大鼠脑缺血区皮层的Smac／Diablo变化

目的观察大鼠缺血区皮层Smac／Diablo的动态变化，并探讨其在缺血后神经元凋亡过程中的可能作用。方法采用RT-PCR，Westernblot方法分别测定大鼠脑缺血后不同时间点在缺血区皮层Smac／DiablomRNA和蛋白水平的表达水平。结果Smac／Diablo基因转录水平和蛋白表达的改变呈时间依赖性；RT-PCR显示模型组大鼠在脑缺血3h就有明显的Smac／DiablomRNA表达上调，6h达高峰，持续至24h后逐渐下降，48h时恢复至缺血前水平；western blot显示在脑缺血后3h有Smac／Diablo蛋白表达的增加，6h时Smac／Diablo蛋白表达至高峰（P〈0．01），48h基本恢复到缺血前水平。结论Smac／Diablo在脑缺血损伤后的病理生理过程中具有重要作用。     

凋亡抑制蛋白XIAP在难治性癫痫大鼠脑内的表达

目的研究杏仁核电刺激点燃的难治性癫痫大鼠脑内凋亡抑制蛋白XIAP表达的情况。方法建立杏仁核电刺激点燃的难治性癫痫大鼠模型,通过药物筛选用出耐药大鼠和药物敏感大鼠,采用免疫组织化学及western blot的方法,分析比较凋亡抑制蛋白XIAP在耐药组与药物敏感组的表达。结果难治性癫痫大鼠脑内XIAP的表达明显高于药物敏感组。结论癫痫大鼠脑内凋亡抑制蛋白XIAP可能参与了难治性癫痫的耐药机制。     

绿茶多酚对戊四氮致痫大鼠海马XIAP和Caspase-3表达的影响

目的 探讨绿茶多酚(Green tea polyphenols,GTPs)对癫痫大鼠海马中XIAP、caspase-3表达的影响.方法 将雄性Wistar大鼠随机分为正常对照组(NS组)、癫痫组(PTZ组)和绿茶多酚组(GTPs组).依据Racine分级标准观察各组动物行为学表现,用HE染色观察大鼠海马神经元损伤情况,Western Blot方法测定各组大鼠海马组织中XIAP及caspase-3蛋白表达变化.结果 PTZ组:大鼠海马XIAP表达水平(0.23±0.02)较NS组(0.47±0.05)明显降低(P＜0.05);caspase-3蛋白(0.63±0.12)较NS组(0.24±0.07)明显升高(P＜0.05).与PTZ组比较,GTPs组大鼠海马XIAP表达(0.53±0.10)显著升高(P＜0.05);caspase-3表达(0.30±0.09)显著降低(P＜0.05).结论 癫痫可导致海马组织中抗凋亡蛋白XIAP表达下降,凋亡执行蛋白caspase-3表达增加;而GTPs则能够上调XIAP表达,降低caspase-3的表达,推测GTPs可能通过抗凋亡途径来发挥癫痫后的神经保护作用.     

XIAP对耐苯妥英纳和卡马西平癫痫模型大鼠电生理和行为的影响

鼠在给予XIAP反义寡核苷酸后,ADT明显高于对照组(P<0.05);ADD时程明显缩短,Racine行为分级明显下降(P<0.05).结论 下调XIAP表达可以协助AEDs改善耐药大鼠的电生理活动,降低点燃后发作分级,提示XIAP参与了难治性癫痫的耐药.     

大鼠脑缺血再灌注损伤后皮层Homerla蛋白改变及意义

目的探讨大鼠脑血再灌注损伤后皮层组织Homerla蛋白的表达改变及其意义。方法选择成年雄性SD大鼠59只,随机分为正常对照组、缺血再灌注损伤后10rain、1h、3h、6h、12h、24h、48h及72h共9组,每组6只。免疫组化染色法和Western blot法测定Homerla蛋白含量,T-PCR法测定HomerlaRNA表达。结果在实验过程中5只动物死亡,54只进入结果分析。与对照组比较缺血再灌注损伤后Homerla蛋白和mRNA灰度值表达出现3个峰值,分别在10min、6h和24h,但在72h仍维持较高水平;与对照组Homerla蛋白免疫评分相比,缺血再灌注损伤后出现两个峰值,分别在6h和24h;Homerla蛋白除神经元外,在胶质细胞也表达。结论在缺血再灌注损伤后,Homerla出现3个表达高峰,可能在不同的机制的影响下对脑损伤发生发展起重要作用。     

