促红细胞生成素对大鼠脑缺血海马CA1区神经元凋亡和细胞色素C释放的影响

目的　探讨促红细胞生成素 (Erythropoietin ,EPO)的神经保护机制。方法　采用 4 VO法制作大鼠全脑缺血模型。将SD大鼠随机分为假手术组、生理盐水组、EPO组。全脑缺血前 3h ,EPO组大鼠脑室立体定向注射重组人促红细胞生成素 (recombinantHumanErythropoietin ,rHuEPO) ,生理盐水组则给予生理盐水 ,假手术组只进行假手术处理。观察缺血后 2 4h海马CA1区细胞色素C(CytochromeC ,CytC)的变化 ,及缺血后 72h海马CA1区细胞凋亡情况。结果　EPO组海马CA1区呈现点状分布的CytC表达较生理盐水组增强 (P <0 .0 1) ,并且较生理盐水组呈现较少的凋亡细胞 (P <0 .0 1)。结论　EPO预处理可以抑制海马CA1区CytC从线粒体向胞浆释放及减少神经元凋亡。     

酸敏感离子通道2a对缺血预处理诱导大鼠海马缺血耐受的作用

目的探讨脑缺血时的组织病理学变化及酸敏感离子通道2a（ASIC2a）在缺血预处理诱导的脑缺血模型耐受中的作用。方法取成年雄性SD大鼠160只,随机分为假手术组、预缺血组、缺血组、缺血预处理组共4组。行焦油紫染色观察各组大鼠海马CAI区存活神经元密度,TUNEL染色观察大鼠海马CA1区神经元凋亡情况,RT—PCR和Western blotting检测ASIC2a在大鼠海马CAl区mRNA和蛋白表达情况。结果缺血预处理能够显著减少大鼠海马CA1区锥体神经元的死亡和凋亡,PC＋Isch组和Isch组相比具有显著性差异（P〈0．01）。全脑缺血能够上调ASIC2a在大鼠海马CA1区mRNA和蛋白表达,在24h达到高峰,而缺血预处理进一步上调ASIC2a表达,呈进行性上升,在24h和72h时相点,PC＋Isch组和Isch组相比具有显著性差异（P〈0．01）。结论在脑缺血耐受中,缺血预处理对第二次致死性缺血表现出保护作用。在这个过程中,大鼠海马CA1区ASIC2a基因和蛋白表达上调发挥了重要的保护作用。     

缺血后处理对脑缺血大鼠学习记忆能力的影响

目的研究缺血后处理(IP)对大鼠脑缺血再灌注损伤后的学习和记忆能力的影响,探讨各组大鼠脑缺血再灌注后海马CA1区β淀粉样蛋白前体(APP)表达。方法将48只雄性SD大鼠随机分为3组:假手术组、对照组和缺血后处理组(IP组),每组16只大鼠。术后用Morris水迷宫方法测定大鼠认知记忆能力变化。3组大鼠脑组织切片行HE染色和APP染色,并行统计学分析。结果 Morris水迷宫试验显示,对照组大鼠训练第1~4天逃避潜伏期长于IP组(P 0. 01);跨越原平台次数IP组明显多于对照组(P 0. 05)。HE染色结果显示,对照组大鼠海马CA1区神经元细胞脱失明显,而IP可减轻这种形态学改变。免疫组化结果显示,在脑缺血再灌注144 h后对照组中APP表达明显高于假手术组(P 0. 01); IP组海马CA1区APP表达较对照组减少(P 0. 05)。结论缺血后处理可通过抑制APP的表达改善缺血再灌注后大鼠的记忆减退。     

慢性应激对大鼠海马CA3区锥体细胞形态结构的效应

目的　探讨慢性应激对大鼠海马CA3区锥体细胞形态结构的效应。方法　将 2 6只雄性Sprague Dawley大鼠随机分为对照组和应激组 ,每组 13只。采用尼氏 (Nissl)染色法、高尔基 (Golgi)镀染法和透射电镜技术 ,观察慢性强迫游泳应激对大鼠海马CA3区锥体细胞形态结构的效应。结果应激组大鼠海马CA3区锥体细胞数 (35 1± 3 9)较对照组 (38 7± 3 5 )明显减少 (P <0 0 5 ) ;顶树突的总长度为 (15 5 7± 33 3) μm ,较对照组 (195 6± 34 6 ) μm明显缩短 (P <0 0 5 )。应激组大鼠海马CA3区锥体细胞出现超微结构的改变 ,包括细胞固缩、体积缩小、核膜皱缩、线粒体变性和粗面内质网模糊不清。结论　慢性应激可引起海马CA3区锥体细胞形态和微细结构的改变及细胞丧失。     

