迷迭香酸抑制NLRP3炎性小体的活化对创伤性颅脑损伤大鼠脑组织损伤和海马区神经元凋亡的影响

目的探究迷迭香酸对NLRP3炎性小体活化的影响,从而进一步探究其对创伤性颅脑损伤大鼠脑组织损伤和海马神经元凋亡的影响。方法采用控制性皮层撞击损伤(CCI)模型法建立大鼠创伤性颅脑损伤模型,将小鼠随机分成5组,加药组分别腹腔注射5、10、20 mg/kg迷迭香酸,然后评估大鼠的神经功能缺陷评分;计算各组大鼠脑含水率及脑指数;苏木精-伊红染色观察各组大鼠脑组织海马区神经元病理学变化;TUNEL检测神经元凋亡情况;尼氏小体染色观察神经元损伤情况;蛋白印迹法检测各组大鼠脑前额叶脑源性神经营养因子(brain derived neurotrophic factor,BDNF)、神经生长因子(nerve growth factor,NGF)、NLRP3、凋亡相关微粒蛋白(apoptosis-associated speck-like protein containing CARD,ASC)、Caspase-3的蛋白表达水平;试剂盒检测活性氧(reactive oxygen species,ROS),超氧化物岐化酶(superoxide dismutase,SOD),乳酸脱氢酶(lactate dehydrogenase,LDH)的含量。结果与健康对照组比较,脑损伤模型组神经功能缺陷评分、脑含水率以及脑指数均显著升高(P0.05),神经元凋亡率,BDNF、NGF、NLRP3、ASC、Cleaved Caspase-3蛋白表达水平,ROS和LDH的含量均显著升高(P0.05),SOD活性显著降低(P0.05)。与脑损伤模型组比较,迷迭香酸中、高剂量组神经功能缺陷评分、脑含水率以及脑指数均显著降低(P0.05),海马区神经元病变范围及程度减轻,海马区神经元损伤程度减轻。与脑损伤模型组比较,迷迭香酸中、高剂量组神经元凋亡率,BDNF、NGF、NLRP3、ASC、Cleaved Caspase-3蛋白表达水平,ROS和LDH的含量均显著降低(P0.05);SOD含量显著升高(P0.05)。结论迷迭香酸可抑制NLRP3炎性小体的活化和海马区神经元凋亡并减轻创伤性颅脑损伤大鼠脑组织损伤。     

静脉移植人脂肪间充质干细胞治疗大鼠颅脑损伤

背景：动物实验及临床研究证实间充质干细胞对创伤性脑损伤具有一定的治疗作用。 目的：观察脂肪间充质干细胞移植治疗急性创伤性脑损伤大鼠行为学及损伤脑组织中胶质纤维酸性蛋白、神经元特异性烯醇化酶和巢蛋白的表达。 方法：以自由落体硬膜外撞击法制作SD大鼠脑损伤模型后随机分为3组：移植组于脑损伤48 h时经尾静脉注射Brdu标记的成人脂肪间充质干细胞;对照组不作处理;生理盐水组于脑损伤48 h时经尾静脉注射生理盐水。采用NSS评分法评价大鼠神经功能恢复情况;倒置显微镜观察脂肪间充质干细胞在损伤脑组织内的迁移情况;免疫组织化学法检测大鼠受损脑组织中胶质纤维酸性蛋白、神经元特异性烯醇化酶和巢蛋白表达。 结果与结论：移植组NSS评分明显低于对照组与生理盐水组(P < 0.05)。在受损伤脑组织周围可发现经Brdu标记的脂肪间充质干细胞。移植组大鼠受损脑组织中胶质纤维酸性蛋白和神经元特异性烯醇化酶阳性表达率明显低于对照组与生理盐水组(P < 0.05),且下降速度较快;巢蛋白表达明显高于对照组与生理盐水组(P < 0.05)。证实脂肪间充质干细胞通过血脑屏障进入受损大鼠脑组织后,以上调巢蛋白基因的表达来发挥保护神经元、促进神经发育与再生的功能。     

