血管性痴呆小鼠海马胆碱乙酰转移酶mRNA表达特征研究

目的探讨血管性痴呆小鼠海马神经元胆碱乙酰转移酶原位杂交变化特征及其在血管性痴呆发病中的作用。方法双侧颈总动脉线结反复缺血-再灌注法制备模型,利用跳台试验和水迷宫试验观测其行为学改变,采用原位杂交技术观测小鼠海马神经元胆碱乙酰转移酶mRNA的表达变化。结果模型组小鼠学习、记忆成绩较假手术明显降低(P<0.01),其海马胆碱乙酰转移酶mRNA表达也明显下降(P<0.01)。结论血管性痴呆小鼠学习、记忆成绩下降可能与其海马胆碱乙酰转移酶mRNA低水平表达有关。     

血管性痴呆小鼠海马胆碱乙酰转移酶mRNA表达特征及石杉碱甲的影响

目的观测石杉碱甲对血管性痴呆小鼠海马神经元胆碱乙酰转移酶(ChAT)原位杂交的影响,进一步研究其在血管性痴呆发病中的作用及石杉碱甲对其影响的机制。方法双侧颈总动脉线结,反复缺血-再灌注法制备模型,药物组用石杉碱甲溶液灌胃,跳台试验和水迷宫试验观测其行为学改变,采用原位杂交技术观测小鼠海马神经元ChAT mRNA的表达变化。结果石杉碱甲组小鼠学习、记忆成绩优于模型组(P<0.01),其海马ChATmRNA表达也明显增高(P<0.01)。结论石杉碱甲改善血管性痴呆小鼠学习、记忆成绩与其恢复海马低水平的ChAT mRNA有关。     

胰岛素样生长因子-1在血管性痴呆中的作用

血管性痴呆(VD)是痴呆的常见类型,是脑血管疾病造成的脑部损伤所致的智力损害综合征。胰岛素样生长因子-1(IGF-1)属于胰岛素家族,脑内IGF-1通过与其受体结合发挥促进神经元分化的作用。在脑缺血性损伤后,脑组织中IGF-1及其受体表达增加,能减少梗死面积,修复损伤的神经元。血管性痴呆患者组织病理学上有胆碱能活性降低,IGF-1是脑内胆碱能系统潜在调节因子。     

胰岛素样生长因子-1对痴呆模型大鼠学习记忆能力影响及其可能机制

目的 探讨胰岛素样生长因子-1(IGF-1)对痴呆模型大鼠学习记忆能力的影响及其可能机制.方法 本研究采用切断成年Wistar大鼠双侧穹窿海马伞,建立隔-海马胆碱能系统损害的痴呆模型.分为正常对照组、假手术组、痴呆组、小剂量IGF-1组、大剂量IGF-1组.痴呆模型制备1d后开始侧脑室给药,连续21d.正常对照组不给予任何处置.利用水迷宫观察其行为学改变,利用原位杂交、免疫组化及图像分析测定大鼠脑内胆碱乙酰转移酶(ChAT)和突触素的表达.结果 痴呆组与正常对照组相比,其学习记忆能力明显下降,脑内chAT及突触素的表达量明显减少(P＜0.001),小剂量IGF-1组、大剂量IGF-1组大鼠的学习记忆成绩优于痴呆组(P＜0.01),其脑内ChAT.及突触索的表达量与痴呆组相比也明显增多(P＜0.001),且小剂量IGF-1组优于大剂量IGF-1组(P＜0.01).结论 IGF-1能改善痴呆模型大鼠的学习记忆能力,脑内ChAT及突触索的表达量增加是其可能机制.     

