神经节苷脂GM1对大鼠脑液压伤后行为和记忆的影响

目的:探讨大鼠脑液压伤后GM1与学习记忆、脑内一氧化氮、突触素和细胞凋亡的关系.方法:液压损伤法建立大鼠脑损伤模型,随机分为治疗组、损伤组和对照组.观察伤后学习记忆改变,检测一氧化氮合酶(NOS)、一氧化氮(NO)、突触素和海马、皮质及基底节区细胞凋亡指数.结果:治疗组学习记忆成绩高于损伤组,NOS、NO明显降低,治疗组海马CA1区突触素显著增多,皮质、海马和基底节的凋亡细胞数明显减少.结论:GM1能减少海马和皮质细胞凋亡,可能有利于促进脑损伤后神经行为和记忆的恢复.     

神经节苷脂GMl对大鼠脑液压伤后行为和记忆的影响

目的探讨大鼠脑液压伤后GM1与学习记忆、脑内一氧化氮、突触素和细胞凋亡的关系.方法液压损伤法建立大鼠脑损伤模型,随机分为治疗组、损伤组和对照组.观察伤后学习记忆改变,检测一氧化氮合酶(NOS)、一氧化氮(NO)、突触素和海马、皮质及基底节区细胞凋亡指数.结果治疗组学习记忆成绩高于损伤组,NOS、NO明显降低,治疗组海马CA1区突触素显著增多,皮质、海马和基底节的凋亡细胞数明显减少.结论GM1能减少海马和皮质细胞凋亡,可能有利于促进脑损伤后神经行为和记忆的恢复.     

单侧液压脑损伤对大鼠双侧海马GFAP表达和CA1区突触传递的影响

目的研究单侧液压脑损伤(FPI)对大鼠双侧海马区胶质纤维酸性蛋白(GFAP)表达和CA1区突触传递的影响。方法建立大鼠单侧液压脑损伤模型,脑标本分为对照组(包括正常对照和假手术对照)、FPI损伤同侧组和FPI损伤对侧组。免疫组化法检测海马水平切片GFAP表达,对海马CA1区锥体神经元进行细胞内记录。结果FPI大鼠双侧海马齿状回门区和CA1区GFAP表达均比对照组明显增强。FPI损伤同侧组兴奋性输入-输出关系曲线的斜率比其他两组显著增大(P<0.05);FPI损伤同侧组和对侧组双脉冲易化(PPF)比值和抑制性突触后电位(IPSP)幅值均比对照组显著减小(P<0.05);FPI损伤同侧组和对侧组双脉冲抑制(PPD)比值均比对照组显著增大(P<0.05)。结论大鼠单侧液压脑损伤对双侧海马均可产生影响,导致双侧海马CA1区兴奋性突触传递增强,抑制性突触传递减弱。     

亚低温抑制大鼠弥漫性脑损伤后细胞凋亡的研究

目的探讨大鼠不同程度弥漫性脑损伤后脑组织的凋亡变化过程及亚低温治疗对脑细胞凋亡的抑制作用.方法采用大鼠Marmarou颅脑创伤装置制作弥漫性脑损伤模型,然后将128只Wistar大鼠分为未损伤组(对照组)、重度损伤组、轻度损伤组和亚低温治疗组.通过电子显微镜、组织切片原位末端标记DNA片段(TUNEL染色)、琼脂糖凝胶电泳(DNA Ladder法)等方法,观察和比较不同程度脑损伤后,大鼠脑皮层及海马区凋亡细胞的形态、特点和数量.结果(1)损伤后24～48 h,皮层及海马区可见大量细胞皱缩、核碎裂、核不规则等细胞凋亡现象,48 h较24 h更为严重;亚低温治疗后24～48 h,电子显微镜观察皮层及海马区未见细胞皱缩、核碎裂等细胞凋亡现象.(2)TUNEL染色结果显示,随着损伤程度的加重凋亡明显加重,损伤后48 h达高峰,然后逐渐下降.轻度损伤组细胞凋亡主要限于海马CA2和CA3区;重度脑损伤组细胞凋亡涉及整个海马结构,同时还广泛累及额顶区皮质.损伤后第24、48、72 h,皮层及海马区的凋亡细胞数量较同期未治疗组明显减少.(3)重度损伤后48 h,海马和皮层区细胞琼脂糖电泳可见典型的DNA梯状带,其他时间未见梯状带.亚低温治疗组、轻度脑损伤组及未损伤组亦未见梯状带.结论轻度弥漫性脑损伤后,脑细胞凋亡多发生于海马CA2和CA3区;重度脑损伤后皮层及海马区细胞可发生广泛凋亡.细胞凋亡随着损伤程度的加重而加重,高峰位于伤后第2 d.亚低温治疗可有效地抑制大鼠弥漫性脑损伤后的细胞凋亡.     

