Thioredoxin and impaired spatial learning and memory in the rats exposed to intermittent hypoxia

Background  Obstructive sleep apnea (OSA) can cause cognitive dysfunction and may be a reversible cause of cognitive loss in patients with Alzheimer’s disease (AD). Chronic exposure to intermittent hypoxia (IH), such as encountered in OSA, is marked by neurodegenerative changes in rat brain. We investigated the change of thioredoxin (Trx), spatial learning and memory in rats exposed to chronic intermittent hypoxia (CIH).

Methods  Forty healthy male Sprague-Dawley (SD) rats were randomly divided into four groups of ten each: a CIH+normal saline (CIH+NS group), a N-acetylcystein-treated CIH (CIH+NAC) group, a sham CIH group (sham CIH+NS), and a sham NAC-treated sham CIH (CIH+NAC) group. Spatial learning and memory in each group was assessed with the Morris water maze. Real-time PCR and Western blotting were used to examine mRNA and protein expression of Trx in the hippocampus tissue. The terminal deoxynucleotidyl transferase-mediated dUTP-nick end-labeling (TUNEL) method was used to detect the apoptotic cells of the hippocampus CA1 region.

Results  CIH-rats showed impaired spatial learning and memory in the Morris water maze, including longer mean latencies for the target platform, reduced numbers of passes over the previous target platform and a smaller percentage of time spent in the target quadrant. Trx mRNA and protein levels were significantly decreased in the CIH-hippocampus, meanwhile, an elevated apoptotic index revealed apoptosis of hippocampal neurons of rats exposed to CIH. The rats, which acted better in the Morris water maze, showed higher levels of the Trx mRNA and protein in the hippocampus; apoptotic index of the neurons in the hippocampus of each group was negatively correlated with the Trx mRNA and protein levels.

Conclusion  The Trx deficit likely plays an important role in the impaired spatial learning and memory in the rats exposed to CIH and may work through the apoptosis of neurons in the hippocampus.

     

Effect of insulin on the cognizing function and expression of hippocampal Aβ1-40 of rat with Alzheimer disease

Background A model of simulated Alzheimer＇s disease （AD） induced by aggregated amyloid protein （Aβ1-40） was built in Wister rats to observe the behavioral and pathological changes of Aβ1-40 and the effect of hypodermic insulin injected on the function of study and memory and the expression of Aβ1-40 from the CA1 area of the hippocampus. Methods Experimental groups were as follows： contrast, simulated AD model, contrast of Nacl, and insulin treated. The simulated AD model was built by microinjection of aggregated Aβ1-40 at the CA1 area of the hippocampus, and was hypodermically injected with 0.9% NaCI （1 ml/kg） and insulin （0.1 U/kg） separately the next day. Two weeks after the modeling, the four groups were tested with water maze about the study and memory function of rats. Three weeks after the injection, the expression of Aβ1-40 at the CA1 area of the hippocampus was examined by pathological tests （HE, Congo red） and immunohistochemical methods. Results The study and memory abilities of rats were ameliorated significantly by the place navigation test and the spatial probe test after the application of insulin. Insulin could decrease the expression of Aβ1-40 at the CA1 area of the hippocampus to reduce the pathological damage of Aβ1-40 to the hippocampal area of rats. Conclusions The injection of aggregated Aβ1-40 to the hippocampal area could simulate the behavioral and pathological features of AD such as the difficulty of study and memory and the damage to neurons. Insulin is effective to improve the function of study and memory and amend the pathological damage of simulated AD model rats. The results give a experimental proof of insulin in the clinical treatment of AD.     

