑内发生的以神经轴索断裂为特征的系列病理生理变化,意识障碍是其典型临床表现,诊断和治疗困难,预后极差。本文对ＤＡＩ近年来研究进展予以综述。一、生物力学机制脑内...     

弥漫性轴突损伤的概念和病理机制

所有不同伤情颅脑伤患者脑组织的显微镜病理形态学检查都存在共同特征：轴突损伤。1956年，Strich首先提出了大脑白质弥漫性变性的概念，80年代被正式命名为弥漫性轴突损伤（diffuse axonal injury，简称DAI），并被国际学术界所公认。     

急性闭合性颅脑损伤患者血清髓鞘碱性蛋白及其抗体含量的研究

用酶联免疫吸附法（ＥＬＩＳＡ）测定３６例急性闭合性颅脑损伤（ＡＣＨＴ）患者、４０例其它神经系统疾病（ＯＮＤ）患者及３２名正常人的血清髓鞘碱性蛋白（ＭＢＰ）及其抗体（Ａｎｔｉ－ＭＢＰ）含量。结果表明：ＡＣＨＴ组患者血清ＭＢＰ含量显著高于ＯＮＤ组与正常人组（均Ｐ＜０．０１），ＡＣＨＴ患者中脑挫裂伤组和脑内血肿组血清ＭＢＰ含量较脑震荡组明显增高（均Ｐ＜０．０１）；而ＯＮＤ组与正常人组比较则无明显差异（Ｐ＞０．０５）。ＡＣＨＴ组患者血清Ａｎｔｉ－ＭＢＰ含量与ＯＮＤ组比较差别无显著性（Ｐ＞０．０５）。提示血清ＭＢＰ含量对判断颅脑损伤的病情有重要价值。     

急性闭合性颅脑损伤患者血清髓鞘碱性蛋白及其抗体含量的…

用酶联免疫吸附法（ＥＬＩＳＡ）测定３６例急性闭合性颅脑损伤（ＡＣＨＴ）患者、４０例其它神经系统疾病（ＯＮＤ）患者及３２名正常人的血清髓鞘碱性蛋白（ＭＢＰ）及其抗体（Ａｎｔｉ－ＭＢＰ）含量。结果表明：ＡＣＨＴ组患者血清ＭＢＰ含量显著高于ＯＮＤ组与正常人组（均Ｐ〈０．０１），ＡＣＨＴ患者中脑挫裂伤组和脑内血肿组血清ＭＢＰ含量较脑震荡组明显增高（均Ｐ〈０．０１）；而ＯＮＤ组与正常人组比较则无明显差异（Ｐ     

Extent of nerve cell injury in Marmarou's model compared to other brain trauma models

OBJECTIVES: We sought to determine the extent of nerve cell injury in the Marmarou's acceleration impact model of diffuse brain injury. METHODS: Sensitive markers for cell injury including immunostaining for beta-amyloid precursor protein (beta-APP, a marker for diffuse axonal injury, DAI), Fluoro-Jade (FJ) histochemistry and electron microscopy (EM) were used in sham-operated and traumatized brains. RESULTS: APP immunostaining confirmed and extended previous findings of DAI in association and subcortical fiber systems in the white matter after injury. Increasing FJ labeling of neurons in layers II-III of sensorimotor cortex (smCx) from 4 to 48 hours after trauma and scattered labeled cells were found in the lower cortical layers. EM confirmed the presence of dystrophic pyramidal neurons in layers II-III of smCx 24 and 48 hours post-trauma. DISCUSSION: Taken together, the data revealed significant nerve cell injury without apparent cell death in this model.     

大鼠弥漫性轴突损伤后神经丝68蛋白水平减少

目的：通过检测大鼠弥漫性轴突损伤（DAI）后神经丝蛋白68（NF68）水平，探讨弥漫性轴突损伤的病理机制。方法：用一种对大鼠头颅旋转装置致伤引发大鼠DAI。Sprague-Dawley（SD）大鼠18只随机分成3组（30min,24,72h组），每组6只，在不同时间点取脑白质、海马、胼胝体和脑干标本进行NF68印记杂交（Western blot)，检查神经丝蛋白68 水平。结果：Western blot看到对照动物NF68水平没有变化，而损伤动物明显NF68的丢失，特别是脑干。NF68是蛋白质水平减少在损伤后30min即出现直到损伤后72h。在NF68丢失的同时伴有31、42．7和52Kda低分子量蛋白条带的出现，在24h最明显。结论：NF68降解是由病理性钙蛋白酶激活引起的。损伤后24h内是最佳治疗时机。     

Graded model of diffuse axonal injury for studying head injury‐induced cognitive dysfunction in rats