雌激素对血管性痴呆大鼠学习记忆功能及海马IGF-1表达的影响

目的探讨雌激素对血管性痴呆大鼠学习记忆功能及海马CA1区胰岛素样生长因子-1(IGF-1)表达的影响。方法 30只雄性SD大鼠随机分为假手术组、模型组和雌激素组,每组10只。采用双侧颈总动脉结扎法制备VD大鼠模型;雌激素组腹腔注射17-β雌二醇(花生油溶解)1mg/kg,同时假手术组和模型组腹腔注射等量的花生油,均为隔日1次,共30次。60d后,用Morris水迷宫测定各组大鼠进行学习和记忆功能,HE染色观察大脑海马CA1区神经细胞形态学变化,免疫组化染色检测其IGF-1阳性神经细胞数目的表达。结果假手术组海马CA1区未见明显的病理变化,模型组细胞数和神经元层次明显减少,雌激素组偶见小的软化灶,细胞数和形态接近假手术组组;与假手术组相比,模型组及雌激素组认知能力明显下降,海马CA1区IGF-1表达增加(P均0.05);与模型组比较,雌激素组认知能力改善,海马CA1区IGF-1表达明显增加(P均0.05)。结论 17-β雌二醇对VD大鼠脑组织损伤及学习记忆功能减退有明显的改善作用,这可能与增加大鼠海马IGF-1的含量有关。     

血管性痴呆小鼠海马胆碱乙酰转移酶mRNA变化特征及喜得镇的影响

目的:观测喜得镇对血管性痴呆小鼠海马神经元胆碱乙酰转移酶mRNA变化的影响,以探讨胆碱乙酰转移酶mRNA变化在血管性痴呆发病中的作用及喜得镇对此变化的机制。方法:双侧颈总动脉线结.反复缺血-再灌注法制备模型,药物组用喜得镇溶液灌胃,利用跳台试验和水迷宫试验观测其行为学改变,采用原位杂交技术观测小鼠海马神经元胆碱乙酰转移酶mRNA的表达变化。结果:喜得镇组小鼠学习、记忆成绩优于模型组(P<0.01),其海马胆碱乙酰转移酶mRNA表达也明显增高(P<0.01)。结论:喜得镇改善血管性痴呆小鼠学习、记忆成绩与其恢复海马低水平的胆碱乙酰转移酶mRNA有关。     

苯甲酸雌二醇对慢性脑缺血大鼠海马胆碱乙酰转移酶变化及雌激素的影响

目的观察苯甲酸雌二醇对慢性脑缺血大鼠海马神经元胆碱乙酰转移酶的影响,以探讨胆碱乙酰转移酶的变化在慢性脑缺血发病中的作用及雌二醇对此变化的影响。方法采用双侧颈总动脉永久性结扎制备慢性脑缺血模型,30只大鼠随机分为假手术组、缺血组和雌二醇治疗组。各组于造模60d后,应用Y迷宫观察其行为学改变,采用免疫组化观测大鼠海马神经元胆碱乙酰转移酶的变化。结果治疗组较缺血组认知障碍明显改善（P〈0.01）,其海马胆碱乙酰转移酶的表达也明显增高（P〈0.01）。结论苯甲酸雌二醇能改善慢性脑缺血大鼠的认知功能可能与其提高海马区胆碱乙酰转移酶水平有关。     

雌激素对血管性痴呆大鼠认知功能、海马Bcl-2、Bax蛋白表达及神经元凋亡的影响

目的 探讨雌激素对血管性痴呆(VD)大鼠认知功能、海马Bcl-2、Bax蛋白表达和神经元凋亡的影响.方法 60只雄性大鼠随机分为假手术组、VD组和雌激素组,每组20只.采用双侧颈总动脉结扎法制备VD大鼠模型;雌激素组腹腔注射17-β雌二醇(花生油溶解)200 μg/kg,同时假手术组和VD组腹腔注射等量的花生油,均为隔日1次,共30次.60 d后,Y-型迷宫试验检测大鼠学习记忆能力;HE染色观察大鼠海马神经元形态;免疫组化染色检测海马Bcl-2、Bax蛋白的表达,原位缺口末断标记(TUNEL)法检测神经元凋亡程度.结果 与假手术组相比,VD组及雌激素组认知能力明显下降, 海马CA1区Bcl-2、Bax蛋白表达增加,TUNEL 阳性细胞数明显增多(均P<0.001);与VD组比较,雌激素组认知能力改善,海马CA1区Bcl-2蛋白表达明显增加,Bax蛋白的表达明显减少,TUNEL 阳性细胞明显减少 (均P<0.001).结论 17-β雌二醇可调节Bcl-2、Bax蛋白表达而抑制神经元凋亡,有助于改善VD大鼠的认知能力.     