亚低温抑制大鼠弥漫性脑损伤后细胞凋亡的研究

目的：探讨大鼠不同程度弥漫性脑损伤后脑组织的凋亡变化过程及亚低温治疗对脑细胞凋亡的抑制作用。方法：采用大鼠Marmarou颅脑创伤装置制作弥漫性脑损伤模型,然后将128只Wistar大鼠分为未损伤组（对照组）、重度损伤组、轻度损伤组和亚低温治疗组。通过电子显微镜、组织切片原位末端标记DNA片段（TUNEL染色）、琼脂糖凝胶电泳（DNA Ladder法）等方法,观察和比较不同程度脑损伤后,大鼠脑皮层及海马区凋亡细胞的形态、特点和数量。结果：（1）损伤后24-48h,皮层及海马区可见大量细胞皱缩、核碎裂、核不规则等细胞凋亡现象,48h较24h更为严重;亚低温治疗后24-48h,电子显微镜观察皮层及海马区未见细胞皱缩、核碎裂等细胞凋亡现象。（2）TUNEL染色结果显示,随着损伤程度的加重凋亡明显加重,损伤后48h达高峰,然后逐渐下降。轻度损伤组细胞凋亡主要限于海马CA2和CA3区;重度脑损伤组细胞凋亡涉及整个海马结构,同时还广泛累及额顶区皮质。损伤后第24、48、72h,皮层及海马区的凋亡细胞数量较同期未治疗组明显减少。（3）重度损伤后48h,海马和皮层区细胞琼脂糖电泳可见典型的DNA梯状带,其他时间未见梯状带。亚低温治疗组、轻度脑损伤组及未损伤组亦未见梯状带。结论：轻度弥漫性脑损伤后,脑细胞凋亡多发生于海马CA2和CA3区;重度脑损伤后皮层及海马区细胞可发生广泛凋亡。细胞调亡随着损伤程度的加重而加重,高峰位于伤后第2d。亚低温治疗可有效地抑制大鼠弥漫性脑损伤的细胞凋亡。     

外伤后癫痫大鼠脑内突触素和苔藓纤维的观察

目的 通过研究液压脑损伤后突触索和苔藓纤维在外伤后癫痫和非癫痫的大鼠脑内的不同变化,以探讨外伤后癫痫的发病机制.方法 应用液压脑损伤复制脑损伤动物模型并记录脑电图和行为学变化,3个月后应用突触素免疫组织化学、Timm染色和汁算机图像分析技术分析皮质区突触索及海马区苔鲜纤维的不同变化.结果 突触素在皮质损伤区表达癫痫组(n=11)高于非癫痫组(n=20,P<0.05),苔藓纤维出芽在癫痫组CA3区始层明显增多(P<0.05).结论 突触素的表达增强和苔藓纤维出芽与外伤后癫痫天系密切,因果关系有待进一步研究.     