槲皮素对大鼠癫痫持续状态后海马XIAP mRNA与蛋白表达的影响

目的研究大鼠癫痫持续状态(SE)后海马组织XIAP的表达变化及槲皮素对其表达的影响。方法建立氯化锂-匹罗卡品致痫大鼠SE模型,应用免疫组化和RT-PCR方法检测XIAP与caspase-3蛋白以及XIAP mRNA的表达。结果海马CA3区XIAP蛋白在SE后2 h(0.5503±0.0172)起逐渐增加,8 h(0.6221±0.0238)达高峰,与对照组比较(0.1507±0.0165),差异有统计学意义(P<0.01)。海马CA3区caspase-3活性蛋白在对照组未见明显表达,在SE后4~72 h明显增多。与对照组比较,SE组海马XIAP mRNA表达水平在2~8 h增加(P<0.01)。与SE组比较,槲皮素组海马XIAP mRNA表达水平及CA3区XIAP蛋白表达在8 h、24 h高于SE组(P<0.01),CA3区caspase-3活性蛋白表达在8 h、24 h、72 h低于SE组(P<0.01)。结论XIAP可能参与了SE后神经元凋亡的调控过程,槲皮素可以提高SE后海马神经元XIAP的表达。     

缺血缺氧性新生大鼠皮层神经元胞浆Smac/Diablo、caspase-9的表达及参附注射液的干预作用

目的 了解缺血缺氧性脑损伤(HIBD)新生大鼠神经元胞浆Smac/Diablo、caspase-9的变化及其相互关系,同时观察参附注射液的干预效果.方法 HIBD模型制作参照Rice等方法.新生7dSD大鼠按照完全随机数字表法分为假手术组、生理盐水对照组与参附治疗组,再按照造模后不同观察时间点又分为3 h、6 h、12 h、24 h、3 d、7 d6个亚组,每亚组8只.参附治疗组于造模后即刻腹腔注射参附注射液10 mL/kg,1次/d,连续用药3 d.生理盐水对照组用生理盐水替代参附注射液,用法用量相同;假手术组仅切开颈正中皮肤和分离右侧颈总动脉,不结扎,不缺氧.Western blotting检测各时间点各组大鼠神经元胞浆中Smac/Diablo、活化caspase-9蛋白的表达.结果 假手术组Smac/Diablo、caspase-9蛋白表达微弱.生理盐水对照组与参附治疗组2种蛋白造模后3 h即明显增加,与假手术组比较,差异有统计学意义(P＜0.05);24 h时2种蛋白表达达到峰值,3 d后明显下降,7 d时接近假手术组.其中参附治疗组Smac/Diablo蛋白表达量12 h、24 h、3 d、7 d时较生理盐水对照组明显下降,差异有统计学意义(P＜0.05);参附治疗组caspase-9蛋白12 h、24 h、3 d时较生理盐水对照组明显下降,差异有统计学意义(P＜0.05).结论 (1)HIBD新生大鼠脑皮层神经元存在Smac/Diablo蛋白胞浆转位,同时伴有胞浆活化caspase-9表达增加:参附可减少HIBD大鼠Smac/Diablo蛋白的胞浆转位,减少caspase-9的活化.(2)Smac/Diablo、caspase-9参与了HIBD新生大鼠迟发性神经元损伤的病理机制.