氟代柠檬酸抑制缺血后适应对树鼩脑缺血后海马HIF-1α/iNOS信号通路调控的脑损伤机制

目的:观察缺血后适应(PC)对树鼩脑缺血时海马HIF-1α/i NOS信号通路的调控作用,探讨抑制星形胶质细胞(AS)代谢加重脑损伤的机制。方法:光化学法建立血栓性脑缺血动物模型,氟代柠檬酸盐(FC)作为AS代谢抑制剂,于脑缺血后4 h闭/开缺血侧颈总动脉5 min,共3个循环以建立缺血PC模型。67只雄性树鼩随机分为对照组(n=9)、缺血4 h组(n=9)、缺血24 h组(n=9)、缺血PC 4 h组(n=9)、缺血PC 24 h组(n=9)、FC预处理4 h组(n=11)和FC预处理24 h组(n=11)。采用TTC染色观察树鼩脑梗死体积的变化,通过HE染色观察海马神经元病理学改变,用激光多普勒监测缺血区区域性脑血流(r CBF),免疫组化及Western blot检测海马i NOS表达,用分光光度计测定海马NO产量,用ELISA分析海马HIF-1α水平的变化。结果:脑梗死体积随缺血时间延长而增大,以缺血24 h为显著(P 0. 05);脑缺血后4 h和24 h皮层r CBF均下降(P 0. 05);而海马HIF-1α和i NOS表达增强,NO生成显著升高(P 0. 05)。缺血PC可增加皮层r CBF(P 0. 05),显著缩小脑梗死体积(P 0. 05),下调海马i NOS表达并减少NO的生成(P 0. 05)。而FC预处理组r CBF显著低于缺血组(P 0. 05),海马神经元损伤程度较缺血组加重,脑梗死体积随之增大(P 0. 05)。结论:缺血PC通过调控HIF-1α和i NOS表达而减轻缺血性脑损伤,抑制AS功能可削弱缺血PC介导的保护效应而加重脑损伤。     

创伤性脑损伤小鼠海马和皮层NONO表达变化

目的:探索创伤性脑损伤(TBI)后小鼠海马和皮层区不含POU结构的八聚体结合蛋白(NONO)表达变化。方法:重物打击法制作TBI小鼠模型,分为假手术组和TBI组,根据创伤后的时间TBI组又分为伤后6 h、24 h、3 d和7 d。Real time RT-PCR检测脑组织NONO mRNA表达,Western Blot和免疫组化检测脑组织NONO蛋白表达。结果:NONO在小鼠大脑皮层和海马区有较强表达,TBI后海马区NONO表达水平显著降低。结论:NONO在皮层和海马区均有表达,但是TBI后只有海马区NONO表达发生显著变化,实验结果为进一步研究NONO在TBI中的作用机制提供了基础。     

临床级人脐带间充质干细胞对创伤性脑损伤大鼠神经功能的改善作用北大核心

背景:创伤性脑损伤是世界范围内发生病率最高、最严重的神经系统疾病之一,暂无有效治疗方法,有研究表明间充质干细胞对创伤性脑损伤有一定的修复作用。目的:观察临床级人脐带间充质干细胞对创伤性脑损伤大鼠神经功能的改善作用。方法:将45只雌性SD大鼠随机分为3组,分别为假手术组(n=15)、模型组(n=15)和干细胞组(n=15),除假手术组外,其余两组采用改良的Feeney自由落体方法建立创伤性脑损伤模型,造模24 h后,模型组脑定位注射20μL生理盐水,干细胞组注射20μL临床级人脐带间充质干细胞悬液,共1×10^(6)个细胞,细胞移植后1,3,7,14,21 d采用改良神经功能缺损评分评估大鼠的神经功能运动;移植后21 d,采用RT-qPCR检测Bcl-2/Bax mRNA比值,RT-qPCR及免疫荧光法检测胶质细胞标记物GFAP和IBA1的表达,ELISA法检测血浆中肿瘤坏死因子α、白细胞介素6和白细胞介素10水平,苏木精-伊红染色观察脑组织结构。结果与结论:①与模型组相比,干细胞组改良神经功能缺损评分明显降低,大鼠的运动功能明显改善;②与模型组相比,干细胞组脑组织Bcl-2/Bax mRNA比值显著升高,胶质细胞标记物GFAP和IBA1 mRNA的表达显著降低,血浆肿瘤坏死因子α、白细胞介素6和白细胞介素10水平差异不显著;③苏木精-伊红染色观察干细胞组大鼠脑组织缺损、水肿和神经元凋亡等情况均有不同程度的改善;④结果表明,在创伤性脑损伤后移植临床级人脐带间充质干细胞可促进神经功能恢复,减少神经元细胞凋亡,抑制胶质细胞过度活化。     

