碱性成纤维细胞生长因子改善血管性痴呆小鼠学习记忆功能：与清除氧自由基有关？

背景：血管性痴呆（Vascular Dementia,VD）是由一系列脑血管因素导致脑组织损害引起的痴呆综合征,患者表现为学习、记忆等功能障碍。bFGF具有神经保护功能。 目的: 研究拟血管性痴呆模型小鼠学习记忆功能的改变及bFGF的治疗作用。 设计、时间及地点: 随机对照动物实验,于2008-03/12在北华大学医学院完成。 材料: 昆明种小鼠60只,体重(30.0±3.12g),♀♂兼用,随机分成4组：正常组、假手术组、模型组、bFGF治疗组（bFGF组）。 方法：采用清醒小鼠反复脑缺血再灌注方法建立VD动物模型。假手术组只分离双侧颈总动脉,不阻断血流。正常组不做任何处理。bFGF组于手术后首次即刻给药,正常组、假手术组、模型组给予等体积生理盐水腹腔注射。 主要观察指标: 应用Morris水迷宫观察bFGF对血管性痴呆小鼠学习记忆的改善作用;尼氏染色观察病理形态学变化;生化分析方法检测脑组织中SOD、MDA的含量;应用Annexin V-F1TC /PI双标记流式细胞术检测海马神经元的凋亡情况。 结果: 与正常组比较,水迷宫实验显示模型组小鼠学习记忆功能明显下降,表现为潜伏期延长、穿越有效区的时间缩短、穿越平台的次数减少（P<0.01,P<0.05）。生化指标显示模型小鼠脑组织SOD的活性下降,MDA 的含量增加（P<0.01）;流式细胞术检测结果显示海马神经元凋亡率显著增加（P<0.01）。与模型组比较,bFGF能够改善小鼠的学习记忆能力,增加SOD活力降低MDA含量（P<0.01）,降低海马神经元的凋亡率（P<0.01）。 结论:（1）清醒小鼠反复脑缺血再灌注引起的学习记忆障碍的动物模型具有较好的仿真VD的特点。（2）bFGF对VD小鼠的学习记忆功能障碍具有一定的改善作用。其机制可能与改善自由基代谢和脂质过氧化反应抑制神经细胞凋亡有关。     

阿尔茨海默病APPswe/PS1dE9双转基因型与野生型小鼠学习记忆能力的比较

目的：比较不同年龄段阿尔茨海默病（AD）APPswe/PS1dE9双转基因型与野生型小鼠的学习记忆能力。方法：C57BL/6J雌鼠与C3H/HeJ雄鼠交配产下F1代,再将F1代与3月龄的APPswe/PS1dE9双转基因型小鼠交配产下F2代。提取F2代小鼠鼠尾DNA,PCR扩增目的基因并鉴定。依据是否含APP和PS1基因分为转基因型组和野生型对照组,小鼠分别于6、8月龄行Morris水迷宫实验,11月龄行Y迷宫实验检测学习记忆能力。结果：繁育F2代小鼠33只,其中转基因型组18只,野生型对照组15只。6月龄转基因型与野生型小鼠定位航行实验潜伏期的差异无统计学意义,空间探索实验目标象限时间和路程百分比的差异无统计学意义（P〉0.05）。与8月龄野生型小鼠比较,转基因型小鼠定位航行实验第1天潜伏期延长（P〈0.05）。与11月龄野生型小鼠比较,转基因型小鼠达到学会标准的训练次数增加（P〈0.05）。结论：ADAPPswe/PS1dE9双转基因型与野生型小鼠比较,于11月龄时出现学习记忆能力障碍。     