Abstract：

Objective To investigate the expressions of Smac/Diablo and caspase-9 and their corelations in the cytoplasm of cerebral cortex of neonatal rats with hypoxic-ischemic brain damage (HIBD), and the possible interference effects of Shenfu injection on them. Methods Postnatal 7-d SD rats were randomly divided into Shenfu treatment group (group SF), normal saline group (group C) and sham-operated group (group S). Rat models of HIBD were established according to Rice's method.Based on the observing times after the success of model making, each group (n=48) was equally divided into 6 subgroups (3, 6, 12 and 24 h, and 3 and 7 d observing groups). Rats in the group S were not performed ligation of the right common carotid artery and not underwent hypoxia but only performed the separation of right common carotid artery. Shenfu injection was administered by intraperitioneal injection right after H/I insult and then once daily at a dosage of 10 mL/kg for 3 d into the rats of group SF. Saline was also administered into the rats of group C by the same methods and at the same dosage. Cytoplasm proteins were extracted from the cerebral cortex tissue, and then, Western blotting was employed to detect the protein levels of Smac/Diablo and activated caspase-9 in cytoplasm. Results Western blotting showed that the expression levels of Smac/Diablo and activated caspase-9 in cytoplasm of group S were very low; the expression levels of Smac/Diablo and activated caspase-9 in cytoplasm of group SF and group C were increased markedly since the 3rd h of the success of model making as compared with those in group S (P＜0.05): these in the 2 groups reached their peak levels 24 h after H/I insult, gradually decreased 3 d after H/I insult, and almost returned to the original levels 7 d after H/I insult. The expressions of Smac/Diablo in cytoplasm of group SF 12, 24 h and 3 d after H/I insult was significantly lower than that of group C (P＜0.05); the expression of activated caspase-9 in cytoplasm of group SF 12,24 h and 3 d after H/I insult was significantly decreased as compared with that of group C (P＜0.05).Conclusion Smac/Diablo cytoplasm translocation and increased expression level of caspase-9 appear in the cytoplasm of cerebral cortex cells after H/I injury; Shenfu injection can inhibit the expressions of Smac/Diablo and caspase-9; Smac/Diablo and caspase-9 involve in the pathophysiological mechanisms of neuronal damage after H/I.     

大鼠局灶性脑缺血再灌流损伤时神经细胞凋亡及其调控基因的表达

目的　探讨脑缺血再灌流损伤时神经细胞凋亡及其调控基因 bcl- 2的作用。方法　采用大鼠大脑中动脉 (MCA)阻断模型阻断血流 2小时后再灌注 ,分别在不同再灌注时间将大鼠断头取脑 ,连续切片分别作 HE、TUNEL染色及 bcl- 2蛋白免疫组化染色。结果　 (1) MCA阻断后脑缺血周边区部分神经细胞发生凋亡 ,随着再灌注时间的延长 ,一定时程内凋亡细胞逐渐增多 ,2 4小时达高峰 ,各组之间及与假手术组之间差异显著 (P<0 .0 1)。 (2 )凋亡抑制基因 bcl- 2在再灌注早期 (6小时 )即达高峰 ,各组大鼠 bcl- 2表达亦存在显著差异 (P<0 .0 1)。 (3)神经细胞凋亡的出现与 bcl- 2表达在一定时程内呈直线负相关 (r=- 0 .747,P<0 .0 1)。结论　脑缺血再灌流损伤时 ,神经细胞凋亡起着重要作用 ,这种作用与 bcl- 2的表达等密切相关。     

脑缺血缺氧后X-连锁凋亡抑制蛋白的表达及黄体酮的干预研究

目的观察脑梗死大鼠脑缺血半暗带脑组织内X-连锁凋亡抑制蛋白的表达情况,并观察黄体酮治疗对其表达水平及神经细胞凋亡的影响,以进一步探讨黄体酮神经保护作用的机制。方法选择成年雄性S-D大鼠102只,质量为260~310 g,随机分为假手术组、模型组、溶剂治疗组、黄体酮治疗组。分别于脑梗死12 h、24 h、48 h 3个时间点处死大鼠,取出脑组织,应用免疫组化染色、Western blot技术检测各组大鼠缺血半暗带内X-连锁凋亡抑制蛋白的表达情况;应用原位末端标记法检测脑组织细胞的凋亡情况。采用单因素方差分析对上述结果进行统计学分析,取α=0.05为检验水准。结果脑梗死发生后,缺血半暗带内X-连锁凋亡抑制蛋白的表达水平较假手术组有所增高,经黄体酮治疗后,其表达水平明显升高,与模型组、溶剂治疗组比较,差异有统计学意义(P<0.05),黄体酮治疗组凋亡细胞数明显减少,与模型组、溶剂治疗组比较,差异亦有统计学意义(P<0.05)。结论黄体酮可减少脑梗死大鼠缺血半暗带内的脑细胞凋亡,提高脑组织中X-连锁凋亡抑制蛋白表达可能是其发挥保护作用的分子机制之一。     