灯盏花素对创伤性脑损伤模型大鼠脑组织中蛋白激酶C-γ表达的影响

背景:防止创伤性脑损伤后继发性损伤具有重要意义,也是脑保护性治疗的目标。目的:通过观察灯盏花素对创伤性脑损伤大鼠脑组织蛋白激酶C-γ蛋白表达的影响,初步探讨灯盏花素对脑组织的保护作用。方法:65只SD大鼠随机分为空白对照组(n=5)、假手术组(n=20)、模型组(n=20)及灯盏花素组(n=20)。模型组及灯盏花素组采用落体撞击制备脑损伤模型,假手术组切开头皮打开骨窗后即缝合。灯盏花素组伤后立即腹腔注射灯盏花素0.4 mg/(kg·d),模型组和假手术组分别腹腔注射0.4 mL/(kg·d)生理盐水。使用免疫组织化学方法检测大鼠脑组织蛋白激酶C-γ蛋白的表达。结果与结论:创伤性脑损伤后蛋白激酶C-γ蛋白表达明显增加(P0.05),在24 h到达高峰;灯盏花素能明显减少创伤性脑损伤后蛋白激酶C-γ蛋白表达(P0.05)。结果说明灯盏花素对创伤性脑损伤后的脑组织具有保护作用。     

富氢水抑制NLRP3炎症小体改善创伤性脑损伤小鼠炎症反应

目的 探讨富氢水对创伤性脑损伤(traumatic brain injury,TBI)小鼠炎症反应及对NLRP3炎症小体的影响.方法 30只SPF级C57BL/6小鼠随机分为假手术组(Sham)、创伤性脑损伤模型组(TBI)及富氢水治疗组(HRS),每组10只.除Sham组外,其余各组小鼠均采用Feeney氏自由落体法制备TBI模型,损伤1h后腹腔注射HRS(5mL/kg),每天1次,连续7天.分别于损伤后3天及7天进行小鼠神经功能缺损评分;损伤3天后检测脑组织含水量;ELISA检测脑组织中IL-1、IL-18、TNF-α水平;免疫荧光检测小鼠脑组织内胶质细胞标记物GFAP及NLRP3炎性小体共定位情况;Western blot检测各组小鼠脑组织中NLRP3及pro-Caspase-1蛋白的表达.结果 富氢水可以降低创伤性脑损伤小鼠神经功能评分,降低脑含水量;抑制炎症反应,显著降低脑组织中IL-1、IL-18、TNF-α含量,且小鼠损伤周围皮层处GFAP及NLRP3阳性表达降低;此外,HRS组小鼠脑组织中NLRP3及pro-Caspase-1蛋白表达显著减少(P＜0.05).结论 富氢盐水改善创伤性脑损伤小鼠脑损伤,与抑制NLRP3炎症小体有关.     

