Effect of Kangshuai Yizhi Formula I (抗衰益智方 I) on learning and memory dysfunction induced by scopolamine in mice

Objective：To evaluate the improvement of Kangshuai Yizhi FormulaⅠ（抗衰益智方Ⅰ,KYFⅠ）on the learning and memory dysfunction in mice,and on the mechanism of the hippocampal cholinergic system and the nervous system of monoamine which are closely related to learning and memory function.Methods：Mice in the low-,middle-,and high-dose KYFⅠgroups were given low-,middle-,and high-dose KYF,respectively, by gastrogavage for 35 successive days.Animals in the control group and the model group were treated with distilled water.The acute learning and memory dysfunction model was established by injection of scopolamine from day 31,and Morris water maze was used to assess the behavior performance of scopolamine-induced model mice for five days.The activities of acetylcholinesterase（AChE）,choline acetyl transferase（ChaT） and the content of monoamine neurotransmitters in hippocampus were measured.The activity of monoamine oxidase（MAO）in hippocampus and serum was also detected.Results：（1）Compared with the control group,the mean escape latency was shortened,and the frequency across the platform and the staying time at the platform area on the 5th day were decreased in the model group by Morris water maze test.The activities of AChE and MAO were increased,and the ChaT activity and monoamine neurotransmitter content were decreased as well.（2） The escape latency for 4 days in the low-,middle-,and high-dose KYFⅠgroups was significantly shortened than that in the model group,with the shortest latency in the high-dose KYFⅠgroup（P〈0.05,P〈0.01）.The frequency across the platform was significantly increased and the staying time at the platform was significantly prolonged in the middle-and high-dose KYFⅠgroups（P〈0.05,P〈0.01）.（3）As compared with the model group,the activity of ChaT and the content of monoamine neurotransmitters in the hippocampus were significantly increased, and the activities of AchE and MAO were significantly decreased in the hippocampus in the high-dose KYFⅠgroup（P〈0.01）.Conclusions：High-dose KYFⅠcan significantly improve the learning and memory dysfunction induced by scopolamine in mice.Its mechanism may be related to improving the central cholinergic system and regulating the hippocampal monoamine neurotransmitters.     

Effects of unpredictable chronic stress on behavior and brain- derived neurotrophic factor expression in CA3 subfield and dentate gyrus of the hippocampus in different aged rats

Background Brain-derived neurotrophic factor （BDNF） is a stress-responsive intercellular messenger modifying hypothalamic-pituitary-adrenal （HPA） axis activity. The interaction between stress and age in BDNF expression is currently not fully understood. This study was conducted to observe unpredictable stress effect on behavior and BDNF expression in CA3 subfield （CA3） and dentate gyrus of hippocampus in different aged rats. Methods Forty-eight Wistar rats of two different ages （2 months and 15 months） were randomly assigned to six groups： two control groups and four stress groups. The rats in the stress group received three weeks of unpredictable mild stress. The depression state and the stress level of the animals were determined by sucrose preference test and observation of exploratory behavior in an open field （OF） test. The expressions of BDNF in CA3 and dentate gyrus of the hippocampus were measured using immunohistochemistry. Results Age and stress had different effects on the behavior of different aged animals （age： F=6.173, P〈0.05, stress： F=6.056, P 〈0.05）. Stress was the main factor affecting sucrose preference （F=123.608, P 〈0.05）. Decreased sucrose preference and suppressed behavior emerged directly following stress, lasting to at least the eighth day after stress in young animals （P 〈0.05）. The older stress rats showed a lower sucrose preference than young stress rats （P 〈0.05）. Older control rats behaved differently from the younger control animals in the OF test, spending more time in the central square （P 〈0.05）, exhibiting fewer vertical movements （P 〈0.05） and less grooming （P 〈0.05）. Following exposure to stress, older-aged rats showed no obvious changes in vertical movement and grooming. This indicates that aged rats were in an unexcited state before the stress period, and responded less to stressful stimuli than younger rats. There was significantly lower BDNF expression in the CA3 and dentate gyrus regions of the hippocampus following stress in both age groups （P〈0.05）, a reduction that was still present at the eighth day after stress （P〈0.05）. Stress and age were the main factors affecting the expression of BDNF （F=9.408, P 〈0.05; F=106.303, P 〈0.05）. The aged stress group showed lower BDNF expression compared to the young stressed group at every testing time point. Conclusion Stress has age-dependent effects on behavioral responses and hippocampal BDNF expression in rats.     

