重组人促红细胞生成素对脑缺血再灌注小鼠海马VEGF表达的影响

目的探讨重组人促红细胞生成素(recombinant human erythropoietin,rHuEPO)对脑缺血再灌注小鼠血管内皮生长因子(vascular endothelial growth factor,VEGF)表达的影响。方法 96只昆明小鼠随机分为3组,每组32只:假手术组(Sham);rHuEPO治疗组;缺血再灌注组(I/R)。每组依据缺血后再灌注不同时间点再分6h、24h、3d、7d五个小组。免疫组化和Westernblot检测各组小鼠VEGF的表达,TUNEL法检测海马细胞凋亡情况。结果缺血再灌注组海马VEGF蛋白表达量和凋亡细胞数明显高于假手术组(<0.05),与缺血再灌注组相比,rHuEPO治疗组VEGF蛋白表达量明显升高(<0.05),凋亡细胞数则明显少于缺血再灌注组(相似文献   

γ-促分泌酶抑制剂对脑缺血再灌注小鼠海马CREB表达的影响

目的研究γ-促分泌酶抑制剂MW167阻断Notch信号对脑缺血再灌注小鼠海马cAMP反应元件结合蛋白（CREB）表达的影响。方法72只昆明小鼠随机分为：假手术组（Sham,8只）、γ-促分泌酶抑制剂组（MW167,32只）、缺血再灌注组（I／R,32只）。γ-促分泌酶抑制剂组和I／R组依据缺血后再灌注的不同时间点再细分为1、3、7、14d4个亚组。应用免疫组织化学方法和Westernblot方法检测各组小鼠海马CREB蛋白的表达。结果免疫组织化学方法检测时发现．缺血处理后1d时,CREB表达迅速增高,之后持续激活,与假手术组相比,显著升高（P〈0．01）;与相同时间点的缺血组比较,MW167组的CREB蛋白阳性表达则明显升高（P〈0．05）;Westernblot方法也得到了相同的结论。结论γ-促分泌酶抑制剂很可通过上调CREB蛋白的表达参与脑缺血再灌注损伤的神经保护作用。     

NGF对局灶性脑缺血再灌注大鼠顶叶皮质CREB表达的上调作用

为探讨外源性神经生长因子(NGF)对局灶性脑缺血再灌注大鼠顶叶皮质cAMP反应元件结合蛋白(CREB)和磷酸化CREB(p-CREB)表达的影响,用线栓法制作局灶性脑缺血再灌注模型,应用免疫组织化学、WesternBlotting和图像分析方法检测大鼠缺血侧顶叶皮质CREB和p-CREB的表达。结果显示:缺血再灌注组CREB表达较假手术组减少,p-CREB表达高于假手术组(P<0.05);NGF组CREB和p-CREB表达高于缺血再灌注组(P<0.05)。以上结果表明NGF明显上调局灶性脑缺血再灌注大鼠顶叶皮质CREB和p-CREB的表达,NGF对缺血神经元的保护作用可能通过上调CREB和p-CREB的表达来实现。     

重组人促红细胞生成素对慢性脑缺血大鼠认知功能的影响

目的 探讨重组人促红细胞生成素（EPO）对慢性脑缺血大鼠认知功能的影响以及对PI3K/Akt信号通路的影响。方法 30只SD大鼠随机分为假手术组（sham）、模型组（model）、重组人促红细胞生成素组（EPO）组,每组10只,通过结扎双侧颈总动脉的方法复制慢性脑缺血大鼠模型。重组人促红细胞生成素组（5000 IU/kg）大鼠连续治疗15天。采用Morris水迷宫观察各组大鼠认知功能变化;尼式染色检测各组大鼠海马神经元数量;采用原位末端标记（TUNEL）检测海马神经元凋亡情况;免疫荧光染色检测各组大鼠突触标志蛋白突触素（SYP）、细胞骨架蛋白-95(PSD-95)及生长相关蛋白-43(GAP-43)的表达情况;Western blot检测PI3K/Akt信号通路相关蛋白PI3K、Akt及p-Akt蛋白的表达情况。结果 与模型组相比,重组人促红细胞生成素组大鼠逃避潜伏期明显缩短,穿越平台次数显著增加,处于原平台象限时间也显著缩短,海马神经元结构改善,尼氏小体数量增加,海马神经元凋亡数量显著减少,突触标志蛋白SYP、PSD-95及GAP-43表达显著增加,PI3K及p-Akt蛋白表达水平显著增加（P<0.05）。结论 重组人促红细胞生成素改善慢性脑缺血大鼠的认知功能与激活PI3K/Akt信号通路、改善突触功能相关。     