Protective effects and mechanism of total coptis alkaloids on A β25–35 induced learning and memory dysfunction in rats

Objective: To observe the effect of total coptis alkaloids (TCA) on β-amyloid peptide (Aβ25-35) induced learning and memory dysfunction in rats, and to explore its mechanism. Methods: Forty male Wistar rats were randomly divided into four groups: the control group, the model group, the TCA low dose (60 mg/kg) group and the TCA high dose (120 mg/kg) group, 10 in each. Aβ25-35 (5μl, 2μg/μl) was injected into bilateral hippocampi of each rat to induce learning and memory dysfunction. TCA were administered through intragavage for consecutive 15 days. Morris Water Maze test was used to assess the impairment of learning and memory; concentration of malondialdehyde (MDA) in cerebral cortex was determined by thiobarbituric acid reactive substance to indicate the level of lipid peroxidation in brain tissues; activity of manganese-superoxide dismutase (Mn-SOD) in cerebral cortex was determined by xanthine-oxidase to indicate the activity of the enzyme; and NF-κB protein expression in cerebral cortex was measured by SP immunohistochemistry. Results: (1) Morris Water Maze test showed that, during the 4 consecutive days of acquisition trials, the rats in the model group took longer latency and searching distance than those in the control group (P<0.01), which could be shortened by high dose TCA (P<0.05); during the spatial probe trial on the fifth day, the rats in the model group took shorter searching time and distance on the previous flat area than those in the control group (P<0.01), which could be prolonged after TCA treatment (for low dose group, P<0.05; for high dose group, P<0.01). (2) Analysis of cerebral cortical tissues showed that, compared with the control group, MDA level got significantly increased and Mn-SOD activity decreased in the model group (both P<0.01). After having been treated with TCA, the MDA level got significantly decreased (P<0.05 and P<0.01 respectively for low and high dose group), while relative increase of Mn-SOD activity only appeared in high dose group (P<0.05). (3) Immunohistochemistry analysis showed the protein expression of NF-κB got significantly increased after modeling, while high dose TCA can significantly inhibit it. Conclusion: TCA could improve Aβ25-35 induced dysfunction of learning and memory in rats, and its protective mechanism is associated with its actions in decreasing MDA level, increasing Mn-SOD activity and inhibiting the expression of NF-κB in cerebral cortex.     

DHA Depletion in Rat Brain Is Associated With Impairment on Spatial Learning and Memory

Objective To examine the effect of docosahexaenoic acid （DHA） deficiency in brain on spatial learning and memory in rats. Methods Sprague Dawley rats were fed with an n-3 fatty acid deficient diet for two generations to induce DHA depletion in brain, DHA in seven brain regions was analyzed using the gas-liquid chromatography. Morris water maze （MWM） was employed as an assessing index of spatial learning and memory in the n-3 fatty acid deficient adult rats of second generation. Results Feeding an n-3 deficient diet for two generations depleted DHA differently by 39%-63% in the seven brain regions including cerebellum, medulla, hypothalamus, striatum, hippocampus, cortex and midbrain, The MWM test showed that the n-3 deficient rats took a longer time and swam a longer distance to find the escape platform than the n-3 Adq group. Condusion The spatial learning and memory in adult rats are partially impaired by brain DHA depletion.     

Effects of subconvulsive electrical stimulation to the hippocampus on emotionality and spatial learning and memory in rats

Objective To observe the effects of repeated subconvulsive electrical stimuli to the hippocampus on the emotional behavior and spatial learning and memory ability in rats.Methods One hundred and eight male Wistar rats were randomized into 3 groups. Animals in group SE (n=42) were given subconvulsive electrical stimulation to the hippocampus through a constant pulsating current of 100 μA with an intratrain frequency of 25 Hz, pulse duration of 1 millisecond, train duration of 10 seconds and interstimulus interval of 7 minutes, 8 times a day, for 5 days. In the electrode control group or CE group (n=33), animals were implanted with an electrode in the hippocampus, but were not stimulated. Group NC (n=33) animals received no electrode or any stimulation. The emotional behavior of experimental rats was examined by activity in an unfamiliar open field and resistance to capture from the open field, while the spatial learning and memory ability was measured during training in a Morris water maze.Results The stimulated rats tested 1 month after the last round of stimulation displayed substantial decreases in open field activity (scale: 10.4±2.3, P&lt;0.05) and increases in resistance to capture (scale: 2.85±0.56, P&lt;0.01). The amount of time for rats in group SE to find the platform (latency) as a measurement for spatial bias was prolonged (29±7) seconds after 15 trials in the water maze, P&lt;0.05). The experimental rats swam aimlessly in all four pool quadrants during the probe trial in the Morris water maze.Conclusions Following repeated subconvulsive electrical stimuli to the hippocampus, rats displayed long-lasting significant abnormalities in emotional behavior, increased anxiety and defensiveness, enhanced ease to and delayed habituation to startlement, transitory spatial learning and memory disorder, which parallels many of the symptoms in posttraumatic stress disorder patients.     