Increased Expression and Altered Subcellular Distribution of Cathepsin B in Microglia Induces Cognitive Impairment through Oxidative Stress and Inflammatory Response in Mice

Objective：During normal aging，innate immunity progresses to a chronic state. However，how oxidative stress and chronic neuroinflammation arise during aging remain unclear. In this study，we intended to demonstrate the novel function of Cathepsin B （CatB） in the age related oxidative stress and chronic neuroinfl ammation. Methods：①2 month-old and 20 month-old wild-type and CatB-/- mice were used for learning and memory tests by step through passive avoidance tests. The cumulative potentiation of the fi eld excitatory postsynaptic potential（ fEPSP） slope and dendritic spine density were also examined. ②Infl ammation were examined by immunoblotting of interleukin-1β（ IL-1β），tumor necrosis factor-α（ TNF-α） and inducible nitric oxide synthase（ iNOS），and oxidative stress were examined by checking the level of 8-oxo-7，8-dihydro-2’-deoxyguanosine （8-oxo-dG） and 4-hydroxynonenal（ 4-HNE） in the hippocampal lysate of 2 month-old and 20 month-old wild-type and CatB-/- mice. ③Intra-lateral ventricle transplantation of CatB over-expressed microglia in middleaged mice，learning and memory were examined by Y-maze and novel objective tests. Results：①The retention latencies of both aged groups were significantly longer than those in the acquisition trial. The retention latency of four consecutive trials was signifi cantly longer in aged CatB-/- mice than in aged wild-type mice. Furthermore，the mean relative fEPSP slope measured at 30 min after stimulationwith 25，50 and 100 Hz in the aged CatB-/- mice was significantly larger than that in the aged wildtype mice. The mean dendritic spine density of CA1 neurons in the aged CatB-/- mice was signifi cantly
larger than that in the aged wild-type mice. ②The mean levels of CatB，iNOS，IL-1β and TNF-α in the hippocampus were signifi cantly higher in aged wild-type mice than in younger animals. Furthermore， their mean levels in the hippocampus of aged CatB-/- mice were significantly lower than those in aged wild-type mice. The mean amounts of these oxidative markers were significantly larger in the hippocampus of aged wild-type mice than in younger animals. The mean relative amount of 8-oxodG and 4-HNE was significantly lower in aged CatB-/- mice than in aged wild-type mice. ③Double immunohistochemical staining was conducted to identify the possible cellular origin of oxidative stress. In the hippocampus of aged wild-type mice，the immunoreactivities of both 8-oxo-dG and 4-HNE were found exclusively in microglia with activated morphology，but not in astrocytes or neurons. ④Intralateral ventricle transplantation of CatB over-expressed microglia signifi cantly impaired the learning and memory in the middle-aged mice. Conclusion：CatB plays a critical role in the mitochondriaderived ROS generation and infl ammatory response，resulting in impairment of learning and memory during normal aging.     