NGF对局灶性脑缺血再灌注大鼠海马和顶叶皮质内CREB mRNA表达的影响

探讨外源性神经生长因子(nervegrowthfactor,NGF)对局灶性脑缺血再灌注大鼠海马和顶叶皮质内的cAMP反应元件结合蛋白(cyclicAMPresponseelementbindingprotein,CREB)mRNA表达的影响。用线栓法制作大鼠局灶性脑缺血再灌注模型,运用原位杂交和图像分析技术检测大鼠缺血侧海马CA1区和顶叶皮质内CREBmRNA的表达。结果显示:缺血再灌注组缺血侧海马CA1区和顶叶皮质CREBmRNA阳性反应产物平均光密度(OD)比假手术组减少(P<0.05),NGF组CA1区和顶叶皮质内的CREBmRNA阳性产物平均光密度高于缺血再灌注组(P<0.05)。本研究结果提示NGF可以上调局灶性脑缺血再灌注大鼠海马和顶叶皮质缺血神经元CREBmRNA的表达,NGF对缺血神经元的保护作用可能通过激活CREB的转录与翻译,从而启动一系列信号通路来实现。     

重组人促红细胞生成素对脑缺血再灌注小鼠海马IL-1β表达的影响

目的探讨重组人促红细胞生成素(recombinant human erythropoietin,rhEPO)对脑缺血再灌注小鼠白介素-1β(interleukin-1β,IL-1β)表达的影响。方法 96只昆明小鼠随机分为3组,每组32只:假手术组(Sham);rHuEPO治疗组;缺血再灌注组(I/R)。每组依据缺血后再灌注不同时间点再分6 h、24 h、3 d、7 d 5个小组。免疫组化和Western blot检测各组小鼠IL-1β的表达。TUNEL法检测海马细胞凋亡情况。结果缺血再灌注组IL-1β蛋白表达量和凋亡细胞数明显高于假手术组(P<0.05),而rhEPO治疗组IL-1β蛋白表达量和凋亡细胞数则明显少于缺血再灌注组(P<0.05)。结论 rHuEPO很可通过下调IL-1β的表达参与脑缺血再灌注损伤。     

重组人促红细胞生成素改善小鼠创伤性脑损伤神经功能

目的探讨重组人促红细胞生成素(rhEPO)对小鼠创伤性脑损伤(TBI)血管生成及神经功能恢复的影响。方法将小鼠随机分为假手术组(sham组)、模型组(TBI组,控制性皮质撞击制作重型TBI模型)和治疗组[EPO组,损伤后连续7 d腹腔注射5000 IU/(kg·d)rhEPO],每组小鼠15只。伤后3、7和14 d进行神经功能缺损评分(mNSS),14 d以Western blot及免疫荧光法检测脑损伤灶周边区域eNOS、VEGF和CD31蛋白表达,并通过CD31+细胞进行微血管密度计数(MVD);21 d以苏木精-伊红(HE)染色大脑切片并检测损伤灶体积。结果伤后3、7及14 d,TBI组较sham组mNSS明显上升(P<0.001),伤后7及14 d EPO组mNSS低于TBI组(P<0.05)。伤后14 d,损伤灶周边区eNOS、VEGF和CD31蛋白的表达,TBI组较sham组升高(P<0.05),EPO组较TBI组升高(P<0.05);TBI组的MVD显著低于sham组(P<0.001),EPO组的MVD显著高于TBI组(P<0.001)。伤后21 d EPO组较TBI组创伤体积减小(P<0.05)。结论rhEPO促进小鼠TBI血管生成,改善颅脑损伤后神经功能。     