促红细胞生成素对血管性痴呆大鼠行为学及脑组织形态学的影响

目的永久性结扎双侧颈总动脉（2-VO）建立血管性痴呆（VaD）动物模型,观察EPO治疗对VaD大鼠行为学及脑组织形态学的影响。方法选用14～15月龄Wistar大鼠,应用水迷宫进行空间定向学习训练,将达到学会标准者随机分为3组：假手术（Sham）组、VaD组、VaD＋EPO腹部皮下注射治疗（EPO）组。2-VO制作VaD模型,应用水迷宫检测空间定向学习能力;行HE染色,透射电镜观察海马组织病理学变化。结果与Sham组比较,VaD组、EPO组2-VO后8周学习记忆能力均明显下降;VaD组2-VO术后8周海马CA1区锥体神经元细胞稀疏、肿胀,与VaD组相比,EPO组脑组织损伤程度明显减轻,学习记忆能力增强。结论2-VO可引起大鼠学习记忆能力下降,EPO治疗的VaD大鼠学习记忆能力明显增强;海马CA1区神经元的缺血损伤减轻可能是EPO改善VaD大鼠认知功能障碍的组织病理学基础。     

化学点燃癫痫大鼠在水迷宫中学习记忆能力的测定

目的 观察印防己毒（Picrotoxin,PTX)化学点燃癫痫大鼠在水迷宫中学习记忆能力与发作频率及类型的关系。为进一步研究癫痫患者记忆损害的治疗提供线索。方法 34只雄性SD大鼠随机分为点燃组和对照组。分别用PTX和生理盐水腹腔注射，根据点燃情况点燃组再分为全面发作（A），频繁发作（B）和部分发作（C）组，对照组即为迷宫训练（D）组。然后进行水迷宫行为测试，评价其学习记忆能力。结果 癫痫大鼠在水迷宫测定中，除B组第1天的成绩较对照组差外，其余各组及B组在第2，3，4、5天中寻找平台的潜伏期时间与对照组相比没有显著性差异。点燃各组对平台空间位置的记忆能力较对照组要差。差异有显著性。结论 首次用化学点燃模型研究癫痫大鼠在水迷宫中的学习记忆能力后发现。PTX化学点燃癫痫大鼠在水迷宫中学习记忆能力下降。发作频繁者学习记忆受损明显，但与发作的严重程度无关。     

咖啡因对小鼠空间学习记忆能力及有关脑区记忆相关蛋白CREB表达的影响

目的：研究咖啡因对小鼠空间学习记忆能力以及有关脑区记忆相关蛋白——环腺苷酸应答元件结合蛋白（CREB）表达的影响。方法：C57BL／6J小鼠45只随机分成3组：咖啡因小剂量组（10mg·kg^-1）、咖啡因大剂量组（50mg·kg^-1）及生理盐水对照组，均腹腔给药。采用Morris水迷宫评价空间记忆能力及Western blot检测CREB的表达量。结果：与大剂量组及生理盐水对照组相比，咖啡因小剂量组定位航行实验逃避潜伏期显著缩短；空间搜索实验穿越原平台位置的次数显著增多；海马组织CREB表达显著增加。结论小剂量咖啡因能够提高小鼠空间学习记忆能力，且增加海马区CREB的表达。     

丁香酚不同途径给药对昆明鼠的空间学习记忆的研究

目的 探讨丁香酚不同途径给药对昆明鼠的空间学习记忆的影响.方法 通过灌胃、嗅觉吸人和鼻腔滴入等不同途径给予丁香酚,用自主活动箱测定小鼠神经兴奋性以及用水迷宫测定小鼠空间学习记忆能力.结果 灌胃组、嗅觉吸人组、鼻腔滴人组的自主活动明显高于空白组小鼠自主活动;丁香酚嗅觉吸入组的水迷宫潜伏期明显小于空白组的水迷宫潜伏期.结论丁香酚通过嗅觉吸入的途径能更好地改善小鼠的学习记忆功能.     

影响小鼠Morris水迷宫成绩的因素探讨及改进措施

Morris水迷宫自英国心理学家Richard Morris于1981年首次使用以来,已成为一种研究与海马功能直接相关的空间学习记忆机制的标准模式,能较准确地反映动物的空间参考记忆能力[1].Morris水迷宫能为考察实验动物空间认知能力提供较多的评价指标,全面记录其认知加工过程,客观地反映其认知水平.但是,Morris水迷宫的实施过程中还有很多影响其准确性和可靠性的因素存在,如实验动物的选择、实验设计、实验的实施过程等.因此,笔者现就影响小鼠Morris水迷宫成绩的若干因素(Morris水迷宫自身因素及小鼠主观因素等)进行综述,以期为实验工作者们减少误差提供一些帮助.     