亚低温对大鼠脑创伤后海马区凋亡相关蛋白表达的影响

目的观察亚低温对大鼠创伤性脑损伤(TBI)后海马CA3区细胞凋亡及相关蛋白Bcl-2、Bax及Caspase-3表达的影响,探讨亚低温脑保护的分子生物学机制.方法将大鼠随机分成假手术、单纯脑损伤和脑损伤后亚低温治疗3组,应用改良Marmarou方法制作大鼠TBI模型,分别用流式细胞仪(FCM)和免疫组化法检测各组动物脑海马CA3区细胞凋亡率和Bcl-2、Bax及Caspase-3蛋白的表达.结果与假手术组相比,大鼠TBI后海马CA3区细胞凋亡率及Caspase-3表达增高(P<0.05),Bcl-2/Bax表达比下降(P<0.05).亚低温治疗后,大鼠脑海马CA3区细胞凋亡率及Caspase-3表达较单纯脑损伤组降低(P<0.05),而Bcl-2/Bax表达比升高(P<0.05).结论亚低温对TBI的脑保护作用机制可能与干预伤后凋亡相关基因表达并减少神经细胞凋亡有关.     

褪黑素对阿茨海默病大鼠海马突触素表达的影响

目的 研究褪黑素(melatonin,MT)对阿茨海默病(Alzheimer's disease , AD)大鼠的海马突触素表达的影响.方法 大鼠随机分为4组,分别为AD组、AD-MT大剂量干预组、AD-MT小剂量干预组和假AD组.应用β-淀粉样蛋白(Aβ)注入大鼠海马CA1区,建立大鼠AD模型,AD-MT干预组随之以MT灌胃,1次/d,直至试验结束.应用电迷宫检测大鼠学习记忆情况,用免疫组化方法检测大鼠海马CA1区突触素的表达情况.结果 MT可以明显改善AD大鼠的学习记忆能力,提高大鼠海马CA1区突触素的阳性表达.结论 MT对AD大鼠有显著脑保护作用.     

钙调神经磷酸酶对阿尔茨海默病大鼠学习记忆及海马区基质金属蛋白酶-9的影响

目的探讨钙调神经磷酸酶对阿尔茨海默病大鼠学习记忆及海马区基质金属蛋白酶-9(MMP-9)的影响。方法采用Aβ_(1-42)海马注射建立AD模型,以他克莫司(FK506)干预。用Morris水迷宫检测大鼠的空间学习记忆能力,RT-PCR、免疫组化以及明胶酶谱技术检测海马区MMP-9的表达。结果与对照组相比,AD模型组大鼠学习记忆能力明显减退(P0.01),MMP-9基因转录、蛋白表达和酶活性均明显增加(P0.05)。FK506干预后,AD大鼠学习记忆能力明显改善,其海马区MMP-9基因转录减少、酶活性降低(P0.05)。结论抑制CaN激活可改善AD症状,可能与影响MMP-9的表达有关。     

葛根素对大鼠全脑缺血再灌注后学习记忆障碍保护作用及其机制的研究

目的 探讨葛根素对大鼠全脑缺血再灌注后学习记忆能力的影响及其机制。方法 采用四血管阻断法建立SD大鼠全脑缺血再灌注损伤模型，暗回避反应法测定学习记忆能力，并应用免疫组织化学法、原位末端标记法，检测大鼠全脑缺血再灌注海马CA，区的bcl-2阳性细胞数、凋亡细胞数的动态变化。结果 (1)与再灌注组相比，葛根素组大鼠潜伏期明显延长；(2)脑缺血再灌注后，海马CA1区bcl-2蛋白的表达随再灌注时间不同而变化，缺血20min后再灌注24h达高峰，葛根素组bcl2蛋白的表达于相应的时间点明显增多；(3)脑缺血再灌注后海马CA1区神经元凋亡损伤在再灌注72h损伤最重，葛根素组可减少相应时点神经细胞凋亡数。结论 葛根素对全脑缺血再灌注后大鼠学习记忆能力具有明显的改善作用，其作用机制可能与通过上调bcl-2基因表达从而抑制或延迟脑缺血再灌注后细胞凋亡有关。     

Evaluation of learning and memory dysfunction and histological findings in rats with chronic stage contusion and diffuse axonal injury