Injection of bradykinin or cyclosporine A to hippocampus induces Alzhei mer- like phosphorylation of Tau and abnormal behavior in rats

Objective To reconstitute an Alzheimer’s disease model by administering bradykinin (BK) or cyclosporine A (CSA) to the rat hippocampus.Methods BK or CSA was administered to the rat hippocampus using a stereotaxic apparatus.The behavior of the rats was observed with an electronic attack-jump platform.The phosphorylation of Tau protein was examined through immunohistochemical assay.Results Behavior studies showed that an obvious disturbance in learning and memory was seen in BK injected rats.No obvious dysfunction was observed in CSA injected rats.The results obtained by immunohistochemical assay indicated that the staining of M4, 12E8, paired helical filament-1 (PHF-1) and calcium/calmodulin-dependent protein kinase Ⅱ (CaMKⅡ) was stronger, and that of Tau-1 was weaker in BK injected rats compared with the control group.We also found that the binding of M4 and PHF-1 but not 12E8 to Tau was significantly increased in CSA injected rats.As for BK injection, binding of Tau-1 to Tau was decreased after CSA injection.Conclusion To our knowledge, this is the first data showing in vivo that the activation of CaMKⅡ induces both Alzheimer-like Tau phosphorylation and behavioral disturbances.     

Huannao Yicong Decoction (还脑益聪方) extract reduces inflammation and cell apoptosis in Aβ1-42-induced Alzheimer's disease model of rats

Objective: Huannao Yicong Decoction (还脑益聪方, HYD), an effective herbal formula against Alzheimer''s disease (AD), has been proven to have neuroprotective action in amyloid β-protein1-42 (Aβ1-42)-induced rat model. This study was designed to characterize mechanisms by which HYD leads to suppression of inflammation and apoptosis in the brains of Aβ1-42-induced rat. Methods: A total of 72 rats were divided into 6 groups, which were referred to as: sham operation group, model group, donepezil-treated group, HYD low-dose group (HYDL), HYD middle-dose group (HYDM) and HYD high-dose group (HYDH). Rats in HYDL, HYDM and HYDH were injected with Aβ1-42 at the CA1 region of hippocampus to form AD model and were fed the HYD extract at different dose of 3.78, 7.56 and 18.90 g crude drug/kg. The behavioral changes of rats were evaluated by Morris water maze (MWM) before sacrifice. Pathological changes of the brain tissue were evaluated using hematoxylin eosin (HE) staining. The levels of interleukin-1 (IL-1) and tumor necrosis factor-α (TNF-α) were measured by radioimmunoassay. The levels of Aβ and proteins that are associated with apoptosis such as B-cell lymphoma-2 protein (Bcl-2), Bcl-2-associated X protein (Bax), cysteine-aspartic protease (caspase)-3, -8, -9 and -12 in serum were measured by immunohistochemistry. Results: Compared with the sham operation group, the spatial learning and memory abilities of AD rats were significantly decreased (P<0.05 or P<0.01; Expressions of IL-1, TNF-α, Aβ and apoptosis-signaling proteins caspase-3, -8, -9, -12 were significantly up-regulated (P<0.05 or P<0.01). The ratio of Bcl-2 to Bax were significantly decreased in the model group (P<0.01). When treated with HYD extract, the spatial learning and memory abilities of AD-model rats were significantly increased (P<0.05 or P<0.01), IL-1, TNF-α, Aβ, caspase-3, -8, -9 and -12 were down-regulated (P<0.05 or P<0.01), and the ratio of Bcl-2 to Bax were reduced (P<0.05 or P<0.01). Conclusions: HYD extract can improve the learning and memory ability deficits, alleviate the inflammatory response and pathological manifestations induced by Aβ1-42 injection in the rat model of AD. HYD down-regulates the levels of IL-1, TNF-α and Aβ, and decreases the rate of apoptosis by modulating apoptosis-signaling-related proteins such as caspase-3, -8, -9, and -12.     