Diffuse axonal injury (DAI) plays a major role in the development of cognitive dysfunction, emotional difficulties and behavioral disturbances in patients following closed head injury, even when they have no definite abnormalities on conventional MRI. This study aimed to develop a highly controlled and reproducible model for DAI that simulates post‐traumatic cognitive dysfunction in humans. Sprague‐Dawley (SD) rats were subjected to impact acceleration head injury, using a pneumatic impact targeted to a steel disc centered onto their skull. The severity of injury was graded as three levels by adjusting the driving pressure at 60, 70 or 80 pounds per square inch. In vivo MRI was obtained 2 days post‐injury. Cognitive function was evaluated using the Morris water maze at 1 and 2 weeks post‐injury. HE staining and immunohistochemistry were performed to assess neuronal and axonal damages after 2 weeks. MRI demonstrated that this model induced no gross structural modification in the brain. The degree and duration of cognitive dysfunction were dependent on the force of impact. Histological analysis revealed the force‐dependent damage of the neurons and microtubule‐associated protein 2‐positive axons in the neocortex. Hippocampal damage was much less pronounced and was not linked to cognitive dysfunction. This is the first report that precisely evaluates the threshold of impact energy to lead to neocortical damage and cognitive dysfunction in rodents. This model would be suitable for clarifying the complex mechanisms of post‐traumatic brain damage and testing novel therapeutic approaches against post‐traumatic cognitive dysfunction due to diffuse axonal damage.     

弥漫性轴突损伤早期超微结构改变

目的通过观察弥漫性轴突损伤(DAI)患者伤后早期轴突的超微结构变化以探索DAI的发生机理.方法对12例DAI患者的14份活体脑组织标本进行透射电镜检查.结果 DAI患者在伤后早期可发生多方面的轴突改变,包括(1)轴突的细胞骨架破坏;(2)轴膜改变;(3)膜性细胞器的变化;(4)髓鞘的改变;(5)轴突出现肿胀和离断,轴突近侧断端呈现球状.结论在DAI的发生中,可能有多种机理参与.推测,在受到足够强的外力作用时,一些管径较细的轴突可能会立即断裂;其它受损轴突则会出现进行性的延迟性轴突断裂.在此演化过程中,细胞骨架破坏和轴膜受损继而通透性改变可能是造成轴突局灶性轴浆转运障碍最终离断的最重要的因素.     

纳络酮早期干预对大鼠弥漫性轴索损伤的影响

目的观察纳络酮早期干预对大鼠实验性弥漫性轴索损伤(DAI)的治疗效果。方法采用改良Marmarou的方法制作大鼠颅脑DAI模型。将Wister雄性大鼠99只随机分为对照(假损伤)组、损伤组和干预组,干预组用纳络酮2mg/kg于伤后45min腹腔一次性注射给药,于伤后2、6、24、72h观察动物行为、脑组织含水量及组织病理学变化。结果损伤组大鼠伤后2、6、24、72h,行为学评分(满分为21.00±0.00分)分别为(9.05±1.52)、(12.12±1.41)、(17.23±1.34)和(19.36±0.92)分;干预组各时间点分别为(9.32±1.23)、(14.48±1.54)、(18.68±1.09)和(20.18±0.75)分;其中干预组伤后6和24h与损伤组比较差异显著(P0.05)。对照组24h脑组织含水量测定结果为(78.19±0.35)%;伤后2、6、24、72h脑组织含水量,损伤组分别为(79.91±0.18)%、(80.70±0.49)%、(81.69±0.40)%和(80.32±0.42)%;干预组分别为(79.22±0.33)%、(79.59±0.46)%、(80.44±0.49)%和(79.50±0.44)%。同损伤组比较,干预组致伤6h后脑含水量均明显减轻(P0.01)。干预组光镜下病理损害明显减轻。结论纳络酮伤后早期干预,有助于减轻大鼠DAI后继发性脑损害。     

弥漫性轴索损伤后脑组织中c-fos与HSP70的表达

目的：鼠脑弥漫性轴索损伤（DAI）后c-foa mRNA和HSP70 mRNA的表达。方法：应用原位杂交技术探讨了鼠脑弥漫性轴索损伤后c-fos mRNA和HSP70mRNA的表达。结果：打击后10后钟时,皮层中即出现c-fos mRNA表达,2小时表达强度增加,6小时达高峰,24小时开始下降。海马、丘脑及脑干部位的c-fos mRNA表达方式与皮层相拟。打击后6小时,皮层与海马中开始出现HSP70mRNA的表达,24小时时表达强度增加,丘脑及脑干等部位未见HSP70 mRNA的表达。结论：（1）DAI后可出现脑组织中c-fos mRNA和HSP70mRNA的表达;（2）DAI后c-fos mRNA的表达早于HSP70mRNA;（3）c-fos mRNA于脑组织中的表达较为弥散,而HSP70mRNA的表达则局限于皮层和海马区;（4）c-fos mRNA和HSP70 mRNA在DAI后的表达,对神经细胞具有保护作用。     

The expression and changes of heat shock protein 70, MDA and haemorheology in rat cortex after diffuse axonal injury with secondary insults.