头孢曲松对脑损伤后海马谷氨酸及谷氨酸转运体-1的影响

目的:观察β-内酰胺抗生素头孢曲松对创伤性脑损伤大鼠海马谷氨酸(Glutamate,Glu)及谷氨酸转运体-1(Glutamate transporter subtype-1,GLT-1)的影响。方法:将60只健康成年SD大鼠随机分三组:假手术组(Sham组)、脑创伤模型组(TBI组)、头孢曲松组(CTX组),采用改良Feeney法制备大鼠创伤性脑损伤模型,致伤后立即腹腔注射头孢曲松(200mg/kg)。伤后6 h、12 h、24 h及48 h取材,采用干湿比重法测定脑组织含水量;高效液相色谱法检测大鼠海马兴奋性氨基酸Glu水平;免疫组织化学法及Western blot法检测大鼠海马组织GLT-1的分布及表达情况。结果:模型组大鼠较Sham组相比,脑组织含水量明显增加(P0.05),海马区Glu水平显著升高(P0.05),大鼠海马GLT-1的蛋白表达量明显下调(P0.05)。与模型组大鼠比较,头孢曲松治疗组大鼠脑水肿减轻(P0.05),大鼠海马Glu水平明显下降(P0.05),GLT-1的蛋白表达量上调(P0.05)。结论:β-内酰胺抗生素头孢曲松可以阻断兴奋性神经毒性,减轻脑水肿程度。     

脐血间充质干细胞移植修复缺氧缺血损伤新生大鼠的脑功能

背景：课题计划从神经细胞替代、促进内源性神经干细胞增殖和分化、保护神经元、促进突触重建以及减轻脑白质损伤等方面来探讨脐血间充质干细胞系统移植对新生大鼠缺氧缺血脑损伤后神经功能的修复作用及其机制。 目的：观察脐血间充质干细胞由静脉途径移植透过血脑屏障进入脑组织内,对新生大鼠缺氧缺血性脑损伤后脑功能修复的影响。 方法：7 d龄SD新生鼠分为3组：假手术组仅分离出左侧颈总动脉而不结扎;缺氧缺血脑损伤组制备缺氧缺血脑损伤模型;细胞移植组在缺氧缺血性脑损伤后第8天尾静脉移植人脐血间充质干细胞,前两组尾静脉注射等量的生理盐水。 结果与结论：免疫荧光观察显示移植后5周脐血间充质干细胞迁移到海马,Nissl染色结果显示脐血间充质干细胞移植后,左侧海马DG区锥体细胞尼氏小体明显增加,提示间充质干细胞移植后可分化为神经元。行为学测试结果显示：与假手术组相比,缺氧缺血脑损伤组在T迷宫实验中,自发改变率下降,在放射形迷宫中觅水时间延长,错误次数及重复次数明显增加(P < 0.05);脐血间充质干细胞静脉移植5周后,上述行为学指标均显著改善(P < 0.05)。提示脐血间充质干细胞静脉移植治疗明显改善和提高了缺氧缺血脑损伤大鼠远期的学习记忆和空间辨别能力。     

缺血后适应对树鼩脑缺血信号转导及转录激活因子3过磷酸化的调控作用

目的观察信号转导及转录激活因子3(STAT3)磷酸化在树鼩脑缺血后适应(PC)神经保护中的作用,并探讨其可能机制。方法将50只健康成年树鼩随机分为对照组、脑缺血4 h组、脑缺血24 h组、后适应4 h组和后适应24 h组(每组n=5),其中10只动物做HE染色(n=5)及电子显微镜观察(n=5)。本实验通过光化学反应建立树鼩血栓性脑缺血模型;于缺血后4 h夹闭患侧颈总动脉3次(每次5 min)实施缺血PC。采用TTC染色观察树鼩脑梗死面积的变化,通过HE和电子显微镜观察脑皮质和海马组织学改变及其超微结构变化,应用Western blotting检测皮层总STAT3(t-STAT3)及磷酸化STAT3(p-STAT3)蛋白表达变化。结果脑缺血后皮层血管内皮细胞肿胀,皮层及海马神经元损伤,线粒体肿胀、嵴溶解,以缺血24 h损伤最为明显,脑梗死面积达到(24.78±2.06)%。而皮层p-STAT3蛋白表达随缺血时间延长呈增高趋势,缺血4 h p-STAT3蛋白表达明显增高(0.24±0.1,P<0.01),缺血24 h p-STAT3蛋白表达则持续增高(0.32±0.1,P<0.01)。缺血PC处理后皮层血管内皮细胞水肿好转,皮层及海马神经元损伤减轻,脑梗死面积减小为(17.67±1.90)%(P<0.01)。与缺血组相比,缺血PC 4 h p-STAT3蛋白表达进一步升高(0.41±0.09,P<0.01),缺血PC 24 h p-STAT3蛋白表达增高更加显著(0.70±0.11,P<0.01)。结论树鼩脑缺血可导致STAT3磷酸化代偿性增强,缺血PC的脑保护作用可能与其促进STAT3过磷酸化有关。     

