家兔脑不完全缺血后海马的组织学变化

家兔颈总动脉单侧结扎,双侧不同的时结扎和双侧同时结扎后,均可造成不同程度的脑不完全缺血,海马组织学的主要变化是海马吕间部多型细胞层的小血管瘀血,引起边缘部的锥体细胞层毛细血管贫血,锥体细胞供血不良,使其轴突萎缩。海马ＣＡ３区突触小体内的线粒体及颗粒消失,突触小泡减少,内移及致密化,这种变化随结扎程度的不同逐渐加深,尤以双侧同时结扎最为明显。为颈总动脉结扎后影响学习和记忆提供了组织学依据。     

新生小鼠缺氧缺血性脑损伤模型的制作研究

目的：通过对动物模型的制作模拟新生儿围产期缺氧缺血性脑损伤,研究其脑组织病理变化,为新生儿缺氧缺血性脑损伤的病理生理的研究以及进一步有效的治疗提供实验基础。方法：将40只7d新生昆明小鼠分四组,分别为正常组（A组）、单侧颈总动脉结扎组（B组）、单侧颈总动脉结扎＋缺氧组（C组）和双侧颈总动脉结扎组（D组）。单侧颈总动脉结扎组（B组）行右侧颈总动脉结扎;单侧颈总动脉结扎＋缺氧组（C组）行右侧颈总动脉结扎后将其置于20℃的恒温50mL密闭容器中,分不同的时间将其取出;双侧颈总动脉结扎组（D组）行双侧颈总动脉结扎,各组术后均送回母鼠身边继续母乳喂养,三天后再作病理检测。结果：行单侧颈总动脉结扎加缺氧60min时,小鼠结扎侧皮质及海马区出现病理改变,随着缺氧时间延长（90rain、100min、120min）病变范围逐渐扩大,病理改变越明显。结论：本实验显示单侧颈总动脉结扎同时缺氧一定时间可以导致小鼠脑组织损伤,脑细胞发生病理改变,且皮层及海马区域的神经细胞对缺氧缺血最为敏感,从而为进一步研究新生儿缺氧缺血性脑损伤提供了较为可靠的模型。     

青霉素诱发癫痫及耳穴电针后大鼠前脑生长抑素mRNA的变化

应用地高辛标记的生长抑素（ＳＳ）ＲＮＡ探针原位杂交法观察大鼠在青霉素诱发的癫痫及耳穴电针抑制癫痫发作后有关的脑区中ＳＳｍＲＮＡ含量的变化。结果显示,青霉素致痫后２４小时梨状皮质、额叶皮质、扣带回、隔外侧核、杏仁基底核海马ＣＡ１－ＣＡ４区和齿状回颗粒细胞层、多形层等脑区ＳＳｍＲＮＡ的表达显著增加,与正常对照组比较Ｐ＜００５。耳穴电针抑痫（８０１００ＨＺ,６ｍＡ）后额叶皮质、杏仁基底核、海马齿状回、前梨状皮质ＳＳｍＲＮＡ的表达明显减少,Ｐ＜００５。提示前脑结核中的生长抑素与青霉素致痫和耳针抑痫有关。     

血管性痴呆大鼠模型制作方法的改良

目的对血管性痴呆(VD)大鼠模型的造模方法进行改进,使血管性痴呆的实验研究更加科学可靠。方法采用"反复夹闭颈动脉加注射硝普钠降压再加单侧永久结扎颈总动脉法"制备VD大鼠模型,并用脑复康(吡拉西坦)加以模型验证。实验从大鼠行为学和组织病理两个方面评价VD模型。结果实验结果显示:对比假手术组,模型组大鼠定位航行潜伏期延长,空间搜索穿越平台次数减少,海马病理切片显示:细胞数量较少、细胞轮廓模糊皱缩、胞质深染、核不清晰;脑复康阳性药物对照组上述指标明显改善。结论硝普钠注射量为2.0 mg/kg时,手术室温控制在28℃且术后24 h内控制在25℃,大鼠状态稳定,死亡数减少;术中反复阻断三次双侧颈总动脉后直接永久性结扎左侧颈总动脉,可以切断大约三分之一的脑供血,造成慢性脑供血不足状态,更接近VD发病机制。     

