小鼠次声刺激后海马内bcl-2mRNA表达的变化

目的研究小鼠接受不同声压级次声刺激后海马内bcl-2mRNA表达的改变。方法BALB／C小鼠暴露于16Hz，声压为90dB和130dB次声。每天作用2h，分别作用1、7、14、21和28d后，采用原位杂交方法观察小鼠海马内bcl-2mRNA表达的改变。结果90dB和130dB次声作用后，海马区域内bcl-2mRNA的表达明显增多；130dB次声作用组反应比90dB次声作用组强；在相同声压级强度的次声作用下，随着作用次数的增加，海马内bcl-2mRNA的杂交阳性反应产物增多。结论海马对次声作用敏感，次声可以通过改变海马内bcl-2mRNA的含量造成脑损伤，这是次声导致脑损害的重要因素之一。次声的这一作用效应与声压级和作用时间有关。     

次声对大鼠海马5-HT、5-HTR、RyR表达及恢复的研究

目的研究大鼠海马5-羟色胺(5-HT)、5-羟色胺受体(5-HTR)、兰尼定受体(RyR)表达在8 Hz、130 dB的次声作用后1周和2周时的恢复情况. 方法大鼠暴露于8 Hz、130 dB次声1、7、14、21、28、35、42 d后置安静环境观察1周或2周,取脑组织并进行免疫组织化学染色,光学显微镜下观察海马5-HT、5-HTR、RyR表达. 结果次声作用组大鼠脑组织海马5-HT、5-HTR、RyR表达均较对照组减少,最低值分别出现于21 d、28 d和42 d(P<0.01).次声停止作用后,5-HT、5-HTR、RyR表达均逐渐回升,且随时间延长大部分恢复到正常对照水平.结论 8 Hz、 130 dB次声可引起大鼠海马5-HT、5-HTR、RyR表达减少,其变化规律与观察指标有关;次声引起的5-HT、5-HTR、RyR表达减少在停止次声作用后可逐渐恢复正常.     

16Hz次声作用对大鼠海马TRPV4、GFAP和fos蛋白表达的影响

目的研究16Hz，90dB和130dB次声作用后，大鼠海马瞬时感受电位香草酸家族4（TRPV4）通道蛋白、胶质纤维酸性蛋白（GFAP）和fos蛋白的表达情况。方法16Hz，90dB和130dB次声作用于大鼠，2h／d，作用7d后采用免疫组织化学染色方法，观察大鼠海马中TRPV4蛋白、GFAP和fos蛋白表达的情况。结果16Hz，130dB次声作用7d后，与对照组相比较大鼠海马中显著表达TRPV4阳性神经元，GFAP阳性星形胶质细胞和fos阳性神经元（P〈0．05），三者分布一致，关系密切；90dB组大鼠的上述三种蛋白表达均较130dB组弱（P〈0．05）。结论16Hz，90dB和130dB次声作用可以引起大鼠海马TRPV4阳性细胞表达增多，且能够激活神经元和星形胶质细胞。     

8Hz次声对大鼠海马和颞叶皮层RyR的表达影响

目的研究8 Hz,90 dB、100 dB、130 dB的次声对SD大鼠海马及颞叶皮层兰尼定受体(RyR)表达的影响. 方法雄性SD大鼠随机分为正常对照组、8 Hz,90 dB、100 dB、130 dB的1、7、14、21、28、35、42 d组共28组.最后一次作用结束后立即取脑组织并进行RyR免疫组织化学染色,光学显微镜下观察海马及颞叶皮层RyR表达的变化. 结果次声作用组大鼠脑组织海马及颞叶皮层RyR表达均较对照组减少, 8 Hz, 90 dB组、100 dB组以21 d减少最为明显,而130 dB组变化较为复杂,有2个峰值,14 d和42 d,其中42 d阳性表达最少(均 P <0.01),且21 d时,100 dB组的表达减少较90 dB组为少,90 dB组和100 dB组阳性表达在21 d后均有所回升. 结论 8 Hz,90 dB、100 dB和130 dB次声可引起大鼠海马及颞叶皮层RyR表达减少,其变化规律与次声作用参数有关.     