Ginsenoside Rb1 Attenuates Isoflurane/surgery-induced Cognitive Dysfunction via Inhibiting Neuroinflammation and Oxidative Stress

Objective Anesthetic isoflurane plus surgery has been reported to induce cognitive impairment. The underlying mechanism and targeted intervention remain largely to be determined. Ginsenoside Rb1 was reported to be neuroprotective. We therefore set out to determine whether ginsenoside Rb1 can attenuate isoflurane/surgery-induced cognitive dysfunction via inhibiting neuroinflammation and oxidative stress. Methods Five-months-old C57BL/6J female mice were treated with 1.4% isoflurane plus abdominal surgery for two hours. Sixty mg/kg ginsenoside Rb1 were given intraperitoneally from 7 days before surgery. Cognition of the mice were assessed by Barnes Maze. Levels of postsynaptic density-95 and synaptophysin in mice hippocampus were measured by Western blot. Levels of reactive oxygen species, tumor necrosis factor-α and interleukin-6 in mice hippocampus were measured by ELISA. Results Here we show for the first time that the ginsenoside Rb1 treatment attenuated the isoflurane/surgery-induced cognitive impairment. Moreover, ginsenoside Rb1 attenuated the isoflurane/surgery-induced synapse dysfunction. Finally, ginsenoside Rb1 mitigated the isoflurane/surgery-induced elevation levels of reactive oxygen species, tumor necrosis factor-α and interleukin-6 in the mice hippocampus. Conclusion These results suggest that ginsenoside Rb1 may attenuate the isoflurane/surgery-induced cognitive impairment by inhibiting neuroinflammation and oxidative stress pending future studies.     

Gene transfer of a β2-adrenergic receptor kinase inhibitor up-regulates the level of β2-adrenergic receptor and cAMP in the asthmatic murine lung

Objective： To investigate the effects of gene transfer of a β-adrenergic receptor（β-AR） kinase inhibitor（β ARIct） on pulmonary β2-adrenergic receptor and cAMP following β2-AR agonist treatment in asthmatic mice, and to analyze the relationship between the routes of gene delivery and the changes of β2AR and cAMP. Methods： BALB/c mice were sensitized and challenged by ovalbumin to establish the asthmatic model treated with βAR agonist （salbutamol injected intramuscularly）. The plasmid with the expression of βARKct was constructed and βARKct gene transfer was performed through intravenous injection or intratracheal instillation in asthmatic mice. The gene expression was measured with Western blot analysis, and the changes of pulmonary β-AR and cAMP evaluated by Radioimmunoassay. Results： The expression of tranfered βARKct gene was detectable in lungs and it was expressed more in the lungs of the mice receiving intratracheally plasmid than those receiving intravenously. The levels of βAR and cAMP were upregulated after using plasmid-βARKct to the asthmatic mice treated with βAR agonist. Conclusion： Our results indicated that there were down-regulation of βAR and cAMP in asthmatic mice treated with βAR agonist. Gene transfer of βARKct could inhibit the extent of the down-regulation of βAR and cAMP. The route of gene delivery could also affect the degree of up-regulation of βAR and cAMP. Gene transfer βARKct may provide a novel approach to the therapeutic strategy for asthma.     

Minocycline Attenuates Microglial Response and Reduces Neuronal Death after Cardiac Arrest and Cardiopulmonary Resuscitation in Mice

The possible role of minocycline in microglial activation and neuronal death after cardiac arrest(CA) and cardiopulmonary resuscitation(CPR) in mice was investigated in this study. The mice were given potassium chloride to stop the heart beating for 8 min to achieve CA, and they were subsequently resuscitated with epinephrine and chest compressions. Forty adult C57BL/6 male mice were divided into 4 groups(n=10 each): sham-operated group, CA/CPR group, CA/CPR+minocycline group, and CA/CPR+vehicle group. Animals in the latter two groups were intraperitoneally injected with minocycline(50 mg/kg) or vehicle(normal saline) 30 min after recovery of spontaneous circulation(ROSC). Twenty-four h after CA/CPR, the brains were removed for histological evaluation of the hippocampus. Microglial activation was evaluated by detecting the expression of ionized calcium-binding adapter molecule-1(Iba1) by immunohistochemistry. Neuronal death was analyzed by hematoxylin and eosin(H&E) staining and the levels of tumor necrosis factor-alpha(TNF-α) in the hippocampus were measured by enzyme-linked immunosorbent assay(ELISA). The results showed that the neuronal death was aggravated, most microglia were activated and TNF-α levels were enhanced in the hippocampus CA1 region of mice subjected to CA/CPR as compared with those in the sham-operated group(P<0.05). Administration with minocycline 30 min after ROSC could significantly decrease the microglial response, TNF-α levels and neuronal death(P<0.05). It was concluded that early administration with minocycline has a strong therapeutic potential for CA/CPR-induced brain injury.     