西洛他唑对全脑缺血大鼠海马磷酸化蛋白激酶B及半胱氨酸天冬酶-3表达的影响

目的研究西洛他唑对全脑缺血大鼠海马磷酸化蛋白激酶B(p-Akt)及半胱氨酸天冬酶-3(caspase-3)的影响。方法用四血管阻断法制作大鼠全脑缺血再灌注模型。将112只(模型成功率为75(,死亡后补充动物)约300g的健康成年SD大鼠随机分为3组:假手术组(n=16)、缺血模型对照组(n=48)及治疗组(n=48)。治疗组于缺血前6h和2h各灌胃给予1次西洛他唑,以后每隔24h在相应时间点给药,其它各组灌胃给予等量二甲基亚砜。缺血模型对照组和治疗组于缺血10min再灌注0h、1h、12h、24h、72h、7d后断头取脑,免疫组织化学方法分析再灌注后不同时间点海马CA1区p-Akt和再灌注后caspase-3表达水平的变化。结果全脑缺血后0h、1h,治疗组海马CA1区p-Akt平均光密度值明显高于模型组(P<0.01;P<0.05)。缺血后24h、72h、7d,治疗组海马CA1区caspase-3平均阳性细胞数明显低于模型组(P<0.05)。结论西洛他唑可以降低大鼠全脑缺血再灌注后海马CA1区caspase-3表达水平,并可抑制再灌注后p-Akt水平的急剧降低。     

缺血预处理对局灶性脑缺血再灌注大鼠缺血侧海马CA1区低氧诱导因子-1α及存活素表达的影响

目的探讨缺血预处理对局灶性脑缺血再灌注大鼠缺血侧海马CA1区低氧诱导因子-1α(HIF-1α)及存活素表达的影响。方法健康雄性SD大鼠130只随机分为假手术组(SO组,n=10)、局灶性脑缺血再灌注组(MCAO组,n=60)、缺血预处理组(BIP组,n=60),MCAO组和BIP组又分别分为再灌注2 h、6 h、12h、24 h、48 h、72 h 6个亚组,每亚组10只大鼠。采用线栓法制备大鼠脑缺血再灌注模型。BIP组在缺血前24h给予10 min的预缺血。采用免疫组化染色法检测HIF-1α、存活素的阳性细胞数。采用Western blot法检测HIF-1α、存活素的蛋白相对含量。结果与SO组比较,MCAO组和BIP组各时间点亚组大鼠缺血侧海马CA1区HIF-1α及存活素的阳性细胞数及蛋白相对含量均明显升高(均P0.05)。与MCAO组比较,BIP组各时间点亚组大鼠缺血侧海马CA1区HIF-1α及存活素的阳性细胞数及蛋白相对含量均明显升高(均P0.05)。在MCAO组和BIP组中,大鼠缺血侧海马CA1区HIF-1α及存活素的阳性细胞数及蛋白相对含量均在再灌注24 h时达到最高峰(均P0.05)。结论缺血预处理能够诱导局灶性脑缺血再灌注大鼠缺血侧海马CA1区HIF-1α、存活素表达上调,这或许与脑缺血耐受的产生机制有关。     

电针对老年性痴呆大鼠海马神经元突触形态可塑性的影响研究

目的探讨电针治疗老年性痴呆的突触可塑性机制,为老年性痴呆的针灸作用机理研究提供新的思路。方法 SD大鼠随机分为对照组、模型组、假手术组和电针组;以穹隆-海马伞切断进行“老年性痴呆”造模,电针“百会”、“涌泉”、“太溪”、“血海”后,电镜观察海马CA3区突触形态可塑性指标突触数密度(Nv)、突触面密度(Sv)及平均面积(S)的变化。结果模型组大鼠的Nv(2．16± 0．17)、Sv(0．09±0．02)较对照组(6．16±0．96,0．27±0．05)明显减少(P<0．01);电针组大鼠的Nv(5．08±1．02)、Sv (0．23±0．04)较模型组明显增加(P<0．01)。模型组(0．20±0．03)大鼠S较对照组(0．04±0．01)明显增加fP<0．01); 电针组大鼠的S(0．06±0．01)较模型组明显减少(P<0．01)。结论电针“百会”、“涌泉”、“太溪”、“血海”具有一定程度的促进突触可塑性发挥的作用。     