HSF1基因在空间学习记忆能力中的作用研究

目的探讨热休克因子1（heatshockfactor1,HSFI）在小鼠Morris水迷宫空间学习任务中的作用。方法HSFl＋／十小鼠12只,HSFI-／-小鼠12只,进入空间学习任务实验。小鼠在Morris水迷宫中训练7d后,处死,剥离前额叶,液氮冻存,Western blots检测磷酸化的细胞外调节蛋白激酶（phospho--Extracellular regulated proteinkinases,P—Erk1／2）表达水平。结果HSFI-／-小鼠在Morris水迷宫定向航行实验中,第1天至第7天逃避潜伏期均明显长于HSF1＋／＋小鼠（P〈0．05）。Western blots显示：HSFI-／-小鼠在Morris水迷宫学习任务中前额叶内P—Erk1／2水平明显低于HSF1＋／＋小鼠（P〈0．05）相应的脑区。结论HSF1在Morris水迷宫学习任务中能够维持前额叶Erk1／2激活,因而在Morris水迷宫空间学习任务中起着重要的作用。     

异氟醚麻醉引起大鼠空间记忆损伤的潜在分子机制

【摘要】目的 先前的研究表明异氟醚麻醉后的动物模型可出现学习和记忆能力的持续性降低,可达数周或数月。然而,其分子学的机制仍然不是很明确。已经明确的是海马PKA、PKC的表达与记忆的加工过程相关。本实验拟通过研究异氟醚麻醉对青、老年大鼠morris水迷宫训练成绩及海马CA1区脑神经元激酶系统的影响,探讨麻醉后脑神经元分子水平变化与行为学表现的相关性,为深入研究术后认知功能障碍的发生机制提供参考。方法 选择36只3月龄青年雄性SD大鼠和36只20月龄老年雄性SD大鼠,分别随机分为对照组（不麻醉）、训练组（不麻醉,行morris水迷宫训练）、异氟醚组（异氟醚1.2%;大鼠分别于2小时/4小时异氟醚麻醉后的2天/2周行Morris水迷宫训练）。Morris水迷宫连续进行5天,每天8次,记录逃避潜伏期变化,用以测试各组大鼠的空间学习记忆能力。行为学实验后立即杀鼠,取海马,应用免疫组化法和酶标法,半定量检测大鼠海马CA1区脑组织PKC、PKA的阳性表达和PKC、PKA的激酶活性。结果 行为学测试结果示：4小时异氟醚麻醉后,青、老年鼠的认知功能损害可持续至麻醉后2天至2周,且尤以老年鼠常见且程度严重,表现为学习速度和记忆质量均有所下降(P<0.05);与对照组相比,行Morris水迷宫训练后,大鼠海马CA1区PKA、PKC表达明显增加(P<0.05)。随麻醉时程的延长和年龄增加,麻醉引起大鼠海马脑区激酶系统的抑制作用也增加。结论 异氟醚麻醉后老年大鼠长期的空间记忆损伤与海马CA1区PKC、PKA的表达相关,蛋白激酶系统的抑制在麻醉后认知功能下降过程中起重要作用。     

无名质区注射Ibotenic酸对大鼠学习,记忆的影响

本文采用被动回避性条件反射方法——跳台试验和水迷宫法,观察了鼠脑双侧无名质区域注入 Ibotenic 酸后,对大鼠学习获得和记忆巩固能力的影响。学习和记忆能力的衡量指标是:1.大鼠自水迷宫起点游至终点所需要的时间和进入盲端的错误次数;2.跳台试验中从台上跳下双足触电的错误次数。实验结果表明:鼠脑的双侧无名质区破坏,可使大鼠的学习获得和记忆巩固能力均发生障碍。     

Impaired water maze learning performance in mu-opioid receptor knockout mice

Previous study has demonstrated that the lack of mu-opioid receptor decreased LTP in the dentate gyrus of the hippocampus, suggesting the possibility that the lack of mu-opioid receptor may accompany a change in learning and memory. However, no behavioral study has been undertaken to correlate LTP deficits with spatial memory impairment in mu-opioid receptor knockout mice. Therefore, the present study investigated the hypothesis that mu-opioid receptors contribute to learning and memory by using the Morris water maze, and comparing responses in wild type and mu-opioid receptor gene knockout mice. Our results indicated that mu-opioid receptor knockout mice showed a significant spatial memory impairment compared to wild type in the Morris water maze. This result suggests that the expression of mu-opioid receptor plays an important role in spatial learning and memory examined by Morris water maze.     

