Multifaceted neuroprotective effects of(-)-epigallocatechin-3-gallate(EGCG)in Alzheimer's disease:an overview of pre-clinical studies focused onβ-amyloid peptide

Alzheimer’s disease(AD)is the most common neurodegenerative disease characterized by cognitive decline and memory impairment.Many lines of evidence indicate that excessiveβ-amyloid peptide(Aβ)generation and aggregation play pivotal roles in the initiation of AD,leading to various biochemical alteration including oxidative damage,mitochondrial dysfunction,neuroinflammation,signaling pathway and finally resulting in neuronal death.AD has a complex pathogenic mechanism,and a single-target approach for anti-AD strategy is thus full of challenges.To overcome these limitations,the present study focused to review on one of multiple target-compounds,(-)-epigallocatechin-3-gallate(EGCG)for the prevention and treatment of AD.EGCG is a main bioactive polyphenol in green tea and has been reported to exert potent neuroprotective properties in a wide array of both cellular and animal models in AD.This review demonstrated multiple neuroprotective efficacies of EGCG by focusing on the involvement of Aβ-evoked damage and its Aβregulation.Furthermore,to understand its mechanism of action on the brain,the permeability of the blood-brain barrier was also discussed.

Protective effects of proanthocyanidins on beta-amyloid peptide (25-35)-induced PC12 cell apoptosis by blocking S-phase and increasing p53 gene expression

BACKGROUND： Current studies related to the effects of proanthocyanidins on Alzheimer＇s disease have focused primarily on the signal transduction pathway of cellular apoptosis. However, the influence of p53 gene expression on cell cycle regulation, with regard to the protective mechanisms of proanthocyanidins, has not been reported. OBJECTIVE： To observe the effect of proanthocyanidins on cell cycle distribution, cellular apoptosis and p53 gene expression in β-amyloid peptide （25-35） （Aβ25-35）-induced PC12 cells cultured in serum-free media, and to investigate the molecular neuroprotective mechanisms of proanthocyanidins with regard to cell cycle regulation. DESIGN, TIME AND SETTING： A parallel, controlled, at the Institute of Biochemistry and Molecular Biology cellular, and molecular study was performed Guangdong Medical College from July 2006 to July 2008. MATERIALS： Proanthocyanidins were provided by Nanjing Xuezi Medical and Chemical Research Center, China; Aβ25-35 was provided by Sigma, USA; PC12 cells were provided by the Institute of Basic Medical Science, Academy of Military Medical Sciences; and rabbit anti-p53 polyclonal antibody was provided by Santa Cruz Biotechnology, USA. METHODS： PC12 cells were cultured in serum-free media for 24 hours. Cells from the model group were treated with 25 μmol/L Aβ25-35 for 24 hours. Cells in the drug protection group were pre-treated with 30 mg/L proanthocyanidins for 1 hour and then treated with 25 μmol/LAβ2^-35 for 24 hours. The control group was not treated. MAIN OUTCOME MEASURES： Flow cytometry was used to detect cell cycle distribution and rate of apoptosis; reverse-transcriptase polymerase chain reaction was used to detect p53 mRNA expression; and Western blot was used to detect p53 protein expression. RESULTS： After treating with 25 μmol/LAβ25-35 for 24 hours, the rate of apoptosis and the percentage of cells in S phase were significantly increased （P 〈 0.01 ）, and p53 mRNA and protein expressions were decreased. Pretreatment with proanthocyanidins for 1 hour blocked the increase in apoptosis and the percentage of cells in S phase in Aβ25-35-induced PC12 cells （P 〈 0.01 ） and increased p53 mRNA and protein expressions. CONCLUSION： Proanthocyanidins blocked apoptosis and S-phase arrest in Aβ25-35-induced PC12 cells cultured in serum-free media. The protective mechanism could be related to increased p53 mRNA and protein expressions.

Hydrogen sulfide inhibits beta-amyloid peptide-induced apoptosis in PC12 cells and the underlying mechanisms