血管性痴呆动物模型制作方法的改良

目的对大鼠血管性痴呆双侧颈总动脉永久性结扎模型（permanent bilateral common carotid arteryocclusion,2VO）进行改良,以提高模型动物存活率。方法采取改良造模方法（间隔7d分2次结扎双侧颈总动脉）和传统的2VO方法（同时结扎双侧颈总动脉）建立血管性痴呆模型,观察并比较2种方法大鼠的存活率、学习记忆能力改变及病理形态学变化。结果术后7 d,改良模型组动物存活率（86.7%）明显高于传统模型组（40.0%）（P〈0.05）。术后8 w与12 w,与假手术组比较,两种方法模型组逃避潜伏期均明显延长（P〈0.05）,而改良法与传统法造模组之间相比较无显著性差异。HE染色显示：改良法与传统法造模组的大鼠海马区神经元有相似程度的明显变性、坏死和凋亡。结论 2VO改良造模法是降低大鼠血管性痴呆模型动物死亡率的成功方法,值得进一步研究、推广。     

凝闭双侧椎动脉预处理对大鼠全脑缺血损伤的防护作用

目的：观察凝闭双侧椎动脉与夹闭双侧颈总动脉之间的不同时间间隔对Pulsinelli四血管闭塞法全脑缺血模型的影响、以及在凝闭单侧椎动脉的基础上夹闭双侧颈总动脉后的脑缺血的特点。方法：84只Wistar大鼠．随机分为以下4组：对照组、双侧椎动脉凝闭组、全脑缺血组、单侧椎动脉凝闭＋双侧颈总动脉夹闭组。全脑缺血组中,根据凝闭双侧椎动脉与夹闭双侧颈总动脉之间的时间间隔不同,又分为24h间隔、48h间隔和72h间隔3个亚组。观察大鼠脑缺血过程中的反应包括瞳孔散大、对光反射等情况,脑缺血后恢复翻正反射所需要的时间、以及动物的一般状况,并应用硫堇染色法观察海马CA1区锥体神经元迟发性死亡的情况：结果：全脑缺血72h间隔亚组的大鼠,脑缺血过程中的反应、脑缺血后的一般状况和锥体神经元迟发性死亡程度均明显重于全脑缺血24h间隔亚组及48h间隔亚组,但24h间隔亚组与48h间隔亚组之间无显著差异一单侧椎动脉凝闭＋双侧颈总动脉夹闭组大鼠的凝闭侧瞳孔散大、对光反射消失、海马CA1区神经元大量死亡;而未凝闭侧未见上述相关变化。结论：凝闭双侧椎动脉本身也具有脑缺血预处理样作用,对其后48h内夹闭双侧颈总动脉所致的严重脑缺血具有一定程度的保护作用;大鼠椎动脉对脑干及海马的血液供应均存在明显的同侧优势效应,     

辣椒素引起脑干内心血管活动相关核团中c-fos的表达

在１６只切断两侧缓冲神经的大鼠,观察颈总动脉注射辣椒素对脑干内心血管活动相关核团ｃ－ｆｏｓ原癌基因表达的影响。在剂对照组大鼠脑干,仅见少数Ｆｏｓ蛋白样免疫反应（ＦＬＩ）神经元。与对照组相比,颈总动脉注射辣椒素（１０μｍｏｌ,０．１ｍｌ）时,脑干内巨细胞旁外侧核（ＰＧＬ）、蓝斑（ＬＣ）、最后区（ＡＰ）和孤束核（ＮＴＳ）等部位的ＦＬＩ神经元显著增加,而中脑中央灰质（ＰＡＧ）和中缝核群（ＲＮ）的ＦＬＩ神     

消栓通胶囊抗脑缺血作用的实验研究

目的:观察消栓通胶囊对双侧颈总动脉结扎的大鼠脑缺血的保护作用;对小鼠断头后存活时间的影响.方法:采用结扎大鼠双侧颈总动脉以造成脑缺血模型,观察消栓通胶囊的药理作用.结果:①a.消栓通胶囊对双侧颈总动脉结扎大鼠脑含水量及脑指数有显著影响,消栓通胶囊三个剂量组(0.20 g/kg、0.40 g/kg、0.80 g/kg),脑含水量明显减少,与模型组有显著差异(P＜0.05或P＜0.01).b.组织病理学检查表明消栓通胶囊组的脑组织神经细胞浓缩及深染较脑缺血模型组明显减轻;神经胶质细胞肿胀及间质疏松程度均明显轻于模型组.②消栓通胶囊三个剂量组(0.20 g/kg、0.40 g/kg、0.80 g/kg)均能明显降低全血粘度值,与模型组比较有明显差异(P＜0.05或P＜0.01);③消栓通胶囊三个剂量组(025g/kg、0.50g/kg、1.00 g/kg)给药14d,与正常组比较可延长小鼠断头喘气的时间(P＜0.05或P＜0.01).结论:消栓通胶囊对大鼠结扎双侧颈总动脉所致脑缺血损伤具有明显的保护作用.     