Huannao Yicong Decoction(还脑益聪方) Extract Reduces Inflammation and Cell Apoptosis in Aβ_(1-42)-Induced Alzheimer's Disease Model of Rats

Objective: Huannao Yicong Decoction(还脑益聪方, HYD), an effective herbal formula against Alzheimer's disease(AD), has been proven to have neuroprotective action in amyloid β-protein_(1-42))(Aβ_(1-42))-induced rat model. This study was designed to characterize mechanisms by which HYD leads to suppression of inflammation and apoptosis in the brains of Aβ_(1-42)-induced rat. Methods: A total of 72 rats were divided into 6 groups, which were referred to as: sham operation group, model group, donepezil-treated group, HYD low-dose group(HYDL), HYD middle-dose group(HYDM) and HYD high-dose group(HYDH). Rats in HYDL, HYDM and HYDH were injected with Aβ_(1-42) at the CA1 region of hippocampus to form AD model and were fed the HYD extract at different dose of 3.78, 7.56 and 18.90 g crude drug/kg. The behavioral changes of rats were evaluated by Morris water maze(MWM) before sacrifice. Pathological changes of the brain tissue were evaluated using hematoxylin eosin(HE) staining. The levels of interleukin-1(IL-1) and tumor necrosis factor-α(TNF-α) were measured by radioimmunoassay. The levels of Aβ and proteins that are associated with apoptosis such as B-cell lymphoma-2 protein(Bcl-2), Bcl-2-associated X protein(Bax), cysteine-aspartic protease(caspase)-3,-8,-9 and-12 in serum were measured by immunohistochemistry. Results: Compared with the sham operation group, the spatial learning and memory abilities of AD rats were significantly decreased(P0.05 or P0.01; Expressions of IL-1, TNF-α, Aβ and apoptosis-signaling proteins caspase-3,-8,-9,-12 were significantly up-regulated(P0.05 or P0.01). The ratio of Bcl-2 to Bax were significantly decreased in the model group(P0.01). When treated with HYD extract, the spatial learning and memory abilities of AD-model rats were significantly increased(P0.05 or P0.01), IL-1, TNF-α, Aβ, caspase-3,-8,-9 and-12 were down-regulated(P0.05 or P0.01), and the ratio of Bcl-2 to Bax were reduced(P0.05 or P0.01). Conclusions: HYD extract can improve the learning and memory ability deficits, alleviate the inflammatory response and pathological manifestations induced by Aβ_(1-42) injection in the rat model of AD. HYD down-regulates the levels of IL-1, TNF-α and Aβ, and decreases the rate of apoptosis by modulating apoptosis-signaling-related proteins such as caspase-3,-8,-9, and-12.     

Effects of chronic multiple stress on learning and memory and the expression of Fyn, BDNF, TrkB in the hippocampus of rats

Background The effect of chronic stress on cognitive functions has been one of the hot topics in neuroscience. But there has been much controversy over its mechanism. The aim of this study was to investigate the effects of chronic multiple stress on spatial learning and memory as well as the expression of Fyn, BDNF and TrkB in the hippocampus of rats. Methods Adult rats were randomly divided into control and chronic multiple stressed groups. Rats in the multiple stressed group were irregularly and alternatively exposed to situations of vertical revolution, sleep expropriation and restraint lasting for 6 weeks, 6 hours per day with night illumination for 6 weeks. Before and after the period of chronic multiple stresses, the performance of spatial learning and memory of all rats was measured using the Morris Water Maze （MWM）. The expression of Fyn, BDNF and TrkB proteins in the hippocampus was assayed by Western blotting and immunohistochemical methods. The levels of Fyn and TrkB mRNAs in the hippocampus of rats were detected by RT-PCR technique. Results The escape latency in the control group and the stressed group were 15.63 and 8.27 seconds respectively. The performance of spatial learning and memory of rats was increased in chronic multiple stressed group （P〈0.05）. The levels of Fyn, BDNF and TrkB proteins in the stressed group were higher than those of the control group （P〈0.05）. The results of immunoreactivity showed that Fyn was present in the CA3 region of the hippocampus and BDNF positive particles were distributed in the nuclei of CA1 and CA3 pyramidal cells as well as DG granular cells. Quantitative analysis indicated that level of Fyn mRNA was also upregulated in the hippocampus of the stressed group （P〈0.05）. Conclusions Chronic multiple stress can enhance spatial learning and memory function of rats. The expression of Fyn, BDNF and TrkB proteins and the level of Fyn mRNA are increased in the stessed rat hippocampus. These suggest that Fyn and BDNF/TrkB signal transduction pathways may participate in the process of the enhanced learning and memory durina chronic multiple stress.     