Traumatic brain injury induces adipokine gene expression in rat brain

Traumatic brain injury (TBI) induces cachexia and neuroinflammation which profoundly impact patient recovery. Adipokine genes such as leptin (ob), resistin (rstn) and fasting-induced adipose factor (fiaf) are implicated in energy metabolism and body weight control and are also associated with chronic low grade inflammation. Since central rstn and fiaf expression was increased following hypoxic/ischemic brain injury, we hypothesized that these genes would also be induced in the rat brain following TBI. Realtime RT-PCR detected a 2-2.5-fold increase in ob mRNA in the ipsilateral cortex and thalamus 12h following lateral fluid percussion (FP)-induced brain injury. Fiaf mRNA was elevated 5-7.5-fold in cortex, hippocampus and thalamus, and modest increases were also detectable in the contralateral brain. Remarkably, rstn mRNA was elevated in ipsilateral (150-fold) and in contralateral (50-fold) hippocampus. To test whether these changes were part of an inflammatory response to TBI we also examined the effects of an intracerebral injection of lipopolysaccharide (LPS). We determined that central injection of LPS produced some, but not all, of the changes seen after TBI. For example, in contrast to the stimulatory influence of TBI, LPS had no effect on ob expression in any brain region, though fiaf and rstn mRNA levels were significantly elevated in both ipsi- and contralateral cortex. In conclusion: (a) brain-derived adipokines could be involved in the acute pathology of traumatic brain injury partly through modulation of central inflammatory responses, but also via leptin-mediated neuroprotective effects and (b) TBI-induced brain adipokines may induce the metabolic changes observed following neurotrauma.     

MK-801对新生大鼠脑外伤后神经元凋亡的影响

目的：探讨N-甲基-D-天冬氨酸(NMDA)受体拮抗剂MK-801对新生大鼠创伤性脑外伤(traumatic brain injury,TBI)后神经元凋亡的影响。方法：建立新生7 d大鼠顶叶皮质挫伤模型,在TBI前30 min、TBI后即刻、TBI后30 min分别给予腹腔注射MK-8011 mg/kg,在TBI后24 h取脑,连续切片,行H-E染色和Caspase-3免疫组化染色,检测脑神经元细胞的损伤和凋亡。结果：MK-801三组不同时间用药组与TBI组相比,在创伤同侧的扣带皮质、顶叶皮质和丘脑神经元凋亡细胞数减少,有显著性差异。其中TBI后即刻用MK-801治疗效果最好。结论：MK-80l能明显减少TBI后神经元的凋亡。     

An NMR metabolomic investigation of early metabolic disturbances following traumatic brain injury in a mammalian model