神经节苷脂对脑缺血再灌注大鼠海马CREB表达的影响

目的探讨单唾液酸神经节苷脂(GM1)对脑缺血再灌注大鼠海马cAMP反应元件结合蛋白(CREB)表达的影响。方法 72只SD大鼠随机分为:假手术组(Sham,8只)、神经节苷脂治疗组(GM1,32只)、缺血再灌注组(I/R,32只)。GM1治疗组和I/R组依据缺血后再灌注的不同时间点再细分为6h、12h,24h、3d,共4个小组。应用免疫组织化学方法和Western blot方法检测各组大鼠海马CREB蛋白的表达。结果免疫组织化学方法检测时发现,缺血处理后,CREB表达水平迅速增高,在6h时最高,之后持续激活,至12h时开始降低,与假手术组相比,CREB阳性产物的平均光密度值(MOD)显著升高(P0.01);与相同时间点的缺血组比较,GM1治疗组的CREB蛋白阳性表达水平明显升高(P0.01)。Western blot方法也得到了相同的结论。结论 GM1对脑缺血再灌注损伤的神经保护作用可能与上调CREB蛋白的表达相关。     

重组人促红细胞生成素对脑缺血再灌注小鼠海马水通道蛋白-1表达的作用

目的探讨重组人促红细胞生成素(recombinant human erythropoietin,rHuEPO)对脑缺血再灌注小鼠水通道蛋白-1(aquaporin1,AQP1)表达的作用。方法 96只昆明小鼠随机分为假手术组(Sham)、rHuEPO治疗组、缺血再灌注组(I/R),每组32只,依据缺血后再灌注不同时间点再细分6h、24h、3d、7d四个小组。利用免疫组织化学方法检测各组小鼠海马组织AQP1的表达;利用Westernblot方法检测各组小鼠海马AQP1的表达。结果免疫组化和Westernblot结果发现,缺血再灌注组AQP1蛋白表达量明显高于假手术组(P<0.05),而rHuEPO治疗组AQP1蛋白表达量则明显少于缺血再灌注组(P<0.05)。结论 rHuEPO能够下调脑缺血再灌注小鼠AQP1的表达。     

促红细胞生成素对大鼠脑缺血再灌注损伤的保护作用及细胞黏附分子-1表达的影响

目的:观察促红细胞生成素(EPO)预处理对大鼠局灶性脑缺血再灌注后脑组织的病理变化和细胞黏附分子-1(ICAM-1)表达的影响,探讨其保护作用.方法: 96只SD大鼠随机分为对照组、假手术组、模型组、EPO组,分设4个时间点的亚组,每亚组6只.采用Longa线栓法制备大鼠大脑中动脉阻塞2 h模型,再灌注6、24、48、96 h后行神经功能评分,H-E染色观察病理学变化,免疫组织化学方法测定各组ICAM-1阳性反应细胞.结果:24 h开始EPO组神经功能评分改善,神经细胞存活数量增多,损伤程度减轻,而且减少了各时间点脑组织中ICAM-1阳性细胞表达.结论: EPO处理可抑制缺血侧皮层的神经细胞变性坏死,其保护机制可能与脑缺血再灌注后炎症因子ICAM-1表达减少有关.     