We previously reported a modified fluid percussion device capable of consistently producing experimental cortical contusion (CC) and diffuse axonal injury (DAI) in separate groups of rats by lateral and midline fluid percussion, respectively. The purpose of the present study was to compare the differences in learning acquisition and memory retention impairments between these two types of injured rats in the chronic stage using the Morris water maze technique. We also compared the histological differences between these two different types of traumatic brain injury. The results showed a statistically significant difference in learning acquisition impairment between the sham and CC rats and also between the sham and DAI rats. However, a significant difference in memory retention impairment was observed only between the sham and DAI rats. Histologically, the neuronal cell loss of CA3 pyramidal cells in the hippocampus was observed on the ipsilateral side in the CC and bilaterally in DAI. The neuronal cell loss was seen in bilateral entorhinal cortex layer II in DAI, but it was not seen in CC. From these results, we speculate that the marked cell loss in the hippocampus CA3 region in both CC and DAI rats was related to the impairment of spatial learning acquisition. The marked cell loss in entorhinal cortex layer II in DAI rats may be one of the important factors in the impairment of spatial memory retention.     

The Number of IgG-Positive Neurons in the Rat Hippocampus Increases after Dosed Traumatic Brain Injury

To evaluate the consequences of traumatic brain injury (TBI), we used a model of lateral fluid percussion brain injury in freely moving male Wistar rats. The immediate response to TBI included development of motor excitation and tonic–clonic seizures. Morphological analysis was performed 7 day after TBI. To localize IgG in the brain, rat brain slices were double stained with antibodies against IgG and NeuN (neuronal marker). To evaluate the state of microglia, we performed staining with Isolectin B4 (a microglial marker). The number of neurons was measured in sections stained using the Nissl method. The results show the IgG accumulation in neurons adjacent to cortical focus of trauma. In the hippocampus, IgG was accumulated in the neurons of the ipsilateral hippocampal CA1 and CA2 fields and the dentate gyrus, while in the contralateral hemisphere IgG was accumulated in the neurons of the CA1 field. These changes were accompanied by activation of microglia in the hippocampus, as well as by a decrease in neuronal density in the dentate gyrus of the ipsilateral hippocampus. The results show that TBI leads to bilateral damage to the hippocampus.     

脑创伤后bcl—2蛋白的神经保护作用

目的 探讨液压脑损伤后凋亡抑制基因bcl—2的变化规律及bcl—2基因在创伤性脑损伤后细胞凋亡中的作用。方法 应用免疫组化观察大鼠中型液压脑损伤伤前及伤后6h、12h、1d、3d、7dbcl—2蛋白表达情况,应用TUNEIL和电镜观察伤后细胞死亡的形态。结果 免疫反应阳性细胞主要位于伤侧大脑半球皮质、皮层下白质、海马CAl、CA3及齿状回的神经元和神经胶质细胞,以海马CA3区最为显。在高倍镜下,表达Bcl—2蛋白的神经细胞胞核形态正常,很少见到凋亡或坏死的形态特征。伤后早期(6h),打击侧海马CA3区Bcl—2蛋白表达显下降;Bcl—2早期改变出现在伤后6h,比细胞凋亡提前表现;伤后l—3h,Bcl—2的表达下降相对缓慢。结论 bcl—2蛋白在抑制脑创伤后细胞凋亡中起重要作用,bcl—2可能是一种可诱导的神经保护因子。     

Serum extravasation and cytoskeletal alterations following traumatic brain injury in rats

