盐酸多奈哌齐对淀粉样蛋白致痴呆树鼩的治疗作用

目的探讨盐酸多奈哌齐对树鼩侧脑室内注射β-淀粉样蛋白(Aβ)后星形胶质细胞及成熟神经细胞的影响。方法采用GFAP和NeuN免疫组织化学方法检测各组树鼩大脑皮质和海马CA1、CA3、DG区星形胶质细胞和成熟神经元的表达。结果模型组树鼩额叶皮质和海马区GFAP阳性星形胶质细胞数明显高于对照组(P<0.01);治疗组海马(P<0.01)和皮质(P<0.05)GFAP阳性细胞数明显低于模型组。模型组树鼩额叶皮质和海马区NeuN阳性成熟神经元数明显少于对照组(P<0.01);治疗组树鼩海马CA1、CA3区(P<0.05)和额叶皮质(P<0.01)NeuN阳性成熟神经元明显多于模型组。结论盐酸多奈哌齐能抑制Aβ_(1~40)引起的树鼩星形胶质细胞的活化,减轻Aβ对成熟神经元的损伤。     

碘过量对仔鼠海马GFAP阳性星形胶质细胞的影响

目的探讨碘过量与甲状腺激素对仔一代Wistar大鼠大脑海马星形胶质细胞的形态学影响。方法将断乳后1个月Wistar大鼠随机分为5组(NI、5HI、10HI、50HI、100HI),饮用不同浓度的KIO3碘水,饲养3个月后雌雄合笼,取60日龄仔鼠大脑,应用免疫组织化学技术观察海马CA1、CA2、CA3、CA4区星形胶质细胞,并进行形态计量学分析。结果与NI组比较,50HI、100HI组的海马各区GFAP阳性星形胶质细胞面数密度、平均灰度值和阳性细胞的强阳性率均明显降低。结论长期严重碘过量会影响仔鼠甲状腺激素水平,阻碍其大脑海马星形胶质细胞发育,其机理可能与碘过量所致的甲状腺功能低下有关,但大鼠对碘过量有极强的耐受力,当碘摄入量为正常摄入量的50倍以内时,不会影响仔鼠大脑海马星形胶质细胞的发育。     

促红细胞生成素对慢性脑缺血大鼠认知障碍及海马星形胶质细胞的影响

目的 观察促红细胞生成素干预后慢性脑缺血大鼠的空间学习记忆功能及海马星形胶质细胞的变化.方法 结扎大鼠双侧颈总动脉建立慢性脑缺血模型,治疗组术后给予EP01 000 U/kg腹腔内注射5d.术后第8周时3组大鼠Morris水迷宫测试后断头取脑做免疫组化检测观察CA1区胶质纤维酸性蛋白(GFAP)表达.结果 缺血组水迷宫表现同假手术组和EPO治疗组相比有显著差异(P＜0.01).EPO干预能改善慢性脑缺血大鼠的空间学习记忆能力(P＜0.01).缺血组海马CA1区GFAP表达较假手术组相比明显增多,而EPO组海马CA1区GFAP表达同缺血组相比明显降低(P＜0.01).海马CA1区GFAP阳性细胞数与学习记忆能力呈负相关.结论 EPO能显著改善慢性脑缺血大鼠认知障碍,机制可能与减少海马星形胶质细胞增生有关.     

雌激素对Aβ1-40诱导大鼠星形胶质细胞和NOS阳性细胞变化的影响

目的 探讨雌激素对淀粉样β蛋白诱导大鼠星形胶质细胞及NOS阳性细胞变化的影响.方法 于雄性SD大鼠双侧海马注射Aβ1～40,制作AD大鼠病理模型,颈部皮下植入E2,60 d后取脑行冻切片.采用组化和免疫组化方法,观察大鼠海马GFAP与NOS阳性细胞表达的变化,以及雌激素对上述指标的影响.结果 AD大鼠出现海马星形胶质细胞增生、肥大,数量明显多于正常对照组（P＜0.05）,并出现一氧化氮阳性星形胶质细胞;海马一氧化氮神经元数量较正常对照组显著减少（P＜0.05）.E2处理组星形胶质细胞增生不明显,数量明显少于AD模型组（P＜0.05）,且未见一氧化氮阳性星形胶质细胞;海马一氧化氮神经元数量较AD模型组显著增加（P＜0.05）.结论雌激素可减轻神经系统的损伤,对AD有一定防治作用,但其作用机制尚需进一步探讨.     