Preventive Effect of Genetic Knockdown and Pharmacological Blockade of CysLT1R on Lipopolysaccharide（LPS）-induced Memory Deficit and Neurotoxicity in vivo

The aim of the current study was to fi nd out the role of CysLT1R on lipopolysaccharide（LPS）-induced cognitive deficit and neurotoxicity. shRNA-mediated knockdown or pharmacological blockade（ by pranlukast） of CysLT1R were performed in ICR mice for 21 days prior to systemic infusion of LPS. From day 22,LPS was administered for 7 days and then a set of behavioral,histopathological and biochemical tests were employed to test memory neuroinflammation and apoptotic responses in the mouse hippocampus. LPS （only）-treated mice showed poor performance in both Morris water maze（MWM） and Y-maze tests. However,shRNA-mediated knockdown or pranlukast-treated blockade of CysLT1R improved performance of the mice in these tests. To find out the possible underlying mechanisms,we assessed several parameters such as microglial activation（ by immunohistochemistry）,level of CysLT1R （by WB and qRT-PCR） and the inflammatory/apoptotic pathways （by ELISA or TUNEL or WB） in the mouse hippocampus. LPS-induced memory impairment was accompanied by activation of microglia,higher levels of CysLT1R,IL-1β,TNF-α and nuclear NF-κB p65. LPS also caused apoptosis in the hippocampus as detected by TUNEL staining,further supplemented by detection of increased Caspase-3 and a reduced Bcl-2/Bax ratio. All of these adverse changes in the mouse hippocampus were inhibited by pretreatment with CysLT1R-shRNA and pranlukast. Through this study we suggest that CysLT1R shares a strong correlation with LPS-associated memory defi cit,neuroinflammation and apoptosis and CysLT1R could be a novel target for preventive measures to intervene the progression of Alzheimer’s disease（ AD）-like phenotypes.     

Experimental Study of Mouse Cytomegalovirus Infected Mice

In order to investigate the human cytomegalovirus (HCMV) infection,the mouse cytomegalovirus(MCMV) infected mice were experimentally studied 6 to 8 week old female BALB/C mice with immunosuppression were selected to undergo the MCMV inoculations:intracranial inoculation and peritoneal inoculation. MCMV of the infected mice in various organs and tissues were detected by usingβ-gal staining and in situ nucleic acid hybridization assay.The pathological changes were observed in HE staining and in situ nucleic acid hybridization assay.The pathological changes were observed in HE staining paraffin-embedded sections.It was found that all the MCMV infected mice showed the retardation of growth and development,and feather looseness.Both intracranial inoculation of 10^4 PFU viruses or peritoneal inoculation of 10^6PFU viruses resultedin the pathological changes,to some extent,of various organs and tissues in the mice,The pathological changes in liver were consistent with the amount ofβ-gal staining positive the viruses in the immunosuppressed mice subjected to intracranial inoculation could spread to whole body organs,while the viruses in the immunosuppressed mice subjected to intrapeitoneal inoculation couldn‘t spread to the brain,suggesting blood-brain barrier could prevent the virus from spreading to the brain.     