雌二醇对血管性痴呆大鼠海马CA1区GFAP表达的影响

目的研究17β-雌二醇对血管性痴呆（vascular dementia，VD）大鼠海马CA1区GFAP表达的影响，探讨雌激素对血管性痴呆大鼠中枢神经系统保护作用的机制。方法采用结扎双侧颈总动脉方法制备血管性痴呆动物模型，腹腔注射不同剂量17β-雌二醇60d后，应用γ迷宫检测各组VD大鼠认知功能以及免疫组化法等检测大鼠大脑海马CA1区GFAP表达的变化。结果腹腔注射17β-雌二醇60d后，大鼠认知功能显著改善；学习、记忆功能测试30次的正确次数较实验对照组明显增高（P〈0．05），造模60d后的大鼠，其脑内CA1区GFAP免疫阳性细胞数较假手术组显著增高，而雌二醇组大鼠CA1区GFAP免疫阳性细胞数较实验对照组显著减少。结论雌激素补充疗法能选择性影响血管性痴呆大鼠脑内CA1区GFAP阳性细胞，并有可能影响学习和记忆能力。     

天智颗粒对血管性痴呆大鼠行为学及脑内AchE、ChAT活性的影响

目的观察天智颗粒对血管性痴呆大鼠行为学习记忆能力和乙酰胆碱代谢酶活性的影响,从而探讨天智颗粒改善记忆的机制.方法采用双侧颈总动脉结扎法建立血管性痴呆模型,治疗组用天智颗粒(5 g/kg)灌胃,模型组和假手术组用同体积的蒸馏水代替灌胃,1次/天,对照组未做任何处理.30 d后,采用三等分Y型电迷宫和比色法分别测定皮质、海马区乙酰胆碱脂酶(AchE)活性和基底前脑区胆碱乙酰转移酶(ChaT)活性.观察、比较各组大鼠行为学和乙酰胆碱代谢酶的变化规律和差异.结果治疗30d后,治疗组与模型组相比,学习记忆能力和基底前脑ChaT活性明显提高(P＜0.05),但皮质和海马区AchE活性变化无统计学意义.结论天智颗粒能明显促进血管性痴呆大鼠学习记忆能力和基底前脑区ChaT活性,其药理机制可能和改变乙酰胆碱代谢酶活性有关.     

Puerarin decreases hypoxia inducible factor-1 alpha in the hippocampus of vascular dementia rats

In this study, a rat vascular dementia model was established by permanent bilateral common carotid arterial occlusion. Rats were intraperitoneally injected with puerarin 3 days before modeling, for 45 successive days. Results demonstrated that in treated animals hippocampal structures were clear, nerve cells arranged neatly, and cytoplasm was rich in Nissl bodies. The number of cells positive for hypoxia inducible factor-1 alpha, erythropoietin and endothelial nitric oxide synthase was reduced; and the learning and memory abilities of rats were significantly improved. Our experimental findings indicate that puerarin can significantly improve learning and memory in a vascular dementia model, and that the underlying mechanism may be associated with the regulation of the expression of hypoxia inducible factor-1 alpha.     