Age-dependent effects of environmental enrichment on spatial reference memory in male mice

Although environmental enrichment has been shown to improve various types of memory in young and aging mice, no study has directly compared the degree to which enrichment improves memory at different ages throughout the lifespan in male mice. Therefore, the present study investigated the effects of long-term continuous enrichment in young (3 months), middle-aged (15 months), and aged (21 months) male C57BL/6 mice. Spatial reference memory was tested in the Morris water maze. Results demonstrate that 24h/day environmental enrichment for approximately 6 weeks significantly improved spatial memory in the Morris water maze in aged males, but not in young or middle-aged males. These data also indicate that 24h exposure to complex enriched housing conditions increases the magnitude of enrichment-induced improvements in memory among aged mice relative to those previously reported by this lab and others.     

Recovery after chronic stress within spatial reference and working memory domains: correspondence with hippocampal morphology

Chronic stress results in reversible spatial learning impairments in the Morris water maze that correspond with hippocampal CA3 dendritic retraction in male rats. Whether chronic stress impacts different types of memory domains, and whether these can similarly recover, is unknown. This study assessed the effects of chronic stress with and without a post-stress delay to evaluate learning and memory deficits within two memory domains, reference and working memory, in the radial arm water maze (RAWM). Three groups of 5-month-old male Sprague-Dawley rats were either not stressed [control (CON)], or restrained (6 h/day for 21 days) and then tested on the RAWM either on the next day [stress immediate (STR-IMM)] or following a 21-day delay [stress delay (STR-DEL)]. Although the groups learned the RAWM task similarly, groups differed in their 24-h retention trial assessment. Specifically, the STR-IMM group made more errors within both the spatial reference and working memory domains, and these deficits corresponded with a reduction in apical branch points and length of hippocampal CA3 dendrites. In contrast, the STR-DEL group showed significantly fewer errors in both the reference and working memory domains than the STR-IMM group. Moreover, the STR-DEL group showed better RAWM performance in the reference memory domain than did the CON group, and this corresponded with restored CA3 dendritic complexity, revealing long-term enhancing actions of chronic stress. These results indicate that chronic stress-induced spatial working and reference memory impairments, and CA3 dendritic retraction, are reversible, with chronic stress having lasting effects that can benefit spatial reference memory, but with these lasting beneficial effects being independent of CA3 dendritic complexity.     

Adverse effect of combination of chronic psychosocial stress and high fat diet on hippocampus-dependent memory in rats

The combined effects of high fat diet (HFD) and chronic stress on the hippocampus-dependent spatial learning and memory were studied in rats using the radial arm water maze (RAWM). Chronic psychosocial stress and/or HFD were simultaneously administered for 3 months to young adult male Wister rats. In the RAWM, rats were subjected to 12 learning trials as well as short-term and long-term memory tests. This procedure was applied on a daily basis until the animal reaches days to criterion (DTC) in the 12th learning trial and in memory tests. DTC is the number of days that the animal takes to make zero error in two consecutive days. Groups were compared based on the number of errors per trial or test as well as on the DTC. Chronic stress, HFD and chronic stress/HFD animal groups showed impaired learning as indicated by committing significantly (P < 0.05) more errors than untreated control group in trials 6 through 9 of day 4. In memory tests, chronic stress, HFD and chronic stress/HFD groups showed significantly impaired performance compared to control group. Additionally, the stress/HFD was the only group that showed significantly impaired performance in memory tests on the 5th training day, suggesting more severe memory impairment in that group. Furthermore, DTC value for above groups indicated that chronic stress or HFD, alone, resulted in a mild impairment of spatial memory, but the combination of chronic stress and HFD resulted in a more severe and long-lasting memory impairment. The data indicated that the combination of stress and HFD produced more deleterious effects on hippocampal cognitive function than either chronic stress or HFD alone.     