大鼠脑缺血再灌注后Bcl-2、Fas蛋白的表达及意义

目的　探讨 Ｂｃｌ２ 及 Ｆａｓ 蛋白在大鼠脑缺血再灌注损伤中的表达及与缺血性凋亡的关系。方法　采用免疫组化方法观察 Ｂｃｌ２ 及 Ｆａｓ 蛋白在脑缺血再灌注后随时间延长动态变化并用图像分析测定二者的免疫强度。结果　脑缺血再灌注后 Ｂｃｌ２、 Ｆａｓ 表达。 Ｂｃｌ２ 蛋白表达于再灌注 ３ｈ 达高峰,再灌注 ６ｈ 其表达呈下降趋势,再灌注 ２４ｈ 仅少数细胞阳性表达。 Ｆａｓ 蛋白表达于再灌注 ６ｈ 达高峰,对缺血较敏感的海马大锥体细胞亦有表达,再灌注 ２４ｈ 其表达减少。结论　 Ｆａｓ 蛋白表达介导了脑缺血后细胞凋亡的发生,并可能参与了迟发性神经元死亡。 Ｂｃｌ２ 表达与神经元存活密切相关,在神经元缺血敏感性方面起重要作用,对神经元起保护作用。     

脑缺血再灌注后XIAP与Smac表达的实验研究

目的探讨XIAP与Smac在大鼠脑缺血再灌注损伤过程中表达水平的动态变化。方法采用Wis-tar雄性大鼠制作局灶性脑缺血再灌注模型,应用免疫组织化学方法检测脑内XIAP与Smac蛋白表达,应用尼氏染色及HE染色观察神经细胞死亡情况。结果局灶性脑缺血后半暗带区神经元内XIAP蛋白表达在再灌注后6h增高,12h表达最多,在48h趋于正常;再灌注6h胞浆中Smac免疫阳性细胞增多,24h表达最多,并且胞浆和胞核都着色,72h降至正常。结论脑缺血再灌注损伤能诱导XIAP与Smac基因表达,XIAP水平的早期增高是机体对脑损伤所作出的一种保护性反应;而Smac表达增高可能参与了神经细胞凋亡。     

IRAK-4在大鼠缺血性脑损伤早期的表达及意义

目的 探讨白细胞介素-1受体相关激酶-4(interleukin-1 receptor-associated kinases,IRAK-4)在大鼠大脑缺血性损伤早期的表达及意义.方法 应用大脑中动脉线栓法(MCAO)建立大鼠局灶永久性脑梗死模型,随机分为正常对照组、假手术组、缺血组、干预组.采用RT-PCR、Western blot、免疫荧光、神经功能5分评定及TTC染色等方法,检测大鼠额顶叶皮层组织IRAK-4在脑缺血性损伤早期的mRNA及蛋白表达变化、神经功能缺损程度及脑梗死体积变化,并统计各组死亡率.结果 大鼠大脑缺血性损伤早期额顶叶皮层组织IRAK-4 mRNA表达:3 h开始增加,12 h达到高峰,24 h仍维持在较高水平;IRAK-4蛋白表达:3 h开始增加,6 h达到高峰,12 h仍维持在较高水平,24 h下降与正常对照组无统计学意义;IRAK-4抑制能明显缩小脑梗死体积、改善神经功能、降低死亡率.结论 大鼠额顶叶皮层组织IRAK-4在脑缺血性损伤早期表达迅速上调,可能参与了脑缺血后炎性反应的调控,早期抑制其功能可以发挥显著脑保护作用.