Tat-GluR6-9c抑制MLK3-MKK7-JNK信号通路对脑缺血再灌注大鼠海马CA1区神经元的保护作用

目的 探讨小肽Tat-GluR6-9c对混合性的谱系激酶3(MLK3)、丝裂原活化的蛋白激酶激酶7(MKK7)、c-Jun氨基末端激酶(JNK)的磷酸化水平及蛋白表达的影响,以及对海马CA1区神经元损伤的影响. 方法 采用4-血管阻塞方法建立大鼠全脑缺血模型,应用免疫印迹的方法分别检测小肽Tat-GluR6-9c对缺血再灌注6h时MLK3、缺血再灌注3d时JNK的磷酸化及蛋白表达水平的影响;采用免疫印迹、免疫组织化学的方法检测小肽Tat-GluR6-9c对缺血再灌注1d时MKK7的磷酸化及蛋白表达水平的影响;采用焦油紫染色方法检测缺血再灌注5d时小肽Tat-GluR6-9c对大鼠海马CA1区神经元损伤的影响. 结果 Tat-GluR6-9c组MLK3、MKK7及JNK磷酸化水平显著低于缺血再灌注组及对照肽组,海马CA1区神经元存活的数量明显多于缺血再灌注组及对照肽组,差异有统计学意义(P＜0.05). 结论 小肽Tat-GluR6-9c能显著抑制脑缺血再灌注诱导的MLK3、MKK7及JNK的磷酸化高峰,降低海马CA1区神经元的损伤.     

挤压伤至股骨干骨折对大鼠海马CA1区形态学变化

目的观察挤压伤(CS)至股骨干骨折后缺血/再灌注(I/R)引起的SD大鼠海马CA1区形态学的变化特征。方法建立大鼠CS模型,SD大鼠双侧后肢挤压6 h,再灌注0、6、12、24 h,4%多聚甲醛灌注,用刀片把脑组织从正中矢状位分为左右两半,自上丘至视交叉节段取脑组织,一半用于高尔基染色,一半制备成石蜡切片,分别用于HE染色和Nissl染色。结果挤压伤至股骨干骨折I/R后开始出现大鼠海马神经元疏松紊乱、肿胀变性,形态结构受损,凋亡数目增加,神经元大量丢失,海马CA1区树突棘密度减少,挤压再灌注12 h最为显著,24 h上述形态有所改善,但仍低于正常水平。结论 I/R引起SD大鼠海马CA1区神经元细胞受损,受损程度在解压后12 h达到高峰。     

全脑缺血-再灌注对海马CA1区GAD65表达的影响及意义

目的探讨全脑缺血-再灌注对成年大鼠海马CA1区GAD65表达的影响及意义。方法成年雄性SD大鼠24只,随机分为3组:假手术组(SH)、缺血-再灌注3d组(IR-3)及缺血-再灌注7d组(IR-7),每组8只。采用四动脉阻断法制作全脑缺血-再灌注模型,应用免疫组织化学方法检测海马CA1区谷氨酸脱羧酶(glutamic acid decarboxylase,GAD)同工酶GAD65的表达变化。结果与假手术组相比,IR-3组GAD65的表达明显增多,IR-7组恢复正常。结论GABA能中间神经元对缺血相对耐受;全脑缺血-再灌注3dGAD65的表达增多可能是一种代偿性的机制,以减轻脑缺血后的高兴奋性。     

脑血管病与血脂的关系

目的 探讨脑血管病(CVD)与血脂的关系。方法 检测53例脑出血(CH)及60例脑梗死(CI)患者的血脂,并与60名同龄健康对照组比较。结果 CH组TC、HKL一C、LDL-C高于对照组;TG低于对照组,但均无显著性差异(P>0.05)。CI组HDL-C显著低于对照组和CH组(P<0.005);TC、TG、LDL-C高于对照组,但无显著性差异(P>0.05〕;TG明显高于CH组(P<0.05)。结论 HDL-C是CI的保护因素,CH和CI与血脂的关系不同,甚至完全相反,他们有着不同的发病机制。     