Potential association of lead exposure during early development of mice with alteration of hippocampus nitric oxide levels and learning memory

Objective Chronic lead （Pb） exposure during development is known to produce learning deficits. Nitric oxide participates in the synaptic mechanisms involved in certain forms of learning and memory. This study was designed to clarify whether Pb-induced impairment in learning and memory was associated with the changes of nitric oxide levels in mice brains. Methods Sixty Balb/c mice aged l0 days were chosen. A model of lead exposure was established by drinking 0.025%, 0.05% 0.075% lead acetate, respectively for 8 weeks. The controls were orally given distilled water. The ability to learn and memorize was examined by open field test, T-water maze test. In parallel with the behavioral data, NO level of hippocampus tissue was detected by biochemical assay. Results Compared with control groups, （1） the weight of 0.075% group was significantly reduced （P〈0.05）; （2） The number of times in mice attaining the required standards in T-water maze test was lower in 0.075% group （P〈0.01）. No significant difference was found between experimental and control groups in open field test （P〉0.05）; （3） NO level of mouse hippocampus tissue was decreased in 0.075% group （P〈0.01）. Conclusions The findings suggest that decreased hippocampus NO level may contribute to the Pb-induced deficits in learning and memory processes.     

慢性脑缺血对大鼠认知功能障碍及影响机制研究

目的观察慢性脑缺血（CCH）过程中大鼠认知功能的变化、前额叶皮层和海马神经元组织学改变以及胆碱能系统改变,探讨慢性脑缺血致大鼠认知障碍的影响机制。方法选取大鼠分组后,应用Morris水迷宫定位航行实验和空间搜索实验观察各组大鼠学习记忆功能变化;苏木精-伊红染色观察前额叶皮层和海马组织学改变;免疫组织化学方法显示前额叶皮层和海马胆碱乙酰转移酶和烟碱型乙酰胆碱受体α4阳性细胞表达。结果①Morris水迷宫测试：a.定位航行实验：各组大鼠逃避潜伏期随天数增加而缩短,逃避潜伏期有差异性;b空间搜索实验：CCH各组大鼠在中环停留时间随低氧时间延长而减少;②与对照组比较,CCH大鼠前额叶皮层和海马变性坏死神经元增多,随着低氧时间延长而加重;③CCH各组大鼠前额叶皮层和海马ChAT阳性表达随低氧时间延长而下降;④CCH各组大鼠前额叶皮层和海马nAChRα4阳性表达随着低氧时间延长而下降。结论慢性脑缺血大鼠认知功能障碍随低氧时间延长呈加重趋势。慢性脑缺血致大鼠认知功能障碍的机制与大鼠前额叶皮层和海马神经元组织学改变和胆碱能系统改变有关。     

轴突生长抑制因子重组疫苗预防免疫减轻阿尔茨海默症模型小鼠行为学损伤

目的研究轴突生长抑制因子重组DNA疫苗对转基因阿尔茨海默症小鼠的预防治疗。方法轴突生长抑制因子重组DNA疫苗肌肉注射APP/PS1双转阿尔茨海默症模型小鼠。设野生对照组、模型对照组、空载体对照组、疫苗组。水迷宫实验检测小鼠行为学差别。结果疫苗组小鼠在4.5月龄水迷宫实验中学习记忆能力较模型对照及空载体对照组有显著差异(P<0.05)。结论肌肉注射轴突生长抑制因子DNA重组疫苗能够改善小鼠学习记忆能力。     

MCMV感染对小鼠海马胶质纤维酸性蛋白表达的影响

目的探讨小鼠巨细胞病毒感染对小鼠学习记忆及胶质纤维酸性蛋白(GFAP)表达的影响。方法采用颅内注射制造CMV颅内感染小鼠模型,利用Morris水迷宫试验对2组动物的学习和记忆成绩进行3 d测试,记录其成绩并观察海马组织GFAP表达水平的变化。结果 Morris水迷宫测试的结果显示,病毒感染组小鼠的学习记忆成绩明显下降,海马组织中GFAP的表达较对照组增高,差异有统计学意义(P0.01)。结论巨细胞病毒感染能够导致小鼠学习记忆能力下降,海马组织GFAP的表达明显增强。     