Behavioral Abnormality along with NMDAR-related CREB Suppression in Rat Hippocampus after Shortwave Exposure

Objective To estimate the detrimental effects of shortwave exposure on rat hippocampal structure and function and explore the underlying mechanisms. Methods One hundred Wistar rats were randomly divided into four groups(25 rats per group) and exposed to 27 MHz continuous shortwave at a power density of 5, 10, or 30 m W/cm^2 for 6 min once only or underwent sham exposure for the control. The spatial learning and memory, electroencephalogram(EEG), hippocampal structure and Nissl bodies were analysed. Furthermore, the expressions of N-methyl-D-aspartate receptor(NMDAR) subunits(NR1, NR2 A, and NR2 B), c AMP responsive element-binding protein(CREB) and phosphorylated CREB(p-CREB) in hippocampal tissue were analysed on 1, 7, and 14 days after exposure. Results The rats in the 10 and 30 m W/cm^2 groups had poor learning and memory, disrupted EEG oscillations, and injured hippocampal structures, including hippocampal neurons degeneration, mitochondria cavitation and blood capillaries swelling. The Nissl body content was also reduced in the exposure groups. Moreover, the hippocampal tissue in the 30 m W/cm^2 group had increased expressions of NR2 A and NR2 B and decreased levels of CREB and p-CREB. Conclusion Shortwave exposure(27 MHz, with an average power density of 10 and 30 m W/cm^2) impaired rats' spatial learning and memory and caused a series of dose-dependent pathophysiological changes. Moreover, NMDAR-related CREB pathway suppression might be involved in shortwave-induced structural and functional impairments in the rat hippocampus.     

蛇床子素减轻Aβ（25-35）诱导的大鼠学习记忆减退及海马神经元结构损伤

目的观察蛇床子素对-淀粉样蛋白25-35片段（Aβ25-35）诱导的大鼠学习记忆减退及海马神经元结构损伤的影响。方法 40只雄性SD大鼠随机均分为假手术组、模型组、阳性药组及蛇床子素组,阳性药组每日1次灌胃多奈哌齐1 mg/kg,蛇床子素组每日1次灌胃蛇床子素40 mg/kg,连续17 d,假手术组、模型组灌胃等体积的生理盐水,3 d后右侧脑室注射Aβ25-35制模,制模后d 10开始Morris水迷宫检测大鼠的空间记忆能力,透射电镜观察大鼠海马CA1区神经元结构损伤。结果右侧脑室注射Aβ25-35后,大鼠在定向航行实验中的逃避潜伏期明显增加（〈0.01）,空间探索实验中的校正逃避潜伏期缩短（〈0.01）,海马CA1区神经元结构明显受损;然而,蛇床子素及多奈哌齐明显缩短了大鼠的定向航行实验中的逃避潜伏期（〈0.01）,延长了空间探索实验中的校正逃避潜伏期（〈0.01）,减轻了海马CA1区神经元结构损伤。结论蛇床子素可减轻Aβ25-35诱导的大鼠学习记忆减退及海马神经元结构损伤。     