The effects of traumatic brain injury (TBI) on brain chemistry and metabolism were examined in three groups of rats using high-resolution (1)H NMR metabolomics of brain tissue extracts and plasma. Brain injury in the TBI group (n = 6) was produced by lateral fluid percussion and regional changes in brain metabolites were analyzed at 1 h after injury in hippocampus, cortex and plasma and compared with changes in both a sham-surgery control group (n = 6) and an untreated control group (n = 6). Evidence was found of oxidative stress (e.g. decreases in ascorbate of 16.4% (p<0.01) and 29.7% (p<0.05) in cortex and hippocampus, respectively) in TBI rats versus the untreated control group, as well as excitotoxic damage (e.g. decreases in glutamate of 14.7% (p<0.05) and 12.3% (p<0.01) in the cortex and hippocampus, respectively), membrane disruption (e.g. decreases in the total level of phosphocholine and glycerophosphocholine of 23.0% (p<0.01) and 19.0% (p<0.01) in the cortex and hippocampus, respectively) and neuronal injury (e.g. decreases in N-acetylaspartate of 15.3% (p<0.01) and 9.7% (p>0.05) in the cortex and hippocampus, respectively). Significant changes in the overall pattern of NMR-observable metabolites using principal components analysis were also observed in TBI animals. Although TBI clearly had an effect on the metabolic profile found in brain tissue, no clear effects could be discerned in plasma samples. This was at least partly due to large variability in dominant glucose and lactate peaks in plasma. However, disruption of the blood-brain barrier and the subsequent movement of metabolites from brain into blood may have been relatively small and below the detection limits of our analytical procedures. Overall, these data indicate that TBI results in several significant changes in brain metabolism early after trauma and that a metabolomic approach based on (1)H NMR spectroscopy can provide a metabolic profile comprising several metabolite classes and allow for relative quantification of such changes within specific brain regions. The results also provide support for further development and application of metabolomic technologies for studying TBI and for the utilization of multivariate models for classifying the extent of trauma within an individual.     

大鼠创伤性脑损伤后细胞凋亡及NOS阳性细胞的变化

目的：探讨大鼠创伤性脑损伤后不同时相皮质、海马、隔区细胞凋亡及NOS、ChAT阳性细胞的变化。方法：采用大鼠自由落体脑损伤模型，伤后1、2、3、4、5、7、10d取脑切片，经Nissl染色，用TUNEL法检测细胞凋亡，NADPH—d组化染色观察NOS阳性细胞，ChAT免疫组化染色观察隔区ChAT阳性细胞。结果：Nissl染色可见损伤侧海马CA2、CA3区锥体细胞层细胞消失或紊乱。损伤区周围皮质凋亡细胞伤后3d达到高峰；损伤侧海马凋亡细胞伤后5d达到高峰；损伤侧隔区凋亡细胞7d达到高峰。正常侧上述脑区各时相点均未见到凋亡细胞。损伤区周围皮质、损伤侧海马和隔区iNOS阳性细胞数量明显增加。损伤侧隔区ChAT阳性神经元也明显减少。结论：大鼠创伤性脑损伤后损伤区周围皮质和损伤侧海马、隔区细胞凋亡数量的变化与伤后时程有关。伤后细胞iNOS表达增加是导致细胞凋亡的因素。     

Changes in macrophage inflammatory protein-1 (MIP-1) family members expression induced by traumatic brain injury in mice

A deep knowledge of the profound immunological response induced by traumatic brain injury (TBI) raises the possibility of novel therapeutic interventions. Existing studies have highlighted the important roles of C-C motif ligands in the development of neuroinflammation after brain injury; however, the participation of macrophage inflammatory protein-1 (MIP-1) family members in this phenomenon is still undefined. Therefore, the goal of our study was to evaluate changes in macrophage inflammatory protein-1 (MIP-1) family members (CCL3, CCL4, and CCL9) and their receptors (CCR1 and CCR5) in a mouse model of TBI (induced by controlled cortical impact (CCI)). We also investigated the pattern of activation of immunological cells (such as neutrophils, microglia and astroglia), which on one hand express CCR1/CCR5, and on the other hand might be a source of the tested chemokines in the injured brain. We investigated changes in mRNA (RT-qPCR) and/or protein (ELISA and Western blot) expression in brain structures (the cortex, hippocampus, thalamus, and striatum) at different time points (24 h, 4 days, 7 days, 2 weeks, and/or 5 weeks) after trauma. Our time-course studies revealed the upregulation of the mRNA expression of all members of the MIP-1 family (CCL3, CCL4, and CCL9) in all tested brain structures, mainly in the early stages after injury. A similar pattern of activation was observed at the protein level in the cortex and thalamus, where the strongest activation was observed 1 day after CCI; however, we did not observe any change in CCL3 in the thalamus. Analyses of CCR1 and CCR5 demonstrated the upregulation of the mRNA expression of both receptors in all tested cerebral structures, mainly in the early phases post injury (24 h, 4 days and 7 days). Protein analysis showed the upregulation of CCR1 and CCR5 in the thalamus 24 h after TBI, but we did not detect any change in the cortex. We also observed the upregulation of neutrophil marker (MPO) at the early time points (24 h and 7 days) in the cortex, while the profound activation of microglia (IBA-1) and astroglia (GFAP) was observed mainly on day 7. Our findings highlight for the first time that CCL3, CCL4, CCL9 and their receptors offer promising targets for influencing secondary neuronal injury and improving TBI therapy. The results suggest that the MIP-1 family is an important target for pharmacological intervention for brain injury.     