乌灵菌粉贯叶连翘复方制剂干预对慢性不可预知应激大鼠模型抗抑郁作用及机制的研究

目的观察乌灵菌粉贯叶连翘复方制剂对慢性不可预知应激大鼠行为学、下丘脑-垂体-肾上腺(HPA)轴功能以及海马组织单胺类神经递质含量的影响。方法选取SD大鼠72只,随机分为正常对照组、应激模型组、氟西汀组、乌灵菌粉贯叶连翘复方制剂(高、中、低剂量)组,给药28 d,实验结束时对各组大鼠进行糖水消耗实验、Morris水迷宫实验监测,采用放免法检测血清皮质酮(CORT)、促肾上腺皮质激素(ACTH)、促肾上腺皮质激素释放激素(CRH)的浓度,高效液相-电化学法检测海马中5-羟色胺(5-HT)、去甲肾上腺素(NE)以及多巴胺(DA)的含量。结果与正常对照组相比,模型组大鼠造模4周后,糖水偏嗜度明显降低,Morris水迷宫实验中大鼠逃避潜伏期延长、在目标象限的时间及总路程减少(P0.05);血液指标显示,模型组大鼠血清中的ACTH、CORT、CRH含量明显升高,海马组织单胺神经递质5-HT、NE和DA的含量明显降低(P0.05)。与模型组相比,乌灵菌粉贯叶连翘复方制剂490 mg/kg,245 mg/kg剂量组可显著升高模型组大鼠糖水偏嗜度,缩短大鼠逃避潜伏期,增加大鼠在目标象限的时间及总路程(P0.05,P0.01)。还可显著降低模型大鼠血清中ACTH、CORT、CRH含量,升高海马组织5-HT,NE和DA的含量(P0.05)。结论乌灵菌粉贯叶连翘复方制剂具有一定的抗抑郁作用,其机制可能与增加海马组织中5-HT、DA、NE的含量,改善应激刺激导致的HPA轴功能紊乱状态有关。     

5-羟色胺及其突触后1A受体对慢性应激大鼠情绪和认知的影响

目的:研究5-羟色胺(5-HT)及其突触后1A受体(5-HT1A)在应激适应中的作用.方法:使用对氯苯丙胺(p-PCA)将大鼠体内5-HT耗竭,并使用5-HT1A受体激动剂8-OH-DPAT及拮抗荆WAY100635,研究慢性应激、5-HT及其突触后5-HT1A受体等对大鼠在高架十字迷宫、强迫游泳和水迷宫测试中行为的影响.结果:应激后5-HT耗竭大鼠比正常大鼠在高架十字迷宫实验中开臂停留时间较少,闭臂停留时间较多;强迫游泳实验中不动时间较长;在水迷宫测试的第3,4天,逃离潜伏期明显增加,测试时在目标象限停留时间和穿越原平台位置次数明显减少.8-OH-DPAT能显著减少5-HT耗竭大鼠及5-HT耗竭应激大鼠焦虑和抑郁水平,上述作用则能被WAY100635阻断.在水迷宫实验中,8-OH-DPAT及WAY100635对大鼠找到平台的平均潜伏期、在目标象限的时间和穿越平台的次数无明显影响.结论:5-HT耗竭大鼠应激时更容易产生抑郁和焦虑症状,并易导致学习、记忆等认知功能受损,时应激适应能力下降.突触后5-HT1A的激活能够缓解5-HT耗竭及5-HT耗竭应激大鼠的焦虑和抑郁症状,促进对慢性应激的适应,但其对大鼠的学习记忆等认知功能无明显影响.     