蜕皮甾酮改善Aβ25-35大鼠学习记忆功能障碍与ChAT相对高表达有关

目的探讨蜕皮甾酮(Ecdysterone,ECR)改善Aβ25-35诱导大鼠学习记忆功能障碍的作用机制。方法Wistar大鼠90只(♂)随机分为5组:对照组(control),模型组(Aβ),三个治疗组[ECR4mg.kg-1(Aβ ECR4),ECR8mg.kg-1(Aβ ECR8),Nimodipine7.2mg.kg-1(Aβ -Ni7.2)],每组18只。大鼠双侧海马内注射Aβ25-35(每侧5μl,2μg.μl-1)诱导学习记忆功能障碍;水迷宫检测Aβ25-35诱导的大鼠学习记忆行为学改变;免疫组化SP法检测ChAT表达情况;AchE活性由试剂盒检测。结果①行为学的水迷宫检测结果显示,在连续4天的获得实验期间,与对照组比较,模型组找到平台的潜伏期和搜索距离明显增加(P<0.01);与模型组比较,高剂量ECR组及尼莫地平组大鼠找到平台的潜伏期和搜索距离相对缩短(ECR8mg.kg-1,P<0.01;-Ni7.2mg.kg-1,P<0.05)。在第5天撤去平台的记忆测试中:与对照组比较,模型组在原平台区的搜索时间及距离均缩短(P<0.01),而治疗组平台区的搜索时间及距离则相对增加(ECR4mg.kg-1P<0.05;ECR8mg.kg-1,P<0.01;Ni7.2mg.kg-1,P<0.05)。②胆碱乙酰转移酶(cholineacetyltransferase,ChAT)的分析结果显示,与对照组比较,模型组大鼠皮层及海马脑组织中的ChAT活性均明显降低(bothP<0.01);与模型组比较,高剂量ECR组及尼莫地平组大鼠皮层脑组织中ChAT活性均相对增加(ECR8mg.kg-1,P<0.01;Ni7.2mg.kg-1,P<0.05),而海马组织中只有高剂量ECR组的ChAT活性相对增加(ECR8mg.kg-1,P<0.05)。③胆碱脂酶(Acetylcholinesterase,AchE)的检测结果显示,各组大鼠的AchE活性无明显差别。结论ECR改善Aβ25-35大鼠学习记忆功能障碍,至少与皮层及海马脑组织中ChAT活性相对增加有关。     

脑尔康对阿尔茨海默病模型大鼠海马β淀粉样肽1-42及脑啡肽酶表达的影响

目的：观察复方中药脑尔康对阿尔茨海默病（Alzheimers disease, AD）模型大鼠海马β淀粉样肽1-42（β-amyloid peptide 1-42,Aβ1-42）及其降解酶——脑啡肽酶（neprilysin, NEP）表达的影响,探讨其抗痴呆的作用机制。 方法：48只健康雄性SD大鼠随机分为空白对照组、模型组、吡拉西坦组和大、中、小剂量脑尔康组,每组8只。除空白对照组外,其余各组大鼠双侧海马CA1区各一次性注射凝聚态Aβ1-425 μL（2 μg/μL）制备AD模型,空白对照组注射等体积生理盐水。3个剂量脑尔康组大鼠给予脑尔康［60、30、15 g/（kg·d）］连续灌胃28 d,吡拉西坦组给予吡拉西坦［0.375 g/（kg·d）］灌胃,空白对照组和模型组给予等量生理盐水灌胃。采用Y型电迷宫检测大鼠学习记忆能力,采用免疫组织化学法检测海马内Aβ1-42和NEP的表达。 结果：大鼠海马注射Aβ1-42后,与空白对照组比较,模型组大鼠学习记忆能力下降,海马内Aβ1-42表达明显增多（P＜0.01）。用药干预28 d后,与模型组比较,吡拉西坦组和各剂量脑尔康组大鼠学习记忆能力改善（P＜0.05,P＜0.01）,海马内Aβ1-42的表达下降（P＜0.05,P＜0.01）,NEP的表达增加（P＜0.05,P＜0.01）,其中以大剂量脑尔康组效果最佳。 结论：复方中药脑尔康可能通过上调AD模型大鼠海马NEP的表达来降低Aβ1-42的含量,改善其学习记忆能力,发挥抗痴呆作用。     