胶质细胞谷氨酸转运体-1反义寡核苷酸对脑缺血预处理神经保护效应的抑制作用

本研究应用胶质细胞谷氨酸转运体-1(glial glutamate transporter-1,GLT-1)的反义寡核苷酸(antisense oligo-deoxynucleotides,AS-ODNs)抑制Wistar大鼠GLT-1蛋白的表达,观察其对脑缺血预处理(cerebral ischemic preconditioning.CIP)增强脑缺血耐受作用的影响,探讨GLT-1在CIP诱导的脑缺血耐受中的作用.将凝闭双侧椎动脉的Wistar大鼠随机分为7组:(1)Sham组:只暴露双侧颈总动脉,不阻断血流;(2)CIP组:夹闭双侧颈总动脉3 min;(3)脑缺血打击组:夹闭双侧颈总动脉8 min;(4)CIP 脑缺血打击组:夹闭双侧颈总动脉3 min作为CIP,再灌注2 d后,夹闭双侧颈总动脉8min;(5)双蒸水组:于分离暴露双侧颈总动脉(但不夹闭)前12 h、后12 h及后36 h右侧脑室注射双蒸水,每次5 μL,其它同sham组;(6)AS-ODNs组:于分离暴露双侧颈总动脉(但不夹闭)前12 h、后12 h及后36 h右侧脑室注射GLT-1 AS-ODNs溶液,每次5 μL,其它同sham组,再根据AS-ODNs的剂量进一步分为9 nmol和18 nmol 2个亚组;(7)AS-ODNs CIP 脑缺血打击组:于CIP前12 h、后12 h及后36 h右侧脑室注射GLT-1 AS-ODNs溶液,每次5 μL,其它同CIP 脑缺血打击组,根据AS-ODNs的剂量进一步分为9 nmol和18 nmol 2个亚组.Western blot分析法观察GLT-1蛋白的表达,硫堇染色观察海马CA1区锥体神经元迟发性死亡(delayed neuronal death,DND)情况.Western blot分析显示,侧脑室注射GLT-1 AS-ODNs可剂量依赖性地抑制大鼠海马CA1区GLT-1蛋白表达.硫堇染色显示,sham组和CIP组海马CA1区未见明显的DND;脑缺血打击组海马CA1区有明显的DND:预先给予CIP可显著对抗脑缺血打击引起的DND,表明CIP可以诱导海马CA1区神经元产生缺血性耐受,对抗脑缺血打击引起的DND;而在GLT-1 AS-ODNs CIP 脑缺血打击组,侧脑室注射GLT-1 AS-ODNs后,大鼠海马CA1区出现了明显的DND,表明GLT-1 AS-ODNs通过抑制大鼠GLT-1蛋白表达从而减弱CIP对抗脑缺血打击的神经保护作用.以上结果进一步证实了GLT-1参与CIP诱导的脑缺血耐受.     

后肢远程缺血预处理对小鼠全脑缺血再灌注的保护作用及机理

目的:探讨肢端远程缺血预处理(limb remote ischemic preconditioning)对小鼠全脑缺血再灌注损伤的保护作用及其机制.方法:36只雄性C57小鼠,随机分为3组,即假手术组、对照组和LRPC预处理组,每组12只,假手术组分离双侧颈总动脉不结扎;对照组分离颈总动脉后结扎双侧颈总动脉,20 min后松线;LRPC组首先暴露双侧股动脉,然后结扎1 min,松开5 min,进行3个循环,最后结扎颈总动脉20min后松线.观察和比较各组小鼠海马神经元形态,MPO及炎性因子IL-1β、TNF-α和IL-10含量的变化.结果:再灌注24 h后,LRPC可明显抑制神经元形态的改变(P＜0.05),减少MPO、IL-1β和TNF-α含量,而增加抗炎因子IL-10的含量.结论:LRPC可显著减轻脑缺血再灌注损伤,可能与其降低海马组织TNF-o,IL-1β的含量,增加IL-10的含量有关.     