Abstract：

Objective To investigate the expression and significance of Interleukin - 1 ReceptorAssociated Kinases 4( IRAK -4) in rat ischemic brain injury. Method Models of focal cerebral infarct were established by occlusion of middle cerebral artery ( MCAO ). Rats were randomly divided into normal control group, sham surgery group, ischemic group, treated group. The mRNA and protein expressions of IRAK-4 in cerebral cortex were detected by RT- PCR method, Western blot analysis and laser scanning confocal microscope(LSCM). The neurological deficits were evaluated in 0 ～ 4 scales. The infarct size was measured by TTC staining. The mortality of each group was also calculated. Results The mRNA and protein expressions of IRAK -4 in cerebral cortex increased after ischemic injury 3 hours and decreased gradually after reaching the highest level at 12 h or 6 h( P ＜0.01 ) ,after 24 h the concentration of protein showed no significant differences compared with normal control group ( P ＞ 0.05 ), but mRNA is still at a high level ( P ＜ 0.05 ) ;the inhibition of IRAK -4 could induce the cerebral infarct, neurological deficits and mortality rate. Conclusions Brain ischemic injury increased the expression of IRAK - 4 in cerebral cortex,and inhibition of neuronal IRAK-4 by IRAK- 1/4 inhibitor at the early stage could effectively protect the neuron against death. The mechanism may be related with down - regulation of the inflammation response resulted from stroke.     

Increased expression of AGS3 in rat brain cortex after traumatic brain injury

Receptor‐independent activators of G protein signaling (AGS) offer alternative modes of signal processing for the G protein signaling system that has broad mechanistic and functional significance. Previous studies have demonstrated that AGS3, which belongs to the AGS family, is involved in a number of different cellular activities. However, the distribution and function of AGS3 in the central nervous system (CNS) remain unclear. To investigate whether AGS3 is involved in CNS injury and repair, we used an acute traumatic brain injury (TBI) model in adult rats. Western blot analysis and immunohistochemistry showed a significant upregulation of AGS3 in ipsilateral peritrauma cortex. Double immunofluorescence staining showed that AGS3 was coexpressed with NeuN but rarely with glial fibrillary acidic protein. In addition, we detected that active caspase‐3 had colocalization with NeuN and AGS3, suggesting that AGS3 might be involved in the neuron apoptosis after TBI. To investigate the potential function of AGS3 further, a neuronal cell line, PC12, was employed to establish a cell apoptosis model. Western blot analysis indicated that AGS3 shared a similar dynamic variation in animal experiments, and phosphorylated cyclic AMP response element‐binding protein (CREB) increased in parallel. Additionally, knocking down AGS3 with siRNA partially attenuated the protein level of phosphorylated CREB in PC12 stimulated by H₂O₂, while reinforcing active caspase‐3 expression, demonstrating a probable antiapoptotic role through CREB played by AGS3 in neuronal apoptosis. We hypothesize that AGS3 might play an important antiapoptotic role through enhancing phosphorylation of CREB. © 2013 Wiley Periodicals, Inc.     

一氧化氮和一氧化氮合酶在大鼠局灶性脑缺血中的表达特点

目的建立脑缺血SD大鼠模型,探讨一氧化氮(NO)和一氧化氮合酶(NOS)在脑缺血模型中的表达特点。方法应用线栓法制作大脑中动脉阻塞(MCAO)局灶性脑缺血模型,根据缺血不同时间分为8组,设立假手术组和正常对照组,每组各有6只大鼠。应用硝酸还原酶法测定脑组织NO的含量,流式细胞术(FCM)定量检测硝基酪氨酸(NT)表达,化学比色法测定脑组织NOS的活性,免疫组织化学方法定位检测eNOS、nNOS和iNOS表达位置,逆转录反应系统(RT-PCR)半定量分析eNOS、nNOS和iNOS的 mRNA在脑缺血区域的表达。结果神经功能缺失评分发现缺血时间越长,神经功能缺失越明显;脑组织中NO含量与缺血时间正相关;缺血1h后NT阳性细胞百分比开始明显升高(9.50%);缺血0.5h时NOS的活性开始升高,缺血3d达到高峰[0.94nmol/(g.min)];免疫组织化学提示eNOS在神经细胞和血管内皮细胞胞浆均有表达,nNOS和iNOS抗体主要在神经细胞胞浆中表达;RT-PCR半定量分析在缺血早期(0.5h~6h),随着缺血时间延长,eNOS和nNOS表达增加,iNOS未见表达或低表达;缺血中晚期(6h~5d),iNOS高表达,并与缺血时间呈正相关,eNOS和nNOS表达明显减少。结论脑缺血时间延长,NOS的活性升高,NO在体内特异性代谢产物NT量增加,神经功能缺失越明显;NOS在缺血早期以eNOS和nNOS为主,在缺血晚期以iNOS为主。     