气味对小鼠学习记忆能力及海马cAMP反应元件结合蛋白的影响

目的:探讨不同气味(苹果、香水、樟脑)对小鼠学习记忆能力及海马cAMP反应元件结合蛋白(CREB)和磷酸化的CREB(pCREB)的影响。方法:让小鼠在不同气味的环境下生活14d,在第7d开始方形水迷宫训练,3d后进行测试,连续测试5d。测试完后断髓处死动物,取出脑组织,用免疫组织化学染色观察海马pCREB和CREB表达情况,并进行图像分析。结果:樟脑组和香水组水迷宫的潜伏期较对照组延长,错误次数增多(P＜0.05)。免疫组化染色显示鼠海马CREB的磷酸化水平大大降低(P＜0.05),但对CREB的表达无明显影响。苹果组与对照组比各指标均无显著差异(P＞0.05)。结论:樟脑气味和香水气味对小鼠记忆能力有负面作用,且这种作用可能是通过降低CREB磷酸化水平而实现的。苹果气味对小鼠记忆能力无明显影响。     

Correlation of increased hippocampal Sumo3 with spatial learning ability in old C57BL/6 mice

Age-related impairment of learning and memory is a common phenomenon in humans and animals, yet the underlying mechanism remains unclear. We hypothesize that a small ubiquitin-related modifier (Sumo) might correlate with age-related loss of learning and memory. To test this hypothesis, the present study evaluated age-related spatial learning and memory in C57BL/6 mice (25 aged 7 months and 21 aged 25 months) using a radial six-arm water maze (RAWM). After the behavioral test, the protein expression of Sumo3 was determined in different brain regions using Western blotting. The results showed that the 25-month-old mice had longer latency and a higher number of errors in both learning and memory phases in the RAWM task than the 7-month-old mice. Compared to the latter, the former's level of Sumo3 protein was significantly increased in the dorsal and ventral hippocampus. For the 25-month-old mice, the number of errors and the latency in the learning phase negatively correlated with the Sumo3 level in the dorsal hippocampus. These results suggest that increased Sumo3 in the hippocampus may be correlated with spatial learning ability in old C57BL/6 mice.     

Simvastatin enhances hippocampal long-term potentiation in C57BL/6 mice

Statins inhibit 3-hydroxy-3-methylglutaryl CoA reductase, the rate-limiting enzyme in the cholesterol biosynthetic pathway, and they are widely used to control plasma cholesterol levels and prevent cardiovascular disease. However, emerging evidence indicates that the beneficial effects of statins extend to the CNS. Statins have been shown to improve the outcome of stroke and traumatic brain injury, and statin use has been associated with a reduced prevalence of Alzheimer's disease (AD) and dementia. However, prospective studies with statins in AD have produced mixed results. Recently, we reported that simvastatin, a widely used statin in humans, enhances learning and memory in non-transgenic mice as well as in transgenic mice with AD-like pathology on a mixed genetic background. However, the cellular and molecular mechanisms underlying the beneficial effects of simvastatin on learning and memory remain elusive. The present study was undertaken to investigate the effect of acute simvastatin treatment on hippocampal long-term potentiation (LTP), a cellular model of learning and memory, in brain slices from C57BL/6 mice. Our results demonstrate that a prolonged in vitro simvastatin treatment for 2–4 h, but not a short-term 20-min exposure, significantly increases the magnitude of LTP at CA3–CA1 synapses without altering basal synaptic transmission or the paired-pulse facilitation ratio in hippocampal slices. Furthermore, we show that phosphorylation of Akt (protein kinase B) is increased significantly in the CA1 region following 2-hour treatment with simvastatin, and that inhibition of Akt phosphorylation suppresses the simvastatin-induced enhancement of LTP. These findings suggest activation of Akt as a molecular pathway for augmented hippocampal LTP by simvastatin treatment, and implicate enhancement of hippocampal LTP as a potential cellular mechanism underlying the beneficial effects of simvastatin on cognitive function.     