不同声压级次声作用后小鼠海马内白细胞介素-6 mRNA的变化

目的研究不同声压级次声作用小鼠后海马内白细胞介素-6(interleuk in,IL-6)mRNA的改变和意义。方法BALB/C小鼠暴露于16 Hz、声压90 dB和130 dB次声。每天作用2 h,分别作用1、7、14、21和28 d后,采用原位杂交方法观察小鼠海马内IL-6 mRNA的改变。结果发现90 dB和130 dB次声作用后IL-6 mRNA的表达在海马区域明显增多;130 dB次声作用较90 dB次声作用强;在相同强度的次声作用下,作用次数的多少与海马内IL-6 mRNA的改变程度呈正相关。结论海马区域对次声敏感,次声的作用效应与声压级和作用时间有关;次声可以通过海马内IL-6 mRNA的改变造成脑损伤,这是次声导致脑损害的重要因素之一。     

次声作用后小鼠脑SOD、GSH-Px、MDA的变化及姜黄素的治疗作用

目的观察次声作用后小鼠记忆功能及脑超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、丙二醛(MDA)的变化和姜黄素的治疗作用并初步探讨其机制.方法Morris水迷宫成绩相近的BALB/C小鼠接受16 Hz、130dB的次声作用2 h/d,同时给予不同剂量的姜黄素,14 d后再次评定水迷宫成绩,并测定脑组织中SOD、GSH-Px、MDA的变化,各组间相互比较.结果单纯次声作用后,小鼠记忆功能明显下降,脑组织中GSH-Px活性及MDA含量上升(P＜0.05),SOD活性变化不明显.各用药组与单纯次声组相比,记忆功能改善,脑组织中GSH-Px活性及MDA含量下降(P＜0.05),SOD活性变化不明显.结论16 Hz、130dB次声可导致小鼠脑组织过氧化,使记忆功能受损.姜黄素可通过抗氧化作用减轻次声引发的这些损害.     

次声对成年大鼠齿状回神经前体细胞增殖的影响

目的研究次声对成年大鼠海马齿状回神经前体细胞增殖的影响。方法大鼠随机等分为正常对照组、假次声组和次声组（每组16只）。次声组暴露于8Hz、130dB次声环境7d（2h／d），暴露结束后第1、3、7、14d处死，采用抗5-溴脱氧尿嘧啶尿苷（BrdU）免疫组化方法，观察齿状回BrdU阳性细胞数的变化。结果次声作用结束后第1d，齿状回BrdU阳性细胞数与假次声组和正常对照组相比均无统计学差异；第3d及第7d，BrdU阳性细胞数减少（P〈0．05），第14d恢复正常水平。结论8Hz、130dB次声可抑制正常成年大鼠海马神经前体细胞增殖，可能与次声引起大鼠脑内微环境改变有关。     

缺氧预处理对创伤性脑损伤大鼠 Claudin5 表达及血脑屏障通透性的影响

目的探讨缺氧预处理对创伤性脑损伤大鼠脑组织紧密连接蛋白Claudin-5的表达及血-脑屏障通透性的影响。方法204只大鼠随机分为创伤性脑损伤组（T组）96例,缺氧预处理后脑损伤组（H组）96例及对照组12例。T组行自由落体撞击法建立大鼠创伤性脑损伤模型,H组给予3d缺氧预处理后,同法致脑损伤,两组大鼠于伤后1h、4h、8h、12h、24h、3d、7d、14d断头处死。采用干湿重法测脑组织含水量：Real—timePCR和Westernblot检测各组大鼠挫伤区周围脑组织Claudin-5mRNA及蛋白表达变化;IgG法检测血一脑屏障通透性变化。结果T组和H组伤后1hClaudin-5mRNA及蛋白表达开始降低,8～12h降至最低点,1d开始上升,直至伤后14d渐趋于对照组水平;其中H组各时间点Claudin-5mRNA及蛋白表达均高于T组。T组各时间点血一脑屏障通透性及脑组织含水量均明显高于H组（P〈0．05）,且两组均高于对照组（P〈0．05）。结论缺氧预处理可在创伤性脑损伤早期上调紧密连接蛋白Claudin-5的表达,维持血-脑屏障完整性,减轻脑水肿。     

大鼠重型颅脑损伤急性期水通道蛋白4的表达

目的探讨水通道蛋白（AQP4）在大鼠重型脑外伤急性期的表达变化及其与脑水肿间的关系。方法49只成年雄性SD大鼠,随机分为对照组及实验组（伤后4h、8h、12h、24h、5d共5组）。制作重度冲击加速性损伤模型,分别于伤后4h、8h、12h、24h、72h、5d采用干湿比重法测脑组织含水量,原子吸收分光光度法测定Na^＋、K^＋含量,Evans Blue（EB）测定法观察大鼠血-脑屏障（BBB）通透性变化,半定量逆转录聚合酶链反应（RT-PCR）检测脑组织AQP4 mRNA表达及其变化。结果脑组织AQP4 mRNA在伤后4h开始表达上调,8h、12h依次增高,24h达到峰值（P〈0.05）,3d时仍维持较高水平,伤后5d有所降低。脑含水量、Na^＋含量的变化与AQP4 mRNA表达变化一致。经相关性分析,AQP4 mRNA的表达与脑含水量及脑EB含量均呈正相关（P〈0.05）。结论重型脑损伤急性期,AQP4 mRNA表达的变化与颅脑损伤后BBB的破坏及脑水肿的形成和发展密切相关。AQP4可能参与重型脑损伤后脑水肿的形成并起重要作用。     