BACKGROUND：Studies have demonstrated that hydrogen sulfide（H2S） levels are 55% lower in brains of Alzheimer＇s disease（AD） patients than in age-matched normal individuals,which suggests that H2S might be involved in some aspects of AD pathogenesis.OBJECTIVE：To observe the protective mechanisms of varied concentrations of H2S against β-amyloid-peptide（Aβ） induced apoptosis in pheochromoytoma（PC12） cells,and to analyze the pathway of action.DESIGN,TIME AND SETTING：A controlled,observational,in vitro experiment was performed at Neurophysiology Laboratory in Zhongshan Medical School,Sun Yat-sen University between July 2006 and May 2007.MATERIALS：PC12 cells were provided by the Animal Experimental Center of Medical School of Sun Yat-sen University.Glybenclamide,rhodamine123,and dihydrorhodamine123 were purchased from Sigma（USA）.METHODS：PC12 cells were incubated at 37 ℃ in a 5% CO2-enriched incubator with RPMI-1640 medium,supplemented with 5% horse-serum and 10% fetal bovine serum.Cells in logarithmic growth curves received different treatment：The PC12 cells were maintains at 37 ℃ with the original medium,then incubated in Aβ25-35,sodium hydrosulfide（NaHS）,glybenclamide,NaHS＋ Aβ25-35,or pretreated with glybenclamide 30 minutes prior to administration of and Aβ25-35,respectively.MAIN OUTCOME MEASURES：（1） The survival rate of PC12 cells was detected by MTT assay and Hoechst staining.（2） The apoptosis rate of PC12 cells was detected utilizing flow cytometry with propidium iodide staining,and morphological changes of apoptotic cells were observed.（3） The mitochondrial membrane potential was detected by Rhodamine123-combined flow cytometry.（4） The intracellular reactive oxygen species content was detected by dihydrorhodamine123-combined flow cytometry.RESULTS：Aβ25-35 induced significantly decreased viability and increased percentage of apoptosis in PC12 cells,as well as dissipated mitochondrial membrane potential expression and an overproduction of reactive oxygen species.When PC12 cells were co-treated with NaHS and Aβ25-35,the decreased cell viability induced by 20 μmol/L Aβ25-35 was concentration-dependently blocked by NaHS（50,100,and 200 μmol/L）.NaHS（100 μmol/L） obviously reduced the percentage of apoptotic PC12 cells induced by 20 μmol/L Aβ25-35.In addition,100 μmol/L NaHS inhibited mitochondrial membrane potential dissipation and reactive oxygen species overproduction.When the ATP-sensitive K channel（KATP） inhibitor,glybenclamide,was administered 30 minutes prior to NaHS and Aβ25-35 treatment,the NaHS-dependent cellular protection was partly blocked.This resulted in reduced PC12 cell viability and increased the percentage of apoptosis,as well as significantly blocked mitochondrial membrane potential preservation and inhibited reactive oxygen species overproduction due to NaHS treatment.CONCLUSION：NaHS protected PC12 cells against Aβ25-35-induced damage.NaHS-dependent cellular protection was associated with mitochondrial membrane potential preservation and inhibition of reactive oxygen species overproduction.The KATP channel inhibitor,glybenclamide,significantly blocked the cellular protective effects of NaHS,indicating that KATP channel activation plays an important role in NaHS-induced protection of PC12 cells to Aβ25-35-induced damage.

Effects of Yizhi Capsule (益智胶囊) on Learning and Memory Disorder and β-amyloid Peptide Induced Neurotoxicity in Rats

To explore the effects of Yizhi Capsule （益智胶囊, YZC） on learning and memory disorder and β-amyloid peptide induced neurotoxicity in rats. Methods： Various doses of YZC were administered to Sprague-Dawley （SD） rats for 8 consecutive days, twice a day. On the 8th day of the experiment, scopolamine hydrobromide was intraperitoneally injected to every rat and Morris water maze test and shuttle dark avoidance test were carried out respectively to explore the changes of learning and memory capacities in the rats. Resides, after the cerebral cortical neurons of newborn SD rats aged within 3 days were cultured in vitro for 7 days, drug serum containing YZC was added to the cultured neurons before or after β amyloid peptide25-35 （Aβ25-35） intoxication to observe the protective effect of YZC on neurotoxicity by MTT assay and to determine the LDH content in the supernatant. Results： Compared with those untreated with YZC, the rats having received YZC treatment got superiority in shorter time of platform seeking in Morris water maze test, as well as elongated latent period and less times of error in shuttle dark avoidance test. On the cultured neurons, YZC drug serum could effectively increase the survival rate of Aβ25-35 intoxicated neurons and reduce the LDH contents in cultured supernatant. Conclusion： YZC has an action of improving learning and memory disorder, and good protective effect on Aβ25-35 induced neurotoxicity in SD rats. KEY WORDS

STUDY ON THE THERAPEUTIC EFFECTS OF GINSENOSIDE Rg-1 AND GASTRODINE ON AD MODEL RATS INDUCED BY β-AMYLOID PEPTIDE (25-35)