EPO对Aβ_（1-42）所致AD样大鼠空间记忆的影响及作用机制

目的探讨erythropoietin（EPO）对Aβ1-42所致AD样大鼠空间记忆的影响及作用机制。方法 48只雄性Wistar大鼠随机分成4组：生理盐水对照组、AD模型组、rHu-EPO治疗组与脑复康阳性对照组,每组12只。通过海马注射Aβ1-42的方法建立模型组,rHu-EPO治疗组与脑复康阳性对照组在建立模型的基础上,分别给予腹腔注射rhEPO（5000IU/kg,隔日一次）和脑复康（40 mg/kg,每日一次）。术后第八天开始对各组进行Morris水迷宫空间记忆能力测试,使用Western blot技术检测各组大鼠synapsin1蛋白水平。结果与生理盐水组、rHu-EPO治疗组及脑复康组相比,AD组水迷宫测试潜伏期延长,synapsin1表达降低,差异均有统计学意义（P〈0.05）。EPO治疗组与脑复康组相比,水迷宫测试结果与synapsin1蛋白表达差异无统计学意义（P〉0.05）。结论 EPO可以显著改善AD样大鼠的空间记忆能力,其机制可能与提高synapsin1蛋白表达有关。     

黄芪对阿尔茨海默病模型大鼠学习记忆能力的影响

目的 观察黄芪对阿尔茨海默病模型大鼠学习记忆能力的影响,并初步探讨其作用机制.方法 将40只Wistar大鼠随机分成4组(每组10只),即阴性组(蒸馏水)、阳性组(脑复康)、黄芪小剂量组和黄芪大剂量组,用D-半乳糖50 mg/(kg·d)腹腔注射6周,建立大鼠亚急性衰老模型,并在此基础上往海马内注入Aβ1-40(4 μ...     

Huannao Yicong Formula (还脑益聪方) regulates γ-secretase activity through APH-1 and PEN-2 gene ragulation pathways in hippocampus of APP/PS1 double transgenic mice

Objective: To observe the effects of Huannao Yicong Formula (还脑益聪方, HYF) on learning and memory and it's regulating effect on γ-secretase related anterior pharynx defective 1 (APH-1), presenilin enhancer-2 (PEN-2) signaling pathway, so as to discuss and further clarify the mechanism of HYF on Alzheimer's disease. Methods: Sixty APP/PS1 transgenic mice, randomly allocated into 4 groups, the model group, the donepezil group (0.65 mg/kg), HYF low-dose group (HYF-L, 5.46 g/kg) and HYF high-dose group (HYF-H, 10.92 g/kg), 15 for each group. Another 15 C57BL/6J mice with the same age and same genetic background were allocated into the control group, proper dosage of drugs or distilled water were given by intragastric administration once daily for 12 weeks. After 12 weeks of administration, the learning and memory abilities of mice in each group was evaluated by the morris water maze test, amyloid precursor protein (APP), Aβ1-40 and Aβ1-42 levels in hippocampus were detected by enzyme-linked immunosorbent assay, γ-secretase was detected by dual luciferase assaying, the levels of APH-1a, hypoxia-inducible factor 1α (HIF-1α), cAMP response element-binding protein (CREB) and PEN-2 and their mRNA expression was measured by Western blot and real-time polymerase chain reaction. Results: HYF can ameliorate learning and memory deficits in APP/PS1 transgenic mice by decreasing the escape latency, improving the number of platform crossing and swimming speed (P<0.01, P<0.05). HYF can decrease the levels of APP, Aβ1-40 , Aβ1-42 and the activity of γ-secretase in hippocampus of Alzheimer's disease model mice. HYF can down-regulate the levels of CREB and PEN-2 and the expression of their mRNA. Conclusion: HYF can improve the learning and memory ability by inhibiting the activity of γ-secretase through the CREB/PEN-2 signaling pathway, and this may be one of the therapeutic mechanisms of HYF in Alzheimer's disease.     