参麻益智方对双侧颈动脉结扎大鼠海马认知功能的影响

目的观察参麻益智方对双侧颈动脉结扎大鼠行为学及星形胶质细胞和小胶质细胞的影响。方法将60只Wistar大鼠随机分为假手术组(Sham)、双侧颈动脉结扎组(2-VO)、多奈哌齐组(0.5 mg/kg)、中药低剂量组(3.3 mg/kg)、中药中剂量组(6.6 mg/kg)和中药高剂量组(16.5 mg/kg),每组10只。灌胃给药4周后进行水迷宫实验,并观察海马CA1区星形胶质细胞及小胶质细胞的形态改变。结果 2-VO组大鼠逃避潜伏期较Sham组明显延长(P<0.05),目标象限停留时间百分比明显下降(P<0.05);多奈哌齐组及中药高剂量组、中剂量组大鼠逃避潜伏期较2-VO组明显缩短(P<0.05),目标象限停留时间百分比显著延长(P<0.05)。2-VO组大鼠海马CA1区星形胶质细胞及小胶质细胞较Sham组增多,胞体增大。给药后,多奈哌齐组与中药高剂量组、中剂量组星形胶质细胞及小胶质细胞较2-VO组数量减少,胞体变小。结论参麻益智方可改善大鼠学习记忆能力,减轻双侧颈动脉硬化大鼠海马CA1区星形胶质细胞和小胶质细胞的增生和激活,从而改善大鼠认知功能。     

糖尿病大鼠脑缺血再灌注后细胞外信号调节激酶1/2表达与海马CA4区神经元凋亡

目的 探讨糖尿病大鼠脑缺血再灌注后神经元细胞外信号调节激酶(extracellularsignal-regulated kinase,ERK)1/2表达及其意义.方法 72只健康成年SD大鼠随机分假手术组、正常血糖脑缺血组和糖尿病腑缺血组,每组根据缺血再灌注不同时点分为缺血 15 min再灌注1 h、3 h,6 h亚组,每个亚组6只.采用链脲佐菌素诱导糖尿病,双血管闭塞联合放血法建立糖尿病大鼠全脑缺血模型.应用TUNEL和免疫组化方法观察海马CA4区神经元凋亡和磷酸化ERK1/2表达.结果 糖尿病脑缺血组在缺血 15 min、冉灌注1 h,3 h,6 h各时间点海马CA4区神经元凋亡发生率均明显高于正常血糖脑缺血组(P<0.05);糖尿病脑缺血组在各时间点磷酸化ERK1/2均有较高表达,在再灌注1 h和3 11时均明显高于正常血糖组(P<0.01).结论 ERK1/2可能参与了糖尿病加重脑缺血冉灌注后神经元损伤的机制.     

糖尿病大鼠脑缺血再灌注后细胞外信号调节激酶1/2表达与海马CA4区神经元凋亡

目的 探讨糖尿病大鼠脑缺血再灌注后神经元细胞外信号调节激酶(extracellularsignal-regulated kinase,ERK)1/2表达及其意义.方法 72只健康成年SD大鼠随机分假手术组、正常血糖脑缺血组和糖尿病腑缺血组,每组根据缺血再灌注不同时点分为缺血 15 min再灌注1 h、3 h,6 h亚组,每个亚组6只.采用链脲佐菌素诱导糖尿病,双血管闭塞联合放血法建立糖尿病大鼠全脑缺血模型.应用TUNEL和免疫组化方法观察海马CA4区神经元凋亡和磷酸化ERK1/2表达.结果 糖尿病脑缺血组在缺血 15 min、冉灌注1 h,3 h,6 h各时间点海马CA4区神经元凋亡发生率均明显高于正常血糖脑缺血组(P<0.05);糖尿病脑缺血组在各时间点磷酸化ERK1/2均有较高表达,在再灌注1 h和3 11时均明显高于正常血糖组(P<0.01).结论 ERK1/2可能参与了糖尿病加重脑缺血冉灌注后神经元损伤的机制.     