A comparison of brain choline acetyltransferase activity in Alzheimer's disease,multi-infarct dementia,and combined dementia

Summary Brain choline acetyltransferase (ChAT) activity was determined in 43 patients with Alzheimer's disease (AD), 14 with multi-infarct dementia (MID), and 15 with combined dementia (CD) and in 53 age-matched controls. The activity of ChAT declined in the hippocampus, temporal and frontal cortex in patients with AD and CD compared to the controls. In the AD group the reduced activity of ChAT in all brain areas was associated with a greater number of cortical neurofibrillary tangles. The degree of dementia had a negative correlation with the activity of ChAT in the frontal cortex in both AD and CD patients. The activity of ChAT in the temporal cortex of CD patients was negatively associated with the cortical tangle counts. In contrast, the activity of ChAT and MID patients was not essentially different from that of the controls. Neither did the various clinical and neuropathological variables show any significant correlation with ChAT activity in MID patients. Thus, in this study the reduction in the activity of ChAT seems to be associated with Alzheimer-type pathology but not with dementia due to vascular changes.     

Acetylcholine-rich transplants in the hippocampus: influence of intrinsic growth factors and application of nerve growth factor on choline acetyltransferase activity

Three groups of rats received either unilateral fimbria-fornix lesions by aspiration through the overlying cingulate cortex (group I), a fimbria-fornix lesion followed by an intrahippocampal transplant of acetylcholine (ACh)-rich embryonic septal tissue (group II), or a similar septal transplant placed into the intact hippocampus, in the absence of the denervating lesion (group III). The 3 groups were subdivided into equal subgroups receiving 6 intrahippocampal injections of nerve growth factor (NGF) at 4-day intervals, control injections of cytochrome c, or no injections. On the 28th day all animals were sacrificed and the majority taken for biochemical analysis of hippocampal choline acetyltransferase (ChAT). The animals with intact hippocampi (group III) were given a denervating fimbria-fornix lesion 3 days prior to sacrifice in order to reveal graft-derived ChAT activity from intrinsic ChAT activity. The fimbria-fornix lesions (group I) depleted hippocampal ChAT activity to 15-20% of normal, which was not influenced by NGF injections. The ACh-rich grafts placed in the denervated hippocampus (group II) restored hippocampal ChAT activity to approximately 60% of the normal level, and this was promoted to approximately 84% of NGF, but not cytochrome c, injections into the hippocampus. Grafts placed into the intact hippocampus (group III) did not raise ChAT activity above the lesion-alone level, and this was not influenced by NGF injections. Acetylcholinesterase (AChE) histochemistry showed no difference in outgrowth from the grafts in the denervated hippocampus with or without NGF injections. The results are interpreted, in agreement with observations in tissue culture, as indicating that NGF enhances ChAT activity in grafted neurons, rather than promoting survival and growth per se.     

胰岛素样生长因子-1对痴呆模型大鼠额叶、海马Caspase-3P20活性片段及Bcl-2蛋白表达的影响

目的 探讨胰岛素样生长因子-1(IGF-1)对痴呆模型大鼠额叶、海马caspase-3 P20活性片段及Bcl-2蛋白表达的影响.方法 本研究采用切断成年Wistar大鼠双侧穹隆海马伞,建立隔-海马胆碱能系统损害的痴呆模型.分为正常对照组、假手术组、痴呆组、小剂量胰岛素样生长因子-1(IGF-1)组、大剂量IGF-1组.痴呆模型制备1d后开始侧脑室给药,连续21d.正常对照组不给予任何处置.利用免疫组织化学染色结合图像分析方法观察各组大鼠额叶、海马胆碱能神经元caspase-3 P20活性片段、Bcl-2蛋白的表达,并进行光密度值(IOD)测定.结果 小剂量IGF-1组和大剂量IGF-l组与痴呆组相比,caspase-3 P20阳性神经元IOD值明显降低,具有显著差异(P＜0.001).小剂量IGF-1组与大剂量IGF-1组比较,caspase-3 P20阳性神经元IOD值明显降低,具有显著性差异(P＜0.05或P＜0.01).小剂量IGF-1组和大剂量ICF-1组与痴呆组相比,额叶、海马Bcl-2阳性神经元明显增多,IOD值明显增加,具有显著差异(P＜0.001).小剂量IGF-1组与大剂量IGF-1组比较,Bcl-2阳性细胞增多,IOD值明显增高,差异显著(P＜0.05或P＜0.01).结论 ICF-1能够通过抑制caspase-3的活化并增加Bcl-2的表达量,减少细胞凋亡.     