Endogenous brain protection by granulocyte-colony stimulating factor after ischemic stroke

Several lines of evidence have demonstrated beneficial effects of the hematopoietic factor G-CSF in experimental stroke. A conclusive demonstration of this effect in G-CSF deficient mice is, however, lacking. We therefore investigated the effect of G-CSF deficiency on infarct volumes, functional recovery, mRNA and protein expression of the matrix metalloproteinase 9 (MMP-9) after stroke. Furthermore we tested the efficacy of G-CSF substitution in G-CSF deficient animals to prevent the potential consequences of G-CSF deficiency. In the present study experimental stroke was induced in female non-treated wildtype (wt), G-CSF deficient mice and G-CSF substituted G-CSF deficient mice followed by assessment of infarct volumes, neurological outcome and sensorimotor function. In addition, immunohistochemistry and real-time PCR of the peri-ischemic area were performed. G-CSF deficient mice showed increased infarct volumes, whereas G-CSF substituted mice had a remarkable reduction in lesion size compared to wt mice. These findings are accompanied by an improvement in neurological and sensorimotor function. G-CSF deficiency resulted in an upregulation of MMP-9 in the direct peri-ischemic tissue. Treatment with G-CSF suppressed the upregulation of MMP-9. Taken together, G-CSF deficiency clearly resulted in enlarged infarct volumes, and worsened neurological outcome. G-CSF substitution abolished these negative effects, led to significant reduced lesion volumes, and improved neurological outcome. G-CSF mediated suppression of MMP-9 further demonstrates that endogenous G-CSF plays a significant role in brain protective mechanisms. We have shown for the first time that endogenous G-CSF is required for brain recovery mechanisms after stroke.     

Expression of nestin after traumatic brain injury in rat brain

We tested the hypothesis that traumatic brain injury upregulates expression of nestin, an embryonic cell intermediate filament protein. Brain from rats (n=24) subjected to controlled cortical impact injury and sham operated (n=3) and normal (n=3) rats were processed for dual label immunohistochemical study to identify cellular expression of nestin. Our results show that in normal noninjured animals, nestin is expressed slightly and localized only in a few endothelial and subventricular cells. In contrast, at 1–4 weeks postinjury nestin is strongly expressed in astrocytes and microglia. The expression of nestin in astrocytes and microglia after traumatic brain injury support the hypothesis that injured cerebral tissue expresses developmental proteins, and that these proteins may promote recovery after injury.     

颅脑损伤后不同剂量糖皮质激素应用对大鼠继发性脑损伤和死亡率的影响

目的 探讨颅脑损伤后早期应用不同剂量糖皮质激素对大鼠继发性脑损伤和死亡率的影响. 方法 将成年雄性Wistar大鼠220只按随机数字表法分为正常组、地塞米松正常给药组、甲基强的松龙正常给药组、创伤对照组、小剂量地塞米松组、中剂量地塞米松组、大剂量地塞米松组、小剂量甲基强的松龙组、中剂量甲基强的松龙组和大剂量甲基强的松龙组(后7组统称损伤组),每组各22只.损伤组通过液压打击方法制备成颅脑损伤模型且分别给予生理盐水或不同剂量不同类型糖皮质激素处理,并于伤后24 h进行改良神经功能缺损评分.采用TUNEL法于伤后24h、48h、7d和14d时检测各组大鼠损伤侧海马组织的细胞凋亡情况.观察伤后14d内各组大鼠的死亡率,并通过尸检和常规HE染色观察死亡大鼠脑组织、垂体、心脏和肺脏的变化. 结果 损伤组间伤后24h神经功能缺损评分比较差异无统计学意义(P＞0.05).损伤组大鼠海马组织中凋亡细胞于伤后24h开始出现,48 h达到高峰,7～14d内降至正常,其中大剂量地塞米松组和大剂量甲基强的松龙组凋亡细胞数在伤后48 h时均明显高于创伤对照组,差异均有统计学意义(P=0.000,P=0.002).大剂量地塞米松组和大剂量甲基强的松龙组的大鼠死亡率也均明显高于创伤对照组,差异均有统计学意义(P=0.012,P=0.038).尸检发现大剂量地塞米松组和大剂量甲基强的松龙组的死亡大鼠均有不同程度的间质性肺炎及垂体淤血. 结论 颅脑损伤可以导致海马神经细胞凋亡,而伤后早期应用大剂量糖皮质激素可进一步加重其凋亡,同时增加死亡率,其原因可能为间质性肺炎和垂体淤血的发生.     