Chronic Cerebral Hypoperfusion Induces Transient Reversible Monoaminergic Changes in the Rat Brain

Chronic restriction of cerebral blood flow in hypoperfused Wistar rats has been proposed as a new model of cerebrovascular-type dementia. Using this model, we have investigated central monoaminergic neuronal systems that are closely related to higher brain function. Monoamine and monoamine-metabolite levels were determined, as relative monoaminergic markers, at 1 day and 1,3,6 and 12 weeks after the bilateral occlusion of common carotid arteries. Dopaminergic changes in the frontal cortex and striatum were observed in hypoperfused rats at 1–3 weeks following occlusion. Serotonergic changes were recognized at four brain regions examined (frontal cortex, hippocampus, striatum and thalamus+midbrain). In particular, the immediate enhancement of serotonin turnover in the striatum appeared to influence the reaction to the acute ischemic attack such as vasoconstriction produced by hypoperfusion. Our findings suggest that chronic cerebral hypoperfusion induces transient reversible changes in central monoaminergic neuronal function within three weeks of ligation of carotid arteries. This time interval seems to represent a turning point in the process of chronic cerebral hypoperfusion-induced progressive brain injury.     

Restoration of blood supply and the intensity of phospholipid metabolism in different rat brain regions during the postischemic period]

Fifteen min after resumption of the blood flow in the common carotid arteries the arrest of which was caused by ligation, a considerable intensification of the blood supply in the hemispheres, diencephalon and the midbrain and its simultaneous reduction in the cerebellum and the medulla oblongata occurred. Sixty min later the cerebral blood supply in all the parts of the brain under study recovered completely, except the hemispheres. The complete postischemic recovery of the phospholipid metabolism intensity occurred in the brain regions showing a considerable diminution of the phospholipid metabolism during the ischemic period.     

Cerebrovascular reserve in the cat after acute bilateral carotid occlusion

Cerebral blood flow in the cat was studied before and after acute bilateral common carotid occlusion under normocapnic and hypercapnic conditions and after induced hypotension. Regional blood flow to different brain structures was studied with the microsphere method. Local blood flow in the caudate nucleus, the cerebral cortex and medulla oblongata was studied with H2-polarography. Although the blood flow to the anterior brain regions is significantly decreased after bilateral common carotid occlusion, their blood supply is kept above ischaemic levels by re-distribution of the vertebrobasilar flow. Cerebrovascular reserve in anterior brain regions, however, is lost as indicated by the severe impairment of both the flow response to hypercapnia and to blood pressure decrease. After bilateral common carotid occlusion paradoxical CO2-reactions, indicating intracerebral steal, were seen in the caudate nucleus. In posterior brain regions resting blood flow, flow-reaction to hypercapnia and to hypotension are better preserved under these conditions. Measurement of the CBF responses to induced hypercapnia is a dependable test for appreciation of cerebrovascular reserve after cerebrovascular occlusion but may be potentially hazardous where local flow is close to ischaemic levels.     

Post-ischemic administration of the acetylcholinesterase inhibitor ENA-713 prevents delayed neuronal death in the gerbil hippocampus

We examined by morphological methodology the effect of (S)-N-ethyl-3-[(1-dimethyl-amino)ethyl]-N-methyl-phenylcarbamate hydrogentartrate (ENA-713), an acetylcholinesterase (AChE) inhibitor, on ischemia-induced neuronal death in the gerbil hippocampus due to a 5-min ligation of bilateral common carotid arteries after light ether anesthesia. Pyramidal cells had been decreased to 27% of sham-operated controls and the number of hypertrophic astrocytes expressing glial fibrillary acidic protein (GFAP) markedly increased in the hippocampal CA1 subfield 14 days after ischemia. However, post-ischemic administration of ENA-713 (three times 0.2 mg/kg, i.p.) significantly ameliorated this ischemia-induced decrease in the number of pyramidal cells by 47% of sham-operated controls, furthermore, it reduced the ischemia-induced accumulation of GFAP-positive astrocyte in the CA1 region. Together with previous results showing that ENA-713 protected against the ischemia-induced cholinergic abnormalities in the gerbil brain and improved cholinergic dysfunctions in the senescent rat brain, our present findings suggest that ENA-713 prove to be useful for treatment with senile dementia such as cerebrovascular dementia.     

Blood Pressure-Independent Factors Determine the Susceptibility to Delayed Neuronal Death in the Stroke-Prone Spontaneously Hypertensive Rats