碱性成纤维细胞生长因子对小鼠创伤性脑损伤后神经元凋亡及星形胶质细胞活化的影响

目的 观察碱性成纤维细胞生长因子(bFGF)对小鼠脑损伤后伤侧皮质和海马神经元凋亡及星形胶质细胞活化的影响. 方法 36只小鼠随机分为对照组、生理盐水组、bFGF组,每组各12只.采用自由落体打击装置建立脑损伤模型,分别于建模后3d和7d取脑(每时相点6只),应用免疫荧光双标和免疫印迹法检测大脑皮质、海马神经细胞凋亡因子caspase-3的变化,以及大脑皮质中胶质纤维酸性蛋白(GFAP)的表达. 结果 bFGF组皮质和海马中caspase-3的表达比生理盐水组和对照组减少(P<0.05);bFGF组皮质中GFAP表达比生理盐水组和对照组增加(P<0.05);生理盐水组与对照组的caspase-3及GFAP表达差异无统计学意义(P>0.05). 结论 bFGF能降低小鼠脑损伤后大脑皮质和海马caspase-3表达并增高大脑皮质GFAP表达,从而促进大脑皮质星形胶质细胞活化和抑制神经细胞凋亡.     

Edaravone对大鼠弥漫性脑创伤后ERK1/2通路的影响

为探讨Edaravone对脑创伤的保护机制,本研究观察了Edaravone对弥漫性脑创伤大鼠脑组织磷酸化细胞外信号调节激酶ERK1/2表达变化的影响。114只雄性SD大鼠,随机分为3组:(1)假手术对照组(A组,n=18),(2)创伤组(B组,n=48),(3)Edaravone治疗组(C组,n=48),采用Marmarou’s法建立大鼠弥漫性颅脑损伤模型。伤后1、3、6、24、48和72h,HE染色观察伤后皮质和海马区神经细胞组织形态变化,Western blot法、免疫组化法检测皮质和海马区p-ERK1/2的表达,术后24、48、72h对大鼠神经运动功能和综合运动能力评分。结果显示:光镜下,伤后6、24h即可见B组大脑皮质和海马区神经细胞胞体收缩呈三角形,胞浆嗜色性减弱,核皱缩浓染,细胞周围出现空隙,即神经细胞变性坏死改变,C组上述改变明显减轻;免疫组化与Western blot法结果显示,与A组比较,B组ERK1/2(即p-ERK1/2)活性在伤后1、3、6、24、48h显著增高(P<0.05);与B组比较,C组中p-ERK1/2在6、24及48h显著回降(P<0.05);神经功能与综合运动能力评分在B组中(8.73±1.4,63.8±27.7)明显低于A组(24.00±0.00,278.4±27.7),C组(17.36±1.63,117.6±20.9)显著回升(P<0.05)。本研究表明Edaravone可改善脑创伤后神经功能损伤,其机制与调节脑创伤后ERK1/2信号活化水平有关。     