Impaired memory and olfactory performance in NaSi-1 sulphate transporter deficient mice

In the present study, NaSi-1 sulphate transporter knock-out (Nas1-/-) mice, an animal model of hyposulphataemia, were examined for spatial memory and learning in a Morris water maze, and for olfactory function in a cookie test. The Nas1-/- mice displayed significantly (P<0.05) increased latencies to find an escape platform in the reversal learning trials at 2 days but not 1 day after the last acquisition trial in a Morris water maze test, suggesting that Nas1-/- mice may have proactive memory interference. While the wild-type (Nas1+/+) mice showed a significant (P<0.02) decrease in time to locate a hidden food reward over four trials after overnight fasting, Nas1-/- mice did not change their performance, resulting in significantly (P<0.05) higher latencies when compared to their Nas1+/+ littermates. There were no significant differences between Nas1-/- and Nas1+/+ mice in the cookie test after moderate food deprivation. In addition, both Nas1-/- and Nas1+/+ mice displayed similar escape latencies in the acquisition phase of the Morris water maze test, suggesting that learning, motivation, vision and motor skills required for the task may not be affected in Nas1-/- mice. This is the first study to demonstrate an impairment in memory and olfactory performance in the hyposulphataemic Nas1-/- mouse.     

Reduced thyroid hormones with increased hippocampal SNAP-25 and Munc18-1 might involve cognitive impairment during aging

The mechanism underlying the decline of age-related learning and memory remains unclear. Brain-region-specific changes of synaptic proteins and decreased thyroid hormones (THs) have been implied involving this decline. During normal aging, however, the relationships among synaptic proteins, THs and abilities of learning and memory remain to be elucidated. In this study, the age-related spatial learning and memory ability of 41 Kunming mice (KM) (14 mice aged 6 months, 13 mice aged 11 months, 14 mice aged 22 months) was measured with radial six-arm water maze. The levels of SNAP-25 and Munc18-1 in brain regions were semi-quantified by Western blotting and the serum THs were detected by radioimmunoassay. Our results showed the old Kunming mice had marked impairment of spatial learning and memory, with decreased serum free triiodothyronine (FT3) and increased SNAP-25 and Munc18-1 in dorsal hippocampus (DH), ventral hippocampus (VH) and frontal lobe (F). The Pearson's correlation test showed the impairment of spatial learning ability positively correlated with SNAP-25 in DH and Munc18-1 in DH and VH. While, the levels of SNAP-25 (DH, VH and F) and Munc18-1 (DH) negatively correlated with the serum FT3 level, and the spatial memory decline marginal negatively correlate with serum THs. These results suggested that increased hippocampal SNAP-25 and Munc18-1 which seemingly result from decreased serum THs might involve the age-related impairment of spatial learning and memory.     

Early life seizures cause long-standing impairment of the hippocampal map

Children with seizures are at risk for long-term cognitive deficits. Similarly, recurrent seizures in developing rats are associated with deficits in spatial learning and memory. However, the pathophysiological bases for these deficits are not known. Hippocampal place cells, cells that are activated selectively when an animal moves through a particular location in space, provides the animal with a spatial map. We hypothesized that seizure-induced impairment in spatial learning is a consequence of the rat's inability to form accurate and stable hippocampal maps. To directly address the cellular concomitants of spatial memory impairment, we recorded the activity of place cells from hippocampal subfield CA1 in freely moving rats subjected to 100 brief flurothyl-induced seizures during the first weeks of life and then tested them in the Morris water maze and radial-arm water maze followed by place cell testing. Compared to controls, rats with recurrent seizures had marked impairment in Morris water maze and radial-arm water maze. In parallel, there were substantial deficits in action potential firing characteristics of place cells with two major defects: i) the coherence, information content, center firing rate, and field size were reduced compared to control cells; and ii) the fields were less stable than those in control place cells. These results show that recurrent seizures during early development are associated with significant impairment in spatial learning and that these deficits are paralleled by deficits in the hippocampal map. This study thus provides a cellular correlate for how recurrent seizures during early development lead to cognitive impairment.     