脑缺血对阿尔茨海默病大鼠海马内病理特征及炎性反应的影响

目的观察脑缺血后阿尔茨海默病(AD)大鼠海马内的病理特征、炎性细胞及细胞因子表达的变化,探讨脑缺血在AD病程进展中的作用及机制。方法经Morris水迷宫筛选SD大鼠30只.随机分为AD组、AD+脑缺血组、对照组,每组10只。大鼠海马注射凝聚态淀粉β样蛋白_(1-10)成功建立AD模型后.海马注射内皮素-1建立脑缺血条件,观察脑缺血后AD大鼠海马内淀粉β样蛋白(Aβ)的沉积及神经元丢失的变化,采用免疫组织化学、原位杂交和RT-PCR检测脑缺血后AD大鼠海马内星形胶质细胞的数量和白细胞介素1β(IL-1β)、TNF-α表达的变化。结果与对照组比较,AD组和AD+脑缺血组大鼠海马星形胶质细胞数量、IL-1β和TNF-α表达均显著增多(P<0.01)。结论脑缺血促进了AD大鼠海马内Aβ的沉积和神经元的丢失,提示脑缺血可促进AD的病程进展,星形胶质细胞、IL-1β和TNF-α参与了这一过程。     

大鼠在空间辨别性学习记忆时海马CA3区星形胶质细胞的变化

目的观察大鼠在空间辨别性学习记忆时海马CA3区星形胶质细胞的变化,从而探讨星形胶质细胞与空间辨别性学习记忆的关系。方法以水迷宫法建立大鼠空间辨别性学习记忆动物模型,用星形胶质细胞GFAP免疫组织化学方法检测星形胶质细胞的数量和星形胶质细胞GFAP反应产物的AOD数值。结果具有空间辨别性学习记忆能力的大鼠海马星形胶质细胞的数量和星形胶质细胞GFAP反应产物的AOD数值均比对照组增加(P0.05)。结论星形胶质细胞参与空间辨别性学习记忆的过程,并与记忆的巩固有关。     

短暂脑缺血对大鼠海马脑区锥体神经元外向整流氯通道功能的影响

目的 研究短暂前脑缺血对大鼠海马CA1和CA3脑区锥体神经元外向整流氯通道功能的影响.方法 采用膜片钳全细胞技术,在成年大鼠海马脑区锥体神经元上记录到可以被氯通道阻断剂DIDS阻断,具有外向整流特性的氯通道.结果 15 min前脑缺血再灌注6h和24 h后,海马CA1区锥体神经元氯通道电流持续性增强,而CA3区锥体神经元活动无明显改变.结论 氯通道功能增强可能参与海马CA1区锥体神经元在脑缺血后的迟发性死亡过程,并且为治疗缺血性脑损伤提供了新的手段.     

鼠脑出血后部分脑区内皮素-1表达与脑水含量变化

目的　探讨ET 1在脑出血继发性脑损伤中的作用。方法　通过脑内注射胶原酶建立大鼠脑出血模型 ,采用免疫组织化学技术观察脑出血后脑内ET 1表达与脑出血灶周围组织水肿之间的关系。结果　给大鼠尾壳核注射胶元酶 0 5IU ,4h后脑水含量即明显升高 ,2 4h达高峰 ,与此同时ET 1在皮层、海马等脑区的表达明显增多 ,并于2 4h达高峰。结论　大鼠脑出血后脑内内皮素过度表达可能是血肿周围存在水肿和继发性缺血的重要因素之一     