The stroke-prone spontaneously hypertensive rat (SHRSP) is vulnerable to delayed neuronal death (DND) in the CA1 subfield of the hippocampus after the transient forebrain ischemia by the occlusion of the bilateral carotid arteries. The present study was designed to show that the genetic factors independent of high blood pressure contributed to the high incidence of DND in SHRSP. Male rats of the four strains, SHRSP/Izm, SHRSP/Ngsk, SHR/Izm and a congenic strain for the blood pressure quantitative trait locus on chromosome 1 [SHRSP.WKY-(D1Wox29-D1Arb21)/Izm]were used in the experiments. At 13 weeks of age, the bilateral carotid arteries of rats were occluded for 10 min under anesthesia with their body temperature kept at 37°C. Seven days after the transient ischemia, the loss of the pyramidal cells in the CA1 was evaluated histologically. In some experiments, the blood flow was monitored with a laser Doppler flowmeter during the transient ischemia. The blood pressure in SHRSP/Izm was significantly greater than that in the other three strains. The incidence of DND, however, was not significantly different among SHRSP/Izm, SHRSP/Ngsk and the congenic strain (82, 74 and 65%, respectively), while SHR/Izm showed a significantly lower incidence (20%). Neither a significant correlation between the incidence of DND and the blood flow reduction during the occlusion, nor a significant inter-strain difference in the blood flow reduction was observed. The genetic factors independent of high blood pressure may contribute to the greater susceptibility to DND in SHRSP.     

Arterial adaptations to altered blood flow

Arterial remodeling in response to altered blood flow is believed to be critical to vascular adaptations to developmental, physiological, pathological, and therapeutically induced changes in blood flow. To assess this remodeling, we used left-to-right carotid anastomosis to increase blood flow in the right common carotid arteries of adult rabbits by 60%. After 2 months, these vessels exhibited no compensatory enlargement. In contrast, the same procedure performed in 5- to 6-week-old weanling rabbits resulted in accelerated growth of the vessels: diameters exceeded those of control arteries by 19% after 2 months. Common carotid arteries in adult rabbits remodeled to produce a diameter reduced by 23% when blood flow was reduced by 63% by external carotid ligation. This adaptation restored shear stress exerted on the vessel wall to control levels. The reduced diameter was not reversed when the vessels were maximally dilated with nitroprusside, adenosine, and forskolin; however, normal diameters were restored within 1 week when normal blood flows were reestablished. Thus, the adult arteries did not respond to increased blood flow produced by the anastomosis, but this procedure did reverse adaptations to decreased flow. In contrast, immature arteries were responsive to this increase in blood flow, even in the absence of prior flow modulation.     

Local cerebral glucose utilization in the hippocampus of old rats

Summary The local cerebral glucose utilization (LCGU) was measured in the different areas and layers of the Ammon's horn and dentate gyrus of young adult (3 to 4-month-old) rats, and of 27-month-old rats with proven cognitive deficits. The LCGU was determined by quantitative [¹⁴C]2-deoxyglucose autoradiography. Compared to young animals, in the old rats the LCGU was significantly reduced by 12% to 15% in the oriens layers of CA1 and CA2, the pyramidal layers of the CA sectors 1–3, the radiatum and lacunosum-molecular layers of CA2 and CA3 and in the lucidum layer of CA3. The LCGU values of all the other layers of the Ammon's horn and the dentate gyrus did not differ significantly between young and old rats. The pattern of the LCGU reduction found in the old rats roughly resembles changes found after fimbra-fornix lesions or systemic administration of scopolamine, suggesting a functionally important deficit in the cholinergic innervation of the old rats' hippocampi.     

Parvalbumin-immunoreactive structures in the hippocampus of the human adult

Summary Parvalbumin-immunoreactive structures in the fascia dentata and Ammon's horn of the adult human brain were studied using the avidin-biotin-peroxidase technique. Thin fibres (probably axons) were found to form dense networks throughout the cellular layers. Parvalbumin immunoreactivity is observed in even distal portions of nerve cell processes. The excellent quality of the immunoreaction renders the distinction of a large number of possible neuronal types. All parvalbumin-immunoreactive neurons belong to the class of non-granule cells in the fascia dentata and non-pyramidal neurons in Ammon's horn. The fascia dentata harbours four types of neurons in the molecular layer, one type within the granule cell layer and four types in the plexi-form layer. The frequently described basket cells are contained in the group of immunoreactive non-granule cells in the plexiform layer. In field CA4 two neuronal types can be distinguished. Field CA3 reveals a slender cell type in the stratum radiatum, three types in the pyramidal cell layer and three types in the stratum oriens. In field CA2 three neuronal types can be differentiated in the stratum pyramidale. The extended field CA1 is endowed with two types of nerve cells within the stratum moleculare, two types in the stratum radiatum, five neuronal types in the stratum pyramidale, and one spindle-shaped type in the stratum oriens. The morphological features of parvalbumin-immunoreactive neuronal types in the adult human brain are compared with those found in Golgi-studies of mostly young animals or in labelling experiments. This study serves as a basis for further analyzes involving specific diseases such as Alzheimer's disease or epilepsy, where it needs to be clarified to which extent certain neuronal types are afflicted.