红景天对血管性痴呆大鼠空间学习记忆能力及海马组织SOD、MDA影响的实验研究

目的：观察红景天对血管性痴呆（VD）大鼠空间学习记忆能力及大脑海马组织内超氧化物歧化酶（S0D）活性与丙二醛（MDA）含量的影响。方法：健康Wister雄性大鼠采用双侧颈总动脉永久性结扎法，造成慢性脑灌注不足所致VD模型。术后红景天组给予红景天5g／（kg·d）、尼莫地平组给予尼莫地平20mg／（kg·d）灌胃，假手术组与模型组以等量生理盐水灌胃。检测各组大鼠Morris水迷宫实验各项指标及海马组织SOD活性和MDA含量。结果：水迷宫数据、海马组织SOD活性及MDA含量，模型组与假手术组比较异有统计学意义（p〈0．05），红景天组及尼莫地平组与模型组比较差异有统计学意义（P〈0．05）。结论：红景天可以改善大鼠的学习记忆能力，提高大鼠大脑SOD活性，降低MDA含量。     

二烯丙基二硫对AD模型小鼠学习记忆能力和海马突触的影响

目的：探讨二烯丙基二硫（DADS）对阿尔茨海默病（AD）小鼠学习记忆能力及海马突触的影响。方法侧脑室立体定位术注射凝集态Aβ1-42制备AD模型小鼠,随机分成四组AD模型组,低中高DADS剂量组,分别灌服0、10、50和100 mg/kg/d的DADS。1个月后各组小鼠进行Morris水迷宫检测学习记忆能力、银染和电镜检测海马CA1区树突棘和突触的结构、蛋白印迹和RT-PCR检测海马内PSD95和SYP蛋白和基因的表达。结果与AD模型组相比,水迷宫检测显示中高剂量DADS组小鼠学习记忆能力增强,银染和电镜检测显示海马CA1区树突棘和突触增多,蛋白印迹和RT-PCR检测显示海马PSD95和SYP表达增多。结论随着DADS剂量的增加,AD小鼠的学习记忆能力得到改善,海马内树突棘和突触增多。     

不同浓度的Aβ31-35对大鼠学习记忆功能的影响

目的通过观察不同浓度的Aβ31-35对在体大鼠海马LTP和空间学习记忆功能的影响,探讨全长A片段的活性中心。方法急性手术后进行海马CA1区fEPSP的记录,比较给予不同的处理后海马LTP的变化;侧脑室注射药物2周后进行Morris水迷宫测试,比较不同处理后的大鼠逃避潜伏期、到达平台游过距离以及目标象限内游泳所占的时间和距离。结果高浓度的Aβ31-35可以引起大鼠在体海马LTP幅度的降低（P〈0.01或P〈0.05）、以及延长大鼠逃避潜伏期、到达平台游过距离（P〈0.01）,并且减低了大鼠在目标象限内游泳所用的时间和距离（P〈0.01）。结论高浓度的Aβ31-35能够引起大鼠学习记忆功能的损伤。     

D-半乳糖-Aβ复合造模致大鼠学习记忆功能障碍及丹参酮治疗作用的研究

目的研究拟老年痴呆症（alzheimer’s disease,AD）模型大鼠学习记忆功能的改变及丹参酮的治疗作用。方法（1）实验动物随机分成4组。AD-模型组：采用D-半乳糖腹腔注射和大鼠双侧海马齿状回背侧微量注射凝聚态β-淀粉样肽1-40（amyloid beta-peptide,Aβ1-40）的复合造模方法,拟建立AD样学习记忆障碍动物模型;丹参酮治疗组：AD大鼠造模24h后给予丹参酮[60mg／（kg·d）],溶于5mL玉米油中灌胃14d;假造模对照组：与AD大鼠同法注射等量生理盐水;正常对照组：大鼠不做任何处理。（2）采用水迷宫行为学实验检测各组大鼠的学习记忆功能。结果（1）AD模型大鼠发生了空间学习记忆功能障碍,与两对照组比较有显著性差异（P〈0．01）。（2）丹参酮治疗组治疗后较AD模型组潜伏期缩短、误入盲端次数也明显减少。结论（1）D-半乳糖-Aβ复合造模致AD样学习记忆功能障碍的动物模型具有较好的仿真AD的特点。水迷宫实验能较真实地反应动物学习记忆功能。（2）丹参酮对AD样大鼠的学习记忆功能障碍具有一定的改善作用。