Effects of trimethyltin (TMT) on choline acetyltransferase activity in the rat hippocampus

Trimethyltin (TMT) destroys specific subfields of the hippocampus in the rat. TMT also increases choline acetyltransferase (ChAT) activity in CA1 of Ammon’s horn and the outer molecular layer of the dentate gyrus. This observation suggests that axonal sprouting occurs in the cholinergic septohippocampal system in response to TMT. However, neither does-response nor time course data are available for the effects of TMT on this enzyme. The effects of three dose levels of TMT on ChAT activity in CA1 and the dentate gyrus were determined in Experiment 1 and ChAT activity in these two areas was measured at six time points following exposure to TMT in Experiment 2. Only the highest dose of TMT (6 mg/kg) significantly increased ChAT activity. ChAT activity in the dentate gyrus increased significantly by 3 d after administration and continued to increase until 21 d after exposure. A significant increase was not observed in CA1 until 7 d after exposure to TMT. Asymptotic levels were still reached at d 21. These results indicate a steep dose-response curve for TMT-induced changes in ChAT activity in the hippocampal formation and that this marker of cholinergic activity is more sensitive to perturbation by TMT in the dentate gyrus than Ammon’s horn.     

Effects of electro-acupuncture on Noxa and caspase-3 expression in hippocampal CA1 region of a vascular dementia rat model

BACKGROUND:Noxa, a pro-apoptotic member of the Bcl-2 protein family, has been shown to induce the mitochondrial pathway of apoptosis and to mediate hypoxic cell death in a rat model of cerebral ischemia. This suggests that Noxa could participate in apoptosis during vascular dementia (VD). OBJECTIVE: To detect Noxa and caspase-3 expression after electro-acupuncture in VD rats to further validate the mechanism of electro-acupuncture-induced effects in the treatment of VD. DESIGN, TIME AND SETTING: A randomize...     

Effects of electro-acupuncture on Noxa and caspase-3 expression in hippocampal CA1 region of a vascular dementia rat model*★

BACKGROUND：Noxa, a pro-apoptotic member of the Bcl-2 protein family, has been shown to induce the mitochondrial pathway of apoptosis and to mediate hypoxic cell death in a rat model of cerebral ischemia. This suggests that Noxa could participate in apoptosis during vascular dementia （VD）. OBJECTIVE： To detect Noxa and caspase-3 expression after electro-acupuncture in VD rats to further validate the mechanism of electro-acupuncture-induced effects in the treatment of VD. DESIGN, TIME AND SETTING： A randomized, controlled study was performed at the Center for the Neurobiology of Fujian Medical University between January 2006 and March 2007. MATERIALS： A total of forty adult, male, Sprague Dawley rats were included in this study. The following equipment was used： confocal laser scanning microscope （Sp5, Leica, Germany）, water maze （Bejing Suntendy Science and Technology Co., Ltd., China）, and SDZ-II electronic acupuncture treatment instruments （Suzhou Medical Appliance Factory, China）. METHODS： Thirty-eight rats with sufficient learning and memory abilities were selected by Morris water maze criteria. Twelve rats received sham-surgery; the remaining 26 rats were used to establish a VD model by bilateral occlusion of the common carotid arteries. The rats that survived the occlusion procedure were randomly assigned into an electro-acupuncture group （n = 11） and a VD model group （n = 12）. MAIN OUTCOME MEASURES： Neuropathological changes were observed with hematoxylin-eosin staining of the hippocampus and expression of Noxa and caspase-3 in the hippocampal CA1 region was analyzed by confocal laser scanning microscope following immunofluorescence staining. RESULTS： Expressions of Noxa and caspase-3 in the electro-acupuncture group and sham-operated group were less than in the VD model group （P 〈 0.01）. Electro-acupuncture reduced the amount of apoptotic neurons in hippocampal CA1 area of rats with VD. The average latency in the Morris water maze test was significantly shorter