Behavioral changes in aging female C57BL/6 mice

Using a range of tests we have studied alterations in behavior with advancing age in female C57BL/6 (of Jackson origin), the golden standard on which most genetically engineered mice are back-crossed. In parallel, growth and survival data were collected. In a protected environment the 90% and 75% cohort survival age was 20 and 25 months, respectively, and the 50% cohort survival was 32 months. In mice, body weight increases continuously until 15-20 months of age, while in advanced age whole body weight drops. The body mass loss in senescence is associated with emergence of other aged phenotype features such as kyphosis, balding and loss of fur-color.Our behavioral data show that aging modulates certain aspects of basic behavior in a continuous manner, like explorative and locomotor activities. Advanced age associates with an acceleration of behavioral impairments evident in most of the tests used, including motor skill acquisition and memory consolidation. However, certain domains of mouse behavior were well preserved also in advanced age such as thermal noxious threshold and working memory as assessed by an object recognition task. The decreased drive to explore is suggested to be a key factor underlying many aspects of reduced performance including cognitive capacity during aging. Behavioral aging affects genetically closely related individuals housed under strictly standardized conditions differentially (Collier, T.J., Coleman, P.D., 1991. Divergence of biological and chronological aging: evidence from rodent studies. Neurobiol. Aging, 12, 685-693; Ingram, D.K., 1988. Motor performance variability during aging in rodents. Assessment of reliability and validity of individual differences. Ann. N.Y. Acad. Sci., 515, 70-96). Consistent with this a subpopulation of the 28-month-old mice showed an explorative activity similar to young-adult mice and a significantly stronger preference for a novel object than aged mice with a less explorative behavior. Thus, subtle environmental factors and epigenetic modifications may be important modulators of aging.     

Hippocampal neuron and synaptophysin-positive bouton number in aging C57BL/6 mice

A loss of hippocampal neurons and synapses had been considered a hallmark of normal aging and, furthermore, to be a substrate of age-related learning and memory deficits. Recent stereological studies in humans have shown that only a relatively minor neuron loss occurs with aging and that this loss is restricted to specific brain regions, including hippocampal subregions. Here, we investigate these age-related changes in C57BL/6J mice, one of the most commonly used laboratory mouse strains. Twenty-five mice (groups at 2, 14, and 28–31 months of age) were assessed for Morris water-maze performance, and modern stereological techniques were used to estimate total neuron and synaptophysin-positive bouton number in hippocampal subregions at the light microscopic level. Results revealed that performance in the water maze was largely maintained with aging. No age-related decline was observed in number of dentate gyrus granule cells or CA1 pyramidal cells. In addition, no age-related change in number of synaptophysin-positive boutons was observed in the molecular layer of the dentate gyrus or CA1 region of hippocampus. We observed a significant correlation between dentate gyrus synaptophysin-positive bouton number and water-maze performance. These results demonstrate that C57BL/6J mice do not exhibit major age-related deficits in spatial learning or hippocampal structure, providing a baseline for further study of mouse brain aging.     

Estrous cycle regulates activation of hippocampal Akt, LIM kinase, and neurotrophin receptors in C57BL/6 mice

Estradiol modulates dendritic spine morphology and synaptic protein expression in the rodent hippocampus, as well as hippocampal-dependent learning and memory. In the rat, these effects may be mediated through nongenomic steroid signaling such as estradiol activation of the Akt and LIM kinase (LIMK) pathways, in addition to genomic signaling involving estradiol upregulation of brain-derived neurotrophic factor expression (BDNF). Due to the many species differences between mice and rats, including differences in the hippocampal response to estradiol, it is unclear whether estradiol modulates these pathways in the mouse hippocampus. Therefore, we investigated whether endogenous fluctuations of gonadal steroids modulate hippocampal activation of the Akt, LIMK, and the BDNF receptor TrkB in conjunction with spatial memory in female C57BL/6 mice. We found that Akt, LIMK, and TrkB were activated throughout the dorsal hippocampal formation during the high-estradiol phase, proestrus. Cycle phase also modulated expression of the pre- and post-synaptic markers synaptophysin and post-synaptic density 95. However, cycle phase did not influence performance on an object placement test of spatial memory, although this task is known to be sensitive to the complete absence of ovarian hormones. The findings suggest that endogenous estradiol and progesterone produced by the ovaries modulate specific signaling pathways governing actin remodeling, cell excitability, and synapse formation.     