电针预处理对大鼠脑缺血再灌注损伤后EAAT2的表达研究

目的研究电针预处理对脑缺血再灌注损伤后大鼠缺血半暗带兴奋性谷氨酸转运体2(EAAT2)表达的影响,探讨EAAT2在电针预处理诱导脑缺血耐受中的作用。方法 18只SD雄性大鼠随机分为3组(n=6):分别为假手术(Sham)组、右侧大脑中动脉阻闭(MCAO)组、电针预处理(EA)组。假手术组仅分离血管,不进行阻闭,术后24 h检测;MCAO组用MCAO法致缺血120 min后于再灌注24 h检测;EA组大鼠予电针刺激30 min,刺激结束2 h后处理同MCAO组。3组大鼠在观察神经行为学变化后取材,通过2,3,5-氯化三苯四唑(TTC)染色评估梗死面积,并检测EAAT2 mRNA及蛋白表达水平。结果电针预处理能明显降低脑梗死容积百分比(P0.01),提高MCAO大鼠神经行为学评分,诱导脑缺血耐受并抑制脑缺血再灌注损伤后24 h EAAT2表达的下降(P0.01)。结论脑缺血再灌注损伤后,EAAT2表达下降,而电针预处理能显著抑制缺血半暗带EAAT2的表达下调,诱导脑缺血耐受,从而减轻脑缺血再灌注损伤。     

次声对成年大鼠脑室下区神经前体细胞增殖的影响

目的探讨次声作用对成年大鼠脑室下区（SVZ）神经前体细胞增殖的影响。方法成年雄性Sprague-Dawley大鼠（n=24）随机分为正常对照组、对照组和次声组,次声组动物置于次声压力仓（16Hz、130dB）内连续作用7d（2h/d）。照射结束后,分别于3d、7d、10d和14d处死。处死前各组大鼠腹腔注射5-溴脱氧尿嘧啶尿苷（BrdU）3次,以BrdU免疫组织化学法检测各组SVZ内增殖细胞数目的变化。结果次声照射结束后3d,次声处理组动物SVZ区的BrdU阳性细胞数目较对照组显著减少（P〈0.01）,7d时阳性细胞数继续降低（P〈0.01）,但10d时开始逐渐恢复,14d时达到正常水平（P〉0.05）。结论16Hz、130dB次声可抑制成年大鼠SVZ神经前体细胞增殖。     

130dB次声作用后大鼠下丘脑神经细胞钙离子分布

目的观察16Hz、130dB次声连续作用后大鼠下丘脑内钙离子的分布变化规律。方法用16Hz、130dB次声连续作用1、7、14、21次，2h／次／d。分别于作用后0．5、12h观察大鼠下丘脑内钙离子的分布。结果空白组、对照组下丘脑神经细胞结构正常，钙离子呈规则的圆形黑色小颗粒，边缘整齐。主要分布于神经细胞核、线粒体、内质网、神经细胞和胶质细胞的突起中。次声组下丘脑神经细胞的超微结构都有损伤改变伴随钙离子颗粒减少。结论次声可损伤大鼠下丘脑内神经细胞，损伤程度和次声作用参数及机体代偿作用有关。     

16Hz 130dB次声预处理对大鼠局灶性脑缺血的保护作用

目的观察次声预处理对大鼠大脑中动脉阻闭（MCAO）模型致脑缺血的保护作用。方法SD雄性大鼠随机分为三组（每组10只）：对照组、假次声预处理组和次声预处理组。次声预处理组大鼠行16 Hz 130 dB的次声作用2 h/d,连续作用7 d;假次声预处理组大鼠每日放入次声仓但不接受次声,亦连续7 d;对照组大鼠正常饲养。最后一次预处理后24 h时,三组大鼠分别做MCAO模型,再灌注24 h后处死动物,观察脑梗死容积及神经功能学评分。结果与对照组相比,次声预处理组大鼠脑梗死容积明显减小（P〈0.05）,神经功能学评分明显提高（P〈0.05）。而假次声预处理组大鼠脑梗死容积和神经功能学评分与对照组相比无明显差异（P〉0.05）。结论16 Hz 130 dB次声预处理可明显减轻大鼠脑梗塞的容积,改善神经功能学评分。     

Increased expression of the neuronal glutamate transporter (EAAT3/EAAC1) in hippocampal and neocortical epilepsy