Melatonin ameliorates hippocampal nitric oxide production and large conductance calcium-activated potassium channel activity in chronic intermittent hypoxia

Melatonin protects against hippocampal injury induced by intermittent hypoxia (IH). IH-induced oxidative stress is associated with decreases in constitutive production of nitric oxide (NO) and in the activity of large conductance calcium-activated potassium (BK) channels in hippocampal neurons. We tested the hypothesis that administration of melatonin alleviates the NO deficit and impaired BK channel activity in the hippocampus of IH rats. Sprague-Dawley rats were injected with melatonin (10 mg/kg, i.p.) or vehicle before daily IH exposure for 8 hr for 7 days. The NO and intracellular calcium ([Ca2+]i) levels in the CA1 region of hippocampal slices were measured by electrochemical microsenor and spectrofluorometry, respectively. The activity of BK channels was recorded by patch-clamping electrophysiology in dissociated CA1 neurons. Malondialdehyde levels were increased in the hippocampus of hypoxic rats and were lowered by the melatonin treatment. Levels of NO under resting and hypoxic conditions, and the protein expression of neuronal NO synthase (nNOS) were significantly reduced in the CA1 neurons of hypoxic animals compared with the normoxic controls. These deficits were mitigated in the melatonin-treated hypoxic rats with an improved [Ca2+]i response to acute hypoxia. The open probability of BK channels was decreased in the hypoxic rats and was partially restored in the melatonin-treated animals, without alterations in the expression of channel subunits and unitary conductance. Acute treatment of melatonin had no significant effects on the BK channel activity or on the [Ca2+]i response to hypoxia. Collectively, these results suggest that melatonin ameliorates the constitutive NO production and BK channel activity via an antioxidant mechanism against an IH-induced down-regulation of nNOS expression in hippocampal neurons.     

蛛网膜下腔出血后海马区微血管痉挛及血管内转染一氧化氮合酶基因的影响

目的研究蛛网膜下腔出血(SAH)后海马CA1区神经元及微血管的变化,观察血管内转染内皮型一氧化氮合酶(eNOS)基因后,海马CA1神经元及微血管改变,探讨eNOS基因转染预防脑血管痉挛的作用。方法 24只兔随机分为对照组、SAH组、转染携带eNOS基因重组腺病毒组(AdeNOS组)。每组8只。采用枕大池二次注血法制备兔SAH后脑血管痉挛模型。兔于首次注血后7d进行灌注固定,留取海马区脑组织标本,在电镜和光镜下观察海马神经元及微血管的变化。结果光镜下SAH组海马CA1区神经元较对照组明显减少,微血管周围间隙增宽,管腔狭窄,管壁增厚;电镜下SAH组海马神经元细胞肿胀,结构不完整,细胞核固缩,线粒体空泡化;AdeNOS组损伤较SAH组明显减轻。结论 SAH后脑血管痉挛可引起海马CA1区神经元变性,可能与海马区微血管痉挛改变有关,eNOS基因转染可明显减轻海马神经元损伤,预防SAH后脑血管痉挛的发生。     

电针治疗对大鼠脑缺血再灌注中Annexin A1表达的影响

目的探讨电针治疗在大鼠脑缺血再灌注损伤中对Annexin A1表达的影响。方法 SD大鼠32只,随机分为对照组、缺血再灌注组、电针组、假手术组,每组8只。检测Annexin A1在大鼠脑组织中的表达变化及AnnexinA1转位结果。结果大鼠大脑中动脉栓塞60 min再灌注24h后,可出现明显的神经缺损性行为,在脑缺血前后以电针治疗可明显改善大脑损伤性行为异常。在海马CA1、CA2、CA3、齿状回、皮质区,缺血再灌注组大鼠Annex-in A1的表达较对照组明显升高,电针组大鼠Annexin A1的表达较缺血再灌注组明显下降(P<0.05)。在海马CA1、CA3、皮质区,缺血再灌注组大鼠Annexin A1核转位和膜转位较对照组明显上升;在海马CA1、CA3区,电针组大鼠Annexin A1核转位和膜转位较缺血再灌注组明显下降(P<0.05)。结论脑缺血再灌注后Annexin A1表达上调,Annexin A1出现核转位和膜转位现象,电针可以逆转Annexin A1表达和转位。电针有可能通过调节Annexin A1的核转位和膜转位来改变神经元的凋亡。     