Disruption of the blood-brain barrier (BBB) and neuronal cytoskeletal damage were evaluated in two commonly used rat models of traumatic brain injury. Adult rats received a lateral cortical impact (CI) or lateral fluid percussion (FP) injury of mild or moderate severity or a sham procedure. Six hours after trauma, the brains were removed and analyzed with immunocytochemical techniques for alterations in the serum protein, IgG, and the cytoskeletal protein, microtubule-associated protein 2 (MAP2). Both models induced profound alterations in these proteins in the ipsilateral cortex and hippocampus compared to sham-injured controls. Following an injury of moderate severity, the CI injury resulted in greater IgG extravasation in the cortex and hippocampus than the FP injury. Conversely, after a mild injury, IgG extravasation in the hippocampus was greater for FP than CI. All of the animals in the CI group and most of the FP group showed a loss of MAP2 in the hippocampus. The specific subregions within the cortex and hippocampus that were affected by the injury varied between models, despite having identical impact sites. These data demonstrate that there are both similarities and differences between a CI and FP injury on vascular and neuronal cystoskeletal integrity, which should be considered when utilizing these animal models to study selected features of human head injury.     

大鼠轻型颅脑损伤后星形胶质细胞与神经元的病理改变

目的 探讨轻型颅脑损伤（TBI）后神经元及星形胶质细胞改变的病理生理过程。方法 将24只成年SD大鼠随机分为轻型TBI组（n=18）和假手术组（n=6）,轻型TBI组又分为伤后3 h（n=6）、伤后24 h（n=6）、伤后72 h（n=6）三亚组。采用液压冲击法制作轻型TBI模型。采用胶质纤维酸性蛋白（GFAP）染色检测星形胶质细胞,采用Fluoro-Jade B（FJ-B）荧光染色检测变性神经元。结果 与假手术组相比,轻型TBI后3 h、24 h、72 h邻近顶叶皮质、海马CA2/3区GFAP阳性细胞数量均明显减少（P<0.05）;缺失区周围星形胶质细胞肿胀增生明显。FJ-B阳性神经元在损伤后3 h无明显增加（P>0.05）,伤后24 h皮层区FJ-B阳性神经元显著增加（P<0.05）,伤后72 h海马区FJ-B阳性神经元显著增加（P<0.05）。伤后72 h伤侧皮层区与海马区GFAP阳性细胞数和FJ-B阳性细胞数呈显著负相关（r=-0.8285,P<0.05）。结论 轻型TBI后星形胶质细胞超急性期（3 h）即出现损害和胶质反应,神经元则在急性期（24 h）至亚急性期（72 h）出现明显损害,星形胶质细胞缺失程度可以反应神经元损伤程度。     

Effects of Exercise Following Lateral Fluid Percussion Brain Injury in Rats

Previous studies have suggested that brain-derived neurotrophic factor (BDNF) is involved in memory and learning, and may be neuroprotective following various brain insults. Exercise has been found to increase BDNF mRNA levels in various brain regions, including specific subpopulations of hippocampal neurons. In the present study, we were interested in whether following traumatic brain injury, exercise could increase BDNF mRNA expression, attenuate neuropathology, and improve cognitive and neuromoter performance. We subjected adult male Sprague-Dawley rats to a fluid percussion brain injury, followed by either 18 days of treadmill exercise or handling. Spatial memory was evaluated in a Morris Water Maze (MWM) and motor function was evaluated with a battery of neuromotor tests. Neuropathology was evaluated by measuring the cortical lesion volume and the extent of neuronal loss in the hipocampus. Expression of BDNF mRNA in the hippocampus was assessed with in situ hybridization and densitometry. Hybridization signal for BDNF mRNA was significantly increased bilaterally in the exercise group in hippocampal regions CA1 and CA3 (p<0.05), but not in the granule cell layer of the dentate gyrus. No significant differences were observed between the groups in neuropathology, spatial memory, or motor performance. This study suggests that after traumatic brain injury, exercise elevates BDNF mRNA in specific regions of the hippocampus.     