Dexamethasone enhances NT-3 expression in rat hippocampus after traumatic brain injury

The cellular events in traumatic brain injury (TBI) are complicated, and the factors mediating neurotrophins to protect and repair the injured brain cells are only beginning to be identified. This study examined the effect of dexamethasone (DEX) on neurotrophin-3 (NT-3) expression following TBI. Levels of NT-3 mRNA and protein in rat hippocampus were measured using in situ hybridization and immunohistochemistry, respectively. After TBI, the NT-3 mRNA expression was down-regulated during the first 24 h. DEX reversed the post-traumatic reduction of NT-3 mRNA expression at 2, 4, 6, and 12 h in the hippocampus, and also decreased the cell death in hippocampal hilum and supraventricular cerebral cortex after 7 days. The NT-3 protein levels generally corresponded to the mRNA levels in the hippocampal region. DEX enhanced the NT-3 expression after TBI, indicating that post-traumatic neuroprotection in the hippocampus is at least partially mediated by NT-3 and thus can be modulated by DEX treatment.     

Changes in localization of synaptophysin following fluid percussion injury in the rat brain

Traumatic brain injuries damage neurons and cause progressing dysfunctions of the brain. Synaptophysin (SYP), a major integral transmembrane protein of synaptic vesicles, provides a molecular marker for the synapse and serves as a functional marker of the brain. This study examined magnitude-dependent changes of SYP in the rat brain 2 days following low, moderate or high fluid percussion injuries and investigated time-dependent changes of SYP in the rat brain with moderate fluid percussion injury 2, 15 and 30 days after trauma using immunohistochemistry and Western blotting. SYP immunoreactivity increased in the lateral cortex and in the subcortical white matter, with increasing magnitude of injury and time after trauma. Increased SYP immunoreactivity was accompanied with degeneration of neuronal cell bodies, their processes and terminals as well as glial cell proliferations. Amounts of SYP measured by Western blotting remained unchanged in brains with moderate fluid percussion within 30 days after trauma. These findings indicate that trauma accumulates SYP at injured sites of neurons without changing SYP contents and that increased SYP immunoreactivity in the cerebral cortex following traumatic injury reflects an inhibition of synaptic vesicle transportation and dysfunction of synapses, thus providing a histological substrate for brain dysfunctions.     

外源性bFGF对大鼠创伤性海马神经元坏死凋亡的治疗作用

目的探讨颅脑损伤后大鼠海马神经细胞发生变性坏死同时是否存在神经细胞凋亡现象,并试图应用外源性bFGF观察其对损伤后大鼠神经细胞病理学改变的治疗作用.方法应用Marmarou's颅脑损伤装置,造成Wistar大鼠重型颅脑损伤.以TUNEL法做原位细胞凋亡检测.以组织病理HE染色观察组织损伤程度.结果颅脑损伤后4小时,动物海马CA2-3区即出现少量凋亡细胞,伤后1、3天逐渐增多,伤后7天达峰值.外源性bFGF明显抑制颅脑损伤后神经细胞坏死、凋亡过程.结论颅脑损伤后,神经元发生变性、坏死同时,存在凋亡现象.海马结构bFGF基因表达不足可能是颅脑损伤后神经元坏死、凋亡的原因之一.因此脑损伤后,在常规治疗基础上,有必要给予外源性bFGF,减少神经细胞坏死及凋亡.