大鼠创伤性脑损伤后星形胶质细胞的变化

目的：探讨大鼠创伤性脑损伤后星形胶质细胞的形态学变化及GFAP和NOS的表达情况。方法：采用大鼠自由落体脑损伤模型，伤后1、3、7d取脑切片，行Nissl染色以及GFAP免疫组化和NADPH—d组化单标记及双标记染色。结果：损伤区周围皮质GFAP阳性细胞胞体增大、突起增粗增长，GFAP阳性细胞数量与正常侧及对照组相比，伤后1d即有明显增加，伤后3d、7d数量持续增加；损伤侧海马CAI～3区和DG各层GFAP阳性细胞排列紊乱，胞体增大、突起增粗增长，GFAP阳性细胞数量与正常侧及对照组相比则无明显变化。损伤区周围皮质、损伤侧海马NOS阳性细胞数量明显增加。伤后3d损伤区周围皮质和损伤侧海马中GFAP与NOS双标细胞分别占GFAP阳性细胞的14．2％和13．4％左右。结论：大鼠创伤性脑损伤后大量的星形胶质细胞活化、GFAP表达增加并且部分转化为NOS阳性细胞，提示其参与了脑组织的损伤与修复过程。     

Sources of endothelin-1 in hippocampus and cortex following traumatic brain injury

Endothelin 1 (ET-1) exerts normally a powerful vasoconstrictor role in the control of the brain microcirculation. In altered states, such as following traumatic brain injury (TBI), it may contribute to the development of ischemia and/or secondary cell injury. Because little is known of ET-1's cellular compartmentalization and its association to vulnerable neurons after TBI, we assessed its expression (both mRNA and protein) in cerebral cortex and hippocampus using correlative in situ hybridization and immunocytochemical techniques.Sprague-Dawley male rats were killed at 4, 24 or 48 h after TBI (450 g from 2 m, Marmarou's model). Semiquantitative analysis of our in situ hybridization results indicated a 2.5- and a 2.0-fold increase in ET-1 mRNA content in the hippocampus and cortex respectively which persisted up to 48 h post TBI. At 4 and 24 h after TBI enzyme-linked immunosorbent assay showed a tendency for increased ET-1 synthesis. In animals subjected to TBI, qualitative immunocytochemical analysis revealed a shift in ET-1 expression from astrocytes (in control animals) to endothelial cells, macrophages and neurons. Astrocytes and macrophages were identified unequivocally by using double immunofluorescence revealing ET-1 and glial fibrillary acidic protein or ED-1, respectively, the markers being specific for these cellular types. While this redistribution was most prominent at 4 and 24 h post TBI, at 48 h the endothelial cells remained strongly ET-1 immunopositive.The results suggest that cellular types which in the intact animal synthesize little or no ET-1 provide novel sources of the peptide after TBI. These sources may contribute to the sustained cerebrovascular hypoperfusion observed post TBI.     

Effect of glycine and glycine receptor antagonists on NMDA-induced brain injury

In postnatal day 7 rats, a unilateral intrastriatal injection of 12.5 nmol of N-methyl-D-aspartate (NMDA) reproducibly injures the ipsilateral striatum, adjacent hippocampus and overlying cortex. The severity of injury can be quantified by comparing cerebral hemisphere weights in animals sacrificed 5 days after the injection. Co-injection of NMDA and the glycine receptor antagonists kynurenic acid (KYN) or 7-chlorokynurenic acid (7-CKA) reduced the severity of NMDA-induced damage in a dose-dependent fashion. One hundred nmol of KYN with 12.5 nmol of NMDA reduced average % damage from 19.3 +/- 0.9% (n = 9) to 2.3 +/- 0.5% (n = 6), P less than 0.001, ANOVA. Co-injection of 40 nmol of 7-CKA with 12.5 nmol of NMDA (n = 6) reduced average % damage from 17.1 +/- 1.6% (n = 15) to 3.0 +/- 0.6%, P less than 0.001, ANOVA. Concurrent injection of 1000 nmol glycine with 5 nmol NMDA did not increase the extent of NMDA-induced damage. Our results demonstrate that glycine receptor antagonists attenuate NMDA-induced brain injury in vivo.