大鼠海马神经元及其线粒体增龄性改变的形态计量分析

目的探讨大鼠海马神经元及其线粒体形态结构增龄性改变的程度及性质。方法应用组织化学及电镜技术，通过计算机图像分析系统对海马神经元及其线粒体结构进行形态计量分析。结果海马ＣＡ１和ＣＡ３区神经元随增龄出现细胞皱缩，ＣＡ３区神经元数密度在老年组较青年组显著减少（Ｐ＜０．０５），ＣＡ１区神经元数密度各月龄组之间差异无显著性（Ｐ＞０．０５）。ＣＡ３区神经元胞体内线粒体体密度、数密度、比表面及嵴膜密度随增龄而减少，线粒体平均体积及平均截面积随增龄而增大。结论海马神经元及其线粒体形态结构随增龄发生显著性改变，这些形态结构的改变可能是大鼠海马老化的指征。     

Long-term observations in gerbil brain following transient cerebral ischemia: Autoradiographic and histological study

We investigated the long-term changes that occur in the gerbil brain following transient cerebral ischemia using histology and receptor autoradiography. Transient ischemia was induced for 3 and 10 min, and animals were allowed to survive for 8 months. A histological study showed that 3-min ischemia caused neuronal damage and mild atrophy only in the hippocampal CA1 sector, and that 10-min ischemia produced severe neuronal damage and marked shrinkage in the hippocampal CA1 and CA3 sectors. Furthermore, severe neuronal damage was seen in the striatum after 10-min ischemia. Autoradiography study revealed that 3-min ischemia caused a significant reduction in [³H] naloxone binding in the frontal cortex, striatum, dentate gyrus, and thalamus, whereas [³H]SCH 23390 and [³H] forskolin binding was not significantly altered in all regions, In contrast, 10-min ischemia produced marked alteration in these binding sites in the striatum, hippocampus, thalamus, and substantia nigra. The alteration was especially notable in the hippocampal region and substantia nigra. These results indicate that hippocampal damage after transient ischemia, compared with that in other regions, is not static, but particularly progressive. Furthermore, they demonstrate a reduction in adenylate cyclase system in the striatum and substantia nigra after transient ischemia. Moreover, our results suggest that long-term survival after ischemia may induce synaptic modification of neurotransmitter and adenylate cyclase system in the hippocampus.     

Neuronal populations of rat cerebral cortex and hippocampus expressed a higher density of L-type Ca 2+ channel than corresponding cerebral vessels

Dihydropyridine (DHP)-type Ca2+ antagonists block primarily L-type Ca2+ channels and are used in the therapy of hypertension. They were also proposed for the treatment of several central nervous system disorders. In brain, these compounds bind both neuronal and vascular Ca2+ channels, but no studies have evaluated comparatively their density at neuronal and vascular level. This study has analyzed the pharmacological profile and the anatomical localization of L-type Ca2+ channels in rat frontal cortex, hippocampus and in forebrain pial and intracerebral arteries by radioligand binding assay and high resolution light microscope autoradiography. The DHP derivative [3H]nicardipine was used as a radioligand. Binding of [3H]nicardipine was consistent with the labeling of L-type Ca2+ channels. In frontal cortex, the highest density of binding sites was found in nerve cell body region, followed by the neuropil and the wall of intracerebral arteries. In hippocampus, the density of binding sites was higher in the nerve cell body region than in the neuropil of CA1, CA3, and CA4 subfields. In the dentate gyrus, a higher density of silver grains was developed in neuropil than in nerve cell body of granule neurons. With the exception of dentate gyrus, neuronal binding sites were more expressed than vascular binding sites in the hippocampus. In pial arteries [3H]nicardipine binding density decreased concomitant with the reduction of vessel diameter, whereas in intracerebral arteries [3H]nicardipine binding density displayed an opposite pattern. The above findings indicate that in brain the density of neuronal L-type Ca2+ channels was significantly higher than that of vascular ones. This may account for more pronounced neuronal than vascular effects after pharmacological manipulation of cerebral Ca2+ channels.     