基础血压对低血压诱发脑梗塞的影响

目的探讨大鼠的基础血压和脑血管的病理改变对低血压诱发脑梗塞的影响。方法将易卒中型肾血管性高血压大鼠（RHRSP）和正常血压SD大鼠各72只急速降压后，观察脑组织的病理改变。结果SD大鼠无脑梗塞发生；38只发生脑梗塞的RHRSP中，32只的基础血压显著高于无脑梗塞的RHRSP的基础血压（P＜0．05），且脑内小动脉硬化改变也较严重，另6只有脑梗塞的RHRSP（血压均降至8kPa）的基础血压及脑内小动脉硬化改变与无梗塞的RHRSP的相似。结论高血压的严重程度和持续时间是低血压诱发脑梗塞的重要因素。     

黄芪对大鼠脑缺血血脑屏障及脑血流的影响

利用大鼠局灶性脑缺血再灌流和全脑缺血再灌流损伤两种动物模型，观察黄芪注射液对脑缺血后再灌注期间血脑屏蔽及脑血流的保护作用。结果显示，与相庆对照组比较，不论是全脑缺血还是局灶性脑缺血１ｈ后再灌流３ｄ，应用黄芪的各组动物脑水肿明显减轻，血脑屏障通透性改善，大脑局部血流量显著增加。     

Influence of nimodipine on cerebral blood flow in human cerebral ischaemia

Summary Cerebral blood flow (CBF) was measured by xenon-133 inhalation and single photon emission computerized tomography (SPECT) in 7 patients with acute cerebral ischaemia prior to and 30 min after intravenous infusion of nimodipine (1 mg). Neurological examination, CT and CBF study were performed no later than 6 h after the onset of symptoms. Regional perfusion abnormalities were seen in all patients when the CT scan was still normal. Follow-up CT revealed low-density areas roughly corresponding to the core of the perfusion defect. Nimodipine infusion significantly decreased the mean arterial blood pressure (P<0.01), while PaCO₂ and clinical symptoms remained unchanged. A significant CBF improvement (P<0.05) after nimodipine was seen in the border zone of the ischaemic infarct but not in the core of the lesion or in the unaffected contralateral hemisphere.     

Endorphinergic mechanisms in cerebral blood flow autoregulation

The influence of naturally occurring opioid peptides (Met-enkephalin (Met-Enk), dynorphin (DYN), β-endorphin (β-EP)) as well as morphine and the opiate antagonist naloxone and specific antisera on cerebral blood flow autoregulation was studied in anesthetized, artificially ventillated rats. Local hypothalamic blood flow (CBF, H₂-gas clearance technique) and total cerebral blood volume (CBV, photoelectric method) were simultaneously recorded. Autoregulation was tested by determining CBF and CBV during consecutive stepwise lowering of the systemic mean arterial pressure to 80, 60 and 40 mm Hg, by hemorrhage. Resting CBF decreased following Met-Enk, DYN, β-EP or morphine administration without simultaneous changes in CBV. Naloxone administration, on the contrary, increased CBV without affecting local CBF. Autoregulation of cerebral blood flow was maintained until 80 mm Hg, but not completely at 60 and 40 mm Hg arterial pressure in the control group. General opiate receptor blockade by 1 mg/kg s.c. naloxone abolished autoregulation at all levels, since CBF and CBV passively followed the arterial pressure changes. Intracerebroventricularly injected naloxone (1 μg/kg) as well as a specific antiserum against β-EP, but not against Met-Enk or DYN, resulted in the very same effect as peripherally injected naloxone. The present findings suggest that central, periventricular β-endorphinergic mechanisms might play a major role in CBF autoregulation.     

脑出血患者脑血流速度的观察

目的 观察脑出血后脑主要动脉的血流速度变化,进而研究脑血流动力学变化的临床价值。方法 采用经颅超声多普勒(transcranial Doppler,TCD)分别对216例脑出血患者和80名健康对照者的大脑中动脉、大脑前动脉、大脑后动脉、颈内动脉、基底动脉和椎动脉等颅内主要动脉的血流速度进行检测分析,记录包括收缩期峰速(Vs)、舒张期末流速(Vd)及搏动指数(PI)等血流参数及频谱形态。结果 脑出血组患者收缩期峰速与舒张末期流速与对照组比较均降低,差异有显著性意义(P<0.001)。脑出血组有164例患者(7.93％)颅内动脉血流速度降低,其中51例(23.61％)发生于脑出血早期,以舒张期末流速降低为主,113例(52.31％)发生于脑出血的中、后期,表现为普遍性流速降低。另有52例(24.07％)脑血流速度基本正常。结论 多数脑出血患者脑组织处于低循环状态,其程度与病情相关,因此对脑出血患者进行血流动力学监测有助于指导治疗及判断预后。     