Spatial learning deficits in Parkinson's disease with and without mild cognitive impairment

BackgroundSeveral MRI studies have demonstrated hippocampal atrophy in Parkinson's disease (PD), a structure considered a key element in spatial learning. Despite this, no study has been undertaken to investigate spatial navigation in PD using a virtual version of the Morris water maze, which is the gold standard for testing hippocampal function in rodents.MethodsWe studied 17 cognitively unimpaired PD patients, 12 PD patients with mild cognitive impairment (MCI) and 15 controls in a virtual water maze procedure.ResultsMeasured by the main outcome parameters latency to locate the target and heading error (average difference between direction of movement toward anticipated target and real direction toward the target), controls performed significantly better on the virtual water maze task than cognitively unimpaired PD patients or PD patients with MCI, while there was no significant difference between latter two groups.ConclusionsThe virtual water maze test differentiates PD patients from controls, but does not distinguish between cognitively normal and cognitively impaired PD patients, indicating a possible dopamine dependent component in spatial learning. Spatial performance deficits might thus constitute very early signs of dopamine depletion independent of the presence of MCI in Parkinson's disease.     

The mixture of procyanidins extracted from the lotus seed pod and bilobalide ameliorates scopolamine-induced memory impairment in mice

Objective

To study the co-effect of procyanidins extracted from the lotus seed pod (LSPC) and bilobalide (BIL) on ameliorating scopolamine-induced learning and memory impairment in young mice.

Methods

Fifty male Kunming mice with similar learning and memory capabilities were selected by Morris water maze test and were randomized into 5 groups (n=10 in each group): control group, scopolamine group, L-(LSPC+BIL) group (50 mg/kg LSPC+10 mg/kg BIL), M-(LSPC+BIL) group (100 mg/kg LSPC+20 mg/kg BIL), H-(LSPC+BIL) group (150 mg/kg LSPC+30 mg/kg BIL). Scopolamine model with impaired learning and memory was established by scopolamine treatment (1 mg/kg), and after 10 min mice were tested. In L-, M-, and H-(LSPC+BIL) groups, mice were treated with LSPC and BIL ig. for 30 days, while mice in the other 2 groups were treated with normal saline ig. instead. After the 30-day’s treatment, the co-effect of LSPC and BIL on learning and memory was tested by Morris water maze and the step-down avoidance tests.

Results

The memory impairment caused by scopolamine in young mice could be ameliorated by co-treatment of LSPC and BIL, as indicated by significantly shorter escape latency and swimming distance in the Morris water maze test, when compared with those in the scopolamine group. In the step-down avoidance test, mice in all the 3 dose groups showed significantly smaller number of errors and longer latency than mice in the scopolamine group did.

Conclusion

Co-treatment of LSPE and BIL can ameliorate scopolamine-induced learning and memory impairment in young mice.     

LP-BM5 infection impairs spatial working memory in C57BL/6 mice in the Morris water maze

Previous studies show that the LP-BM5 murine leukemia virus causes an acquired immunodeficiency syndrome in C57BL/6 mice (MAIDS) and impairs learning and memory without gross motor impairment. To assess spatial working memory impairment after LP-BM5 infection and the time course of this impairment, we tested mice in a modified working-memory version of the Morris water maze. Twenty mice were inoculated with LP-BM5; controls received medium (Minimum Essential Medium). In the test procedure, animals had two 1-min training sessions to learn the position of a randomly placed hidden platform. Thirty seconds after the second training session, animals were placed in the maze without the platform, and time and pathlength spent in each quadrant of the maze were measured. For 9 weeks after LP-BM5 infection, both groups showed preference for the target quadrant compared to the opposite quadrant. At 10 and 11 weeks after infection, the LP-BM5 virus infected mice lost this target quadrant preference. We conclude that LP-BM5 infection impaired spatial working memory in a modified working-memory version of the Morris water maze test in C57BL/6 mice at 10 and 11 weeks after virus infection.