大鼠脑缺血后海马CA1区脑红蛋白表达的变化及肢体缺血预处理对其影响

目的 观察青年和老年大鼠脑缺血后海马CA1区脑红蛋白(Ngb)表达的变化及肢体缺血预处理(LIP)对其影响. 方法 将凝闭双侧椎动脉的青年和老年大鼠均随机分为脑缺血组和脑缺血+LIP组.采用反转录聚合酶链反应(RT-PCR)和Western blot法检测海马CA1区NgbmRNA和蛋白表达,硫堇染色观察海马CA1区锥体神经元迟发性死亡(DND)情况. 结果 青年脑缺血组、青年脑缺血+LIP组、老年脑缺血组、老年脑缺血+LIP组的Ngb mRNA和蛋白表达分别为0.16±0.02和0.32±0.07、0.52±0.04和0.91±0.06、0.09±0.01和0.22±0.08、0.21±0.01和0.66±0.06.表明老年大鼠脑缺血后海马CA1区Ngb mRNA和蛋白表达较青年脑缺血大鼠降低(P<0.05),LIP可上调青年和老年大鼠脑缺血后海马CA1区Ngb mRNA和蛋白表达(P<0.05),但对老年大鼠的上调作用低于青年大鼠(P<0.05).硫堇染色显示,海马CA1区神经元密度青年脑缺血组,青年脑缺血+LIP组、老年脑缺血组和老年脑缺血+LIP组分别为(38.8±10.9)、(171.5±16.9)、(21.2±12.2)个/mm和(102.7±15.4)个/mm.表明老年大鼠LIP预防脑缺血引起的海马CA1区锥体神经元DND的作用小于青年大鼠. 结论 老年大鼠脑缺血后Ngb的表达及LIP对其上调作用较青年大鼠明显减弱,这可能是老年大鼠脑缺血后损伤较重和LIP对老年大鼠脑缺血保护作用较弱的原因之一.     

Tracking the estrogen receptor in neurons: Implications for estrogen-induced synapse formation

Estrogens (E) and progestins regulate synaptogenesis in the CA1 region of the dorsal hippocampus during the estrous cycle of the female rat, and the functional consequences include changes in neurotransmission and memory. Synapse formation has been demonstrated by using the Golgi technique, dye filling of cells, electron microscopy, and radioimmunocytochemistry. N-methyl-d-aspartate (NMDA) receptor activation is required, and inhibitory interneurons play a pivotal role as they express nuclear estrogen receptor alpha (ERalpha) and show E-induced decreases of GABAergic activity. Although global decreases in inhibitory tone may be important, a more local role for E in CA1 neurons seems likely. The rat hippocampus expresses both ERalpha and ERbeta mRNA. At the light microscopic level, autoradiography shows cell nuclear [3H]estrogen and [125I]estrogen uptake according to a distribution that primarily reflects the localization of ERalpha-immunoreactive interneurons in the hippocampus. However, recent ultrastructural studies have revealed extranuclear ERalpha immunoreactivity (IR) within select dendritic spines on hippocampal principal cells, axon terminals, and glial processes, localizations that would not be detectable by using standard light microscopic methods. Based on recent studies showing that both types of ER are expressed in a form that activates second messenger systems, these findings support a testable model in which local, non-genomic regulation by estrogen participates along with genomic actions of estrogens in the regulation of synapse formation.