Objective To study the therapeutic effects of Ginsenoside Rg-1 and Gastrodine on rats model of Alzheimer's disease(AD). Methods Aggregated β-Amyloid peptide (25-35) was injected into the lateral ventricle of rats to establish AD models. Ginsenoside Rg-1, Gastrodine and Ginsenoside Rg-1+Gastrodine were intraperitoneally injected into rats of each test group(Ginsenoside Rg-1∶10mg/kg·day; Gastrodine 100mg/kg·day) for 4 weeks, the rats of control group received equal volume of saline. Passive avoidance task and Morris maze test were done to assess the ability of learning and memory. The content of superoxide dismutase (SOD), malondiadehyde (MDA), total-antioxidative capability (T-AOC), Choline acetyltransferase (ChAT) and acetylcholinesterase (AchE) in brain tissue were measured. Results Ginsenoside Rg-1 and Gastrodine significantly improved learning and memory deficits in the rats with AD induced by β-Amyloid peptide (25-35) (P<0.05). Ginsenoside Rg-1+Gastrodine group were better than Ginsenoside Rg-1 group and Gastrodine group (P<0.05). Ginsenoside Rg-1 reduced the increase of SOD, MDA, but inhibited the decrease of T-AOC, AchE and ChAT; Gastrodine reduced the increase of SOD, MDA, while inhibited the decrease of T-AOC. Gastrodine could also prevent the activity of ChAT and AchE decline in AD rats. Conclusion Both Ginsenoside Rg-1 and Gastrodine have therapeutic effects on rats with AD; Ginsenoside Rg-1 and Gastrodine injection at the same time were better than only using one of them. Their mechanisms might different. Ginsenoside Rg-1 can not only inhibit peroxidation but also increase the activity of AchE and ChAT in brain tissue, while Gastrodine can inhibit peroxidation only, but it can't prevent the decline of ChAT and AchE activity in AD rats.

针刺公孙、四缝穴配合脏腑点穴对胃肠结热型小儿肠系膜淋巴结炎的疗效观察

目的分析针刺公孙、四缝穴配合脏腑点穴对小儿肠系膜淋巴结炎(胃肠结热型)的疗效以及对血清肠型脂肪酸结合蛋白(I-FABP)、血管活性肠肽(VIP)的影响。方法选择肠系膜淋巴结炎(胃肠结热型)患儿60例为研究对象,根据随机数字表法分为对照组(n=30,予常规治疗+针刺公孙、四缝穴)与研究组(n=30,在对照组基础上配合使用脏腑点穴)。比较2组临床疗效、主要症状与体征变化,并检测血清I-FABP、VIP表达水平。结果研究组治疗总有效率高于对照组,差异有统计学意义(P<0.05)。治疗2周后,2组血清I-FABP水平较治疗前降低,且研究组血清I-FABP水平低于对照组,差异有统计学意义(P<0.05);治疗2周后,2组血清VIP水平较治疗前升高,且研究组血清VIP水平高于对照组,差异有统计学意义(P<0.05)。治疗2周后,研究组主要症状与体征改善程度优于对照组,差异有统计学意义(P<0.05)。结论针刺公孙、四缝穴配合脏腑点穴可用于治疗胃肠结热型小儿肠系膜淋巴结炎,能够调理和改善胃肠道功能,调节血清I-FABP、VI水平,缓解患儿主要症状与体征,临床可作为一种有效的治疗方法。

Brain-derived neurotrophic factor prevents beta-amyloid-induced apoptosis of pheochromocytoma cells by regulating Bax/Bcl-2 expression

Brain-derived neurotrophic factor was utilized in the present study to treat cell injury models induced by aggregated β-amyloid（25 35）. Methylthiazolyldiphenyl-tetrazolium bromide assay and western blot analysis showed that brain-derived neurotrophic factor provided neuroprotection against cellular apoptosis by suppressing the decline in β-amyloid（25 35）-induced cell activity and the increasing ratio of Bax/Bcl-2. After treating pheochromocytoma cells with tyrosine kinase receptor B receptor inhibitor K252a, brain-derived neurotrophic factor reverses the above- mentioned changes. The experimental findings suggested that brain-derived neurotrophic factor prevented β-amyloid peptide-induced cellular apoptosis by modulating Bax/Bcl-2 expression, and this effect was associated with binding to the specific tyrosine kinase receptor B receptor.

<i>Ratanasampil</i>(Tibetan Medicine, RNSP) Reduces <i>β</i>-Amyloid Protein (Aβ) and Pro-Inflammatory Factor Levels and Improves Cognitive Functions in Mild-to-Moderate Alzheimer’s Disease (AD) Patients Living at High Altitude

Ratanasampil (RNSP) is a traditional Tibetan medicine used for the treatment of stroke and cerebrovascular diseases. Previous discoveries that RNSP can reduce β-amyloid protein levels and increase learning and memory in Alzheimer’s mouse models (Tg2576) led us to investigate whether RNSP can improve cognitive functions in Alzheimer’s patients. In this study, 146 AD patients living in Qinghai province received either one gram or 0.33 gram daily of RNSP for 16 weeks. Placebo patients received Piracetam. Serum Aβ40