Correlation of brain-derived neurotrophic factor to cognitive impairment following traumatic brain injury in rats

BACKGROUND: In vitro and in vivo studies have confirmed that brain-derived neurotrophic factor (BDNF) can promote survival and differentiation of cholinergic, dopaminergic and motor neurons, and axonal regeneration. BDNF has neuroprotective effects on the nervous system. OBJECTIVE: To explore changes in BDNF expression and cognitive function in rats after brain injury DESIGN, TIME AND SETTING: The neuropathology experiment was performed at the Second Research Room, Department of Neurosurgery, Fujian Medical University (China) from July 2007 to July 2008. MATERIALS: A total of 72 healthy, male, Sprague Dawley, rats were selected for this study. METHODS: Rat models of mild and moderate traumatic brain injury were created by percussion, according to Feeney's method (n = 24, each group). A bone window was made in rats from the sham operation group (n = 24), but no attack was conducted. MAIN OUTCOME MEASURES: At days 1,2, 4 and 7 following injury, BDNF expression in the rat frontal lobe cortex, hippocampus and basal forebrain was examined by immunohistochemistry (streptavidin-biotin-peroxidase complex method). Changes in rat cognitive function were assessed by the walking test, balance-beam test and memory function detection. RESULTS: Cognitive impairment was aggravated at day 2, and recovered to normal at days 3 and 7 in rats from the mild and moderate traumatic brain injury groups. BDNF expression in the rat frontal lobe cortex, hippocampus and basal forebrain was increased at 1 day, decreased at day 2, and then gradually increased in the mild and moderate traumatic brain injury groups. BDNF expression was greater in rats from the moderate traumatic brain injury group than in the sham operation and mild traumatic brain injury groups (P < 0.05). CONCLUSION: BDNF expression in the rat frontal lobe cortex, hippocampus and basal forebrain is correlated to cognitive impairment after traumatic brain injury. BDNF has a protective effect on cognitive function in rats following injury     

Regional expression of Par-4 mRNA and protein after fluid percussion brain injury in the rat.

Regional levels of prostate apoptosis response-4 (Par-4) protein and mRNA were measured after lateral fluid percussion (FP) brain injury in rats. Immunochemical studies indicated that Par-4 immunoreactivity (ir) is present in cortical neurons and hippocampal CA1-CA3 pyramidal neurons in uninjured rats. Increases of Par-4-ir were observed in the CA3 neurons of the ipsilateral hippocampus (IH), but not in injured left cortex (IC) at 48 h after FP brain injury. Levels of the Par-4 mRNA measured by RT-PCR assay and protein measured by Western blot procedure were significantly increased in the injured IC and IH, but not in the contralateral right cortex and hippocampus after brain injury. Levels of both Par-4 protein and mRNA were significantly increased in the IC and IH as early as 2 h and stayed elevated at 24 and 48 h after injury. These data show that the induction of proapoptotic Par-4 mRNA and protein occurs only in the IC and IH that have been observed to undergo apoptosis and neuronal cell loss after lateral FP brain injury. Because increased expression of Par-4 has been observed to contribute to apoptosis and cell death in cultured neurons, the present temporal pattern of Par-4 expression is consistent with a role for Par-4 in apoptosis and neuronal cell death after traumatic brain injury.     

Impaired expression of long-term potentiation in hippocampal slices 4 and 48 h following mild fluid-percussion brain injury in vivo

The effect of fluid percussion brain injury on hippocampal long-term potentiation (LTP) was investigated in hippocampal slices in vitro. Mild to moderate (1.7–2.1 atm) lateral fluid percussion head injury or sham operation was produced in rats 4 or 48 h prior to harvesting brain slices from the ipsilateral hippocampus. Field excitatory post-synaptic potentials (fEPSPs) were recorded in stratum radiatum of hippocampal subfield CA1 in response to electrical stimulation of the Schaffer collaterals. The initial slope of fEPSPs was used to investigate changes in synaptic strength prior to and following 100 or 200 Hz (1 s) tetanic stimulation. TBI significantly inhibited expression of LTP in hippocampal slices in vitro. Post-tetanus fEPSP slopes increased more than 100% in hippocampal slices from sham-operated animals but less than 50% in slices from rats following TBI. The data suggest that changes in functional synaptic plasticity in the hippocampus may contribute to cognitive disorders associated with TBI (traumatic brain injury). The data also indicate that TBI-induced effects on hippocampal LTP are robust and may be investigated in the hippocampal slice preparation in vitro.