PURPOSE: To define the changes in gene and protein expression of the neuronal glutamate transporter (EAAT3/EAAC1) in a rat model of temporal lobe epilepsy as well as in human hippocampal and neocortical epilepsy. METHODS: The expression of EAAT3/EAAC1 mRNA was measured by reverse Northern blotting in single dissociated hippocampal dentate granule cells from rats with pilocarpine-induced temporal lobe epilepsy (TLE) and age-matched controls, in dentate granule cells from hippocampal surgical specimens from patients with TLE, and in dysplastic neurons microdissected from human focal cortical dysplasia specimens. Immunolabeling of rat and human hippocampi and cortical dysplasia tissue with EAAT3/EAAC1 antibodies served to corroborate the mRNA expression analysis. RESULTS: The expression of EAAT3/EAAC1 mRNA was increased by nearly threefold in dentate granule cells from rats with spontaneous seizures compared with dentate granule cells from control rats. EAAT3/EAAC1 mRNA levels also were high in human dentate granule cells from patients with TLE and were significantly elevated in dysplastic neurons in cortical dysplasia compared with non-dysplastic neurons from postmortem control tissue. No difference in expression of another glutamate transporter, EAAT2/GLT-1, was observed. Immunolabeling demonstrated that EAAT3/EAAC1 protein expression was enhanced in dentate granule cells from both rats and humans with TLE as well as in dysplastic neurons from human cortical dysplasia tissue. CONCLUSIONS: Elevations of EAAT3/EAAC1 mRNA and protein levels are present in neurons from hippocampus and neocortex in both rats and humans with epilepsy. Upregulation of EAAT3/EAAC1 in hippocampal and neocortical epilepsy may be an important modulator of extracellular glutamate concentrations and may occur as a response to recurrent seizures in these cell types.     

Focal reduction of neuronal glutamate transporters in human neocortical epilepsy

PURPOSE: To study the differential expression of excitatory amino acid transporters (EAATs) at localized epileptic foci compared to nonepileptic regions in human neocortical epilepsy. Decreased expression of EAATs, the predominant mechanism to remove synaptic-released glutamate, may explain mechanisms of heightened excitability at these epileptic foci. METHODS: The differential expression of EAAT1-4 at the mRNA and protein levels was measured in electrically mapped human neocortical tissues using quantitative real-time PCR and immunoblotting. This required a novel way to prevent aggregation of EAAT proteins through cold solubilization. Layer-specific neuronal densities were measured to control for potential differences in neuronal density. RESULTS: While focal epileptic brain regions show marked increases in immediate early genes, they have significant reductions in the neuronal glutamate transporter mRNAs (EAAT3 and EAAT4). These changes were not associated with changes in relative neuronal density, suggesting a reduction in EAAT mRNA per neuron. Immunohistochemical staining of epileptic human neocortex confirmed the presence of EAAT1 and EAAT2 proteins in astroglial cells and EAAT3 and EAAT4 proteins in human cortical neurons. At the protein level, western blots of the same epileptic and nonepileptic regions for a subset of these patients showed a similar decrease of EAAT3 and EAAT4. Despite no change in EAAT2 mRNA, EAAT2 protein expression was significantly reduced at epileptic foci. CONCLUSION: Regional reductions in EAAT expression at human neocortical epileptic foci could produce increased local glutamate levels that in turn may contribute to both hyperexcitability and the spontaneous generation of epileptic discharges that characterize human epileptic foci.     

Alterations in the Expression of Genes That Encode Subunits of Ionotropic Glutamate Receptors and the Glutamate Transporter in Brain Structures of Rats after Psychogenic Stress

We studied modifications in the glutamatergic system of the brain as a factor in the development of post-traumatic stress disorder. An analysis of mRNA production of NMDA (GluN1, GluN2a, and GluN2b) and AMPA (GluA1 and GluA2) glutamate receptors, as well as the EAAT2 glutamate transporter was performed in the brain of rats subjected to stress associated with contact with a predator (a black-tailed python). Studies were performed in 6 or 24 h as well as in 3, 9, and 25 days after stress. The most-pronounced alterations of expression of all studied genes were revealed 25 days after stress. The level of EAAT2 mRNA increased in the ventral hippocampus. The expression of the genes that encode GluA1 and GluA2 subunits of AMPA receptors decreased in the dorsal and increased in the ventral hippocampus. The changes in the expression of the gene that encodes the GluN2b subunit of the NMDA receptor were also region specific. In the ventral hippocampus and medial prefrontal cortex we observed an increase in the expression of GluN2b mRNA, while it decreased in the dorsal hippocampus. The increased expression of the gene that encodes the GluN2a subunit was found in the amygdala. These alterations may be a mechanism of the development of delayed post-stress neurological–psychiatric impairments.