In the present study the role of heat shock protein 70 (HSP70) expression, changes of malonyldialdehyde (MDA) in rat cortex and haemorheology with time after diffuse axonal injury (DAI) only and DAI with secondary insults (SI) were studied. The rat DAI and DAI with SI model were made according to our previous work and animals were divided into a control and another five injury groups with time after injury. Immunohistochemical assay was used to detect the neuronal expression of HSP70 at 0.5h, 3h, 12h, 24h, 72h after DAI or DAI with SI. In the meantime, the high (etah ) and low whole blood viscosity (etaL ), haematocrit (HCT) and RBC aggregation index (AI = etaL/etah ) were also detected and calculated. MDA in the homogenised brain tissue was assayed by thiobarbituric acid (TBA) reaction. The results showed that HSP70 positive neurons were not detected at 30 minutes, but the number of HSP70 positive neurons begin to increase obviously at 3 hours, reach a peak at 24 hours (P< 0.01), and decrease at 72 hours (P= 0.05) after brain injury. The trend of expression of HSP70 was alike for both DAI only or DAI with SI. Meanwhile, MDA, etah, etaL, HCT and AI changes showed the same tendency. Compared with DAI only group, MDA and blood viscosity indexes in DAI with SI were significantly higher at respective time points (P< 0.01). It is concluded that HSP70 expression, MDA and haemorheology indices increased after brain injury and brain injury with SI. Free radicals and haemorheological changes play an important role in the aggravation of brain damage and HSP70 expression upregulation.     

脑弥漫性轴索损伤轴索内钙超载及钙拮抗剂的治疗作用

目的探讨脑弥漫性轴索损伤(DAI)轴索内Ca2+超载及Ca2+拮抗剂的治疗作用.方法 SD大鼠14只,分损伤组、用药组(伤后立即静注尼莫通)、对照组.用自制头颅瞬间侧向旋转装置,制作大鼠DAI模型.伤后2～24小时取延髓组织,行Ca2+电镜细胞化学处理(草酸钾-焦锑酸钾法)和观察.结果 (1)损伤组神经轴索髓鞘板层断裂、间隙扩大,轴膜与髓鞘脱离,细胞器边聚,轴浆空泡形成,线粒体稀少.受损髓鞘内有大量细小钙颗粒,髓鞘损害程度与钙颗粒数量呈正相关;伤后晚期轴浆内可见粗大钙颗粒.神经元胞体及血管内皮细胞空泡化,也有钙颗粒沉着,内皮细胞管腔面出现微绒毛.(2)用药组轴索髓鞘损伤趋于局部,线粒体数量、形态、分布近于正常,髓鞘及轴浆钙颗粒罕见,神经元胞体及血管内皮细胞空泡变明显减轻.结论 DAI中轴索存在Ca2+超载,这是导致DAI发生发展的重要因素;Ca2+拮抗剂尼莫通可改善DAI.     

硫酸镁对大鼠脑弥漫性轴索损伤海马区Bcl-2和Bax蛋白表达影响的研究

目的研究脑弥漫性轴索损伤后神经细胞迟发性死亡的机制,探讨镁离子对大鼠脑弥漫性轴索损伤后神经元的保护作用。方法采用Marmarou方法制备大鼠重度脑弥漫性轴索损伤模型,分为创伤组(n=25)、生理盐水组(n=40)和硫酸镁组(n=40)。硫酸镁组伤后半小时给予25%硫酸镁(750μmol/kg),生理盐水组在相同时间给予等量的生理盐水腹腔注射,于伤后6小时、24小时、3天、5天及7天5个时相点处死。采用HE染色、免疫组织化学技术动态观察大鼠海马区的组织病理改变,Bcl-2和Bax蛋白的表达情况,以及使用硫酸镁干预后对上述表达的影响。结果①Bcl-2蛋白的表达:假手术组大鼠海马区仅见极少量Bcl-2阳性细胞,着色淡。在伤后6小时即有大量的Bcl-2阳性细胞,随时间渐增,24小时达到高峰,3～7天逐渐减少。②Bax蛋白的表达:在DAI后大鼠海马区有大量Bax阳性细胞,在伤后6小时就有所增加,24小时显著增加,3天达到高峰。Bcl-2/Bax值在损伤后随时间逐渐上升。③硫酸镁组中,海马区的Bax表达与对照组相比有所减少,而Bcl-2相应增加,Bcl-2/Bax比值也是上调的,均有统计学意义(P<0.05)。结论大鼠脑弥漫性轴索损伤后,海马区神经元存在有迟发性细胞死亡即凋亡现象。Bax与Bcl-2参与细胞凋亡过程。硫酸镁可通过抑制Bax蛋白,上调Bcl-2蛋白,减少神经细胞凋亡,对促进神经细胞修复和功能重塑有益。