脑血管病患者血脂水平改变的临床意义

目的 :探讨脑血管病患者血脂变化规律。方法 :脑梗死患者 10 6例、脑出血患者 6 5例和非脑血管病患者 83例 ;脑梗死组又分为初发和复发、<6 0和≥ 6 0岁、以及合并高血压、糖尿病和冠心病等亚组。用比色法测定甘油三酯 (TG)、高密度脂蛋白胆固醇 (HDL -C)、总胆固醇 (TC)和低密度脂蛋白胆固醇 (LDL -C)水平。结果 :脑梗死组血清TC、TG和LDL -C水平明显高于对照组 ,而HDL -C水平与对照组无明显差异。老年脑梗死组TC、TG水平显著高于对照组 ;复发脑梗死组TC、LDL -C水平显著高于对照组 ;脑出血患者血脂指标和对照组相比无显著差异 ;合并高血压和糖尿病组血清TC、TG和LDL -C均高于单纯脑梗死组和对照组。结论 :血清TC、LDL -C主要与复发性脑梗死有关 ,而TC、TG主要与老年脑梗死发生有关 ;血清TC、TG和LDL -C升高与脑梗死合并高血压和糖尿病有关     

Influence of blood viscosity to cerebral blood flow in older humans compared to young subjects

Objective

Since blood viscosity (BV) is one of the most important factors determining blood flow, this study aimed to investigate the possible correlation between increased blood viscosity and reduction of regional cerebral blood flow (rCBF) in healthy ageing.

Methods

Male subjects were distributed in two groups: “young”, aged 20-30 (27 volunteers), or “elderly”, aged 60-70 (50 volunteers). Whole blood viscosity was obtained with a Wells-Brookfield Cone/Plate Viscometer. Cerebral blood flow was analysed by means of single photon emission computed tomography (SPECT).

Results

The mean BV values were 3.28 ± 0.43 mPa in the group of young volunteers and 4.33 ± 0.73 mPa in the group of elderly volunteers (t = −6.9, p < 0.0001). The elderly had a lower blood flow than the young in the following regions: bilateral parietal; temporal-parietal and temporal of the left hemisphere. Pearson’s correlation between BV and rCBF showed a good inverse correlation when the BV was above 3.95 ± 0.83 mPa.

Conclusions

Our results point to a close relationship between the two parameters analysed, BV and rCBF. The impairment in rCBF observed in the elderly volunteers might be due to an increase in BV, among other factors.

Significance

These findings suggest interesting possibilities for the treatment/prevention of brain ageing.     

Cerebral blood flow-metabolism coupling after administration of soman at nontoxic levels

The effect of soman, an irreversible organophosphorus cholinesterase inhibitor, on regional cerebral blood flow and glucose utilization were studied with a double-tracer, autoradiographic technique in rats. Soman was given at a subtoxic dose of 55 micrograms/kg SC and variables were measured 45 min later. No changes in arterial blood pressure or signs of toxicity were present in the animals studied. Soman induced a pronounced increase in cerebral blood flow. This change was not accompanied by an increase in cerebral metabolism, with exception of superior colliculi. Brain regions showing the more pronounced (greater than 200% over control) increases in blood flow were motor, sensory and temporal cortex, area 18a of the occipital cortex, claustrum, inferior colliculus and cerebellum. These findings differ from those previously reported for the carbamate cholinesterase inhibitor, physostigmine, and constitute the first demonstration of cerebrovascular effects for an organophosphorus cholinesterase inhibitor, soman, at nonsymptomatic doses.     

Caffeine-induced cerebral blood flow changes in schizophrenia

Summary Cerebral blood flow (CBF) measurements and mental status examinations were performed before and 30 min after oral administration of 250 mg of caffeine or a placebo given under double-blind conditions, in two groups of patients with schizophrenia. Caffeine produced significant CBF reductions but no changes in the patient's clinical condition.