自主运动后BALB/c和C57BL/6小鼠学习记忆行为学指标的分析比较

BACKGROUND: BALB/c and C57BL/6 mice are two inbred strains, but after voluntary movement, there is no report on how to scientifically reasonably select behavioral experiment methods and indicators and to evaluate the learning and memory abilities of mice.     

Peripheral lipopolysaccharide administration impairs two-way active avoidance conditioning in C57BL/6J mice

Peripheral administration of lipopolysaccharide (LPS) or interleukin-1 (IL-1) may lead to alterations of CNS function and behavioral changes designated "sickness behavior." Further, some experiments show evidence of LPS- and cytokine-mediated alterations in learning and memory. The current series of experiments examined the effects of a single or repeated intraperitoneal LPS injections, at a number of doses and time points before or after test sessions, on behavior in a two-way active avoidance conditioning paradigm. Subjects were able to avoid the mild shock stimulus, escape it, or fail to respond to it. Subjects treated with LPS at many, but not all, of the time points sampled showed impaired learning, by exhibiting significantly fewer avoidance responses than controls. Furthermore, an LPS-induced increase in non-cued inter-trial interval crossings was observed during the later days of testing, suggesting that a greater percentage of their avoidance responses was not conditioned and their behavior was less efficient. Taken together, the results suggest that LPS-treated animals showed a diminished association between conditioned stimulus (CS) and unconditioned stimulus (US). These results support the theory that peripheral immune stimuli may induce deleterious effects on learning, and extend the work to a negatively reinforced operant procedure.     

短暂性脑缺血对C57BL/6小鼠海马区神经发生的影响

目的:利用小鼠急性全脑缺血模型观察急性脑缺血对海马神经发生的影响。方法:将C57BL/6雄性小鼠(6~8周)随机分为脑缺血组和假手术组。采用双侧颈动脉结扎法建立短暂性全脑缺血模型;利用HE染色观察脑缺血后不同时间(1周,2周)海马区形态学变化;采用免疫组织荧光染色观察缺血后海马区caspase-3表达变化;利用Ed U染色观察缺血3 d、7 d、14 d和28 d后,海马区神经干细胞增殖变化;利用免疫组织荧光染色观察缺血3 d、7 d、14 d和28 d后,海马区nestin、胶质纤维酸性蛋白(GFAP)及少突胶质细胞特异蛋白(OSP)等蛋白表达变化,判断脑缺血对海马区神经干细胞分化的影响。结果:脑缺血7 d后,小鼠海马CA1区神经元数目减少,caspase-3阳性细胞增加(P0.05)。海马DG区Ed U阳性细胞数量在第3 d开始增加(P0.05),第1周达到峰值(P0.05);海马CA1区Ed U阳性细胞数量在缺血后1周开始增加(P0.05),缺血2周后逐渐降低。海马DG区nestin、GFAP及OSP阳性细胞数量均在缺血3 d后开始增加(P0.05),缺血1周后达到峰值(P0.05),2周后逐渐降低。海马CA1区GFAP及OSP阳性细胞数量在缺血3 d后开始增加(P0.05),缺血1周后达到峰值(P0.05),2周后逐渐降低。结论:脑缺血激活了海马DG区神经干细胞,使干细胞增殖,并向神经元、星形胶质细胞、少突胶质细胞分化,同时逐渐向CA1区迁移。     

Non-specific and specific stimulation of resistance against Leishmania donovani in C57BL/6 mice

Stimulation by intravenous injections of glucan, a beta 1,3 polyglucose, provided a significant degree of resistance in mice against Leishmania donovani. The response of C57BL/6 animals was dose-dependent. A single glucan injection before or after infection induced significant resistance but to a lesser degree than two or three injections. Immunization by injections of formalin-killed promastigotes with glucan via the subcutaneous or intravenous routes provided greater resistance than glucan or dead parasites alone against subsequent infection with viable parasites. Subcutaneous immunization with promastigotes from cultures passaged 10 times in vitro and those from cultures maintained for 25 passages elicited a similar degree of resistance against infection and induced positive skin test responsiveness against leishmanial antigen prior to infection.