H102-BD经鼻腔给药后对双转基因AD小鼠行为学及脑内APP和Aβ蛋白表达的影响

?目的:观察β片层阻断肽H102-BD经鼻腔给药后对PAP双转基因AD小鼠行为学、脑内APP及Aβ蛋白表达的影响。方法:将PAP转基因小鼠随机分为模型组和H102-BD给药组,并设同月龄同背景C57BL/6J小鼠为正常对照组。鼻腔给药4周后行Morris水迷宫实验,利用免疫组织化学方法和Western blot方法测定小鼠脑内APP和Aβ蛋白的表达。结果:（1）Morris水迷宫结果显示鼻腔给予H102-BD后AD模型鼠的空间记忆能力有了明显的提高。（2）免疫组化及Western blot结果显示,H102-BD可显著降低AD模型鼠脑内APP及Aβ蛋白表达。结论:β片层阻断肽H102-BD经鼻腔给药后对AD有一定的治疗作用。     

慢性脑缺血大鼠EphA4表达变化的研究

目的 探讨大鼠海马区及皮层EphA4表达在慢性脑缺血的不同时间点的动态变化.方法 大鼠随机分为正常组、假手术组、15 d、30 d和60 d模型组.采用双侧颈总动脉永久结扎建立慢性脑缺血模型:Morris水迷宫试验检测行为学变化:免疫组化染色检测EphA4的表达变化.结果 EphA4免疫反应阳性细胞数模型组比假手术组均增多(P<0.05>,与行为学改善基本相符.结论 慢性脑缺血造成EphA4表达持续升高可能是成年哺乳动物损伤后神经再生障碍的重要原因之一.     

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.     

Cyanidin-3-O-galactoside and Blueberry Extracts Supplementation Improves Spatial Memory and Regulates Hippocampal ERK Expression in Senescence-accelerated Mice

Objective To investigate whether the antioxidation and the regulation on the Extracellular Regulated Protein Kinases(ERK) signaling pathway are involved in the protective effects of blueberry on central nervous system. Methods 30 Senescence-accelerated mice prone 8(SAMP8) mice were divided into three groups and treated with normal diet, blueberry extracts(200 mg/kg·bw/day) and cyaniding-3-O-galactoside(Cy-3-GAL)(50 mg/kg·bw/day) from blueberry for 8 weeks. 10 SAMR1 mice were set as control group. The capacity of spatial memory was assessed by Passive avoidance task and Morris water maze. Histological analyses on hippocampus were completed. Malondialdehyde(MDA) levels, Superoxide Dismutase(SOD) activity and the expression of ERK were detected. Results Both Cy-3-GAL and blueberry extracts were shown effective functions to relieve cellular injury, improve hippocampal neurons survival and inhibit the pyramidal cell layer damage. Cy-3-GAL and blueberry extracts also increased SOD activity and reduced MDA content in brain tissues and plasma, and increased hippocampal phosphorylated ERK(p-ERK) expression in SAMP8 mice. Further more, the passive avoidance task test showed that both the latency time and the number of errors were improved by Cy-3-GAL treatment, and the Morris Water Maze test showed significant decreases of latency were detected by Cy-3-GAL and blueberry extracts treatment on day 4. Conclusion Blueberry extracts may reverse the declines of cognitive and behavioral function in the ageing process through several pathways, including enhancing the capacity of antioxidation, altering stress signaling. Cy-3-GAL may be an important active ingredient for these biological effects.     

单侧穹窿伞损伤对老年大鼠空间记忆及海马胆碱能纤维的影响

对老年大鼠行单侧穹窿伞横断术，术后２周，用Ｍｏｒｒｉｓ水迷宫试验及乙酰胆碱酯酶（ＡｃｈＥ）染色观察大鼠的学习记忆及海马ＡｃｈＥ阳性纤维密度的变化。结果表明：海马ＣＡ１、ＣＡ３及齿状回的ＡｃｈＥ纤维明显减少，而且减少程度与学习记忆的下降成正相关关系。说明该模型既具有老年性痴呆的主要临床表现──学习记忆下降，另一部分模拟了该病的主要神经病理改变──基底前脑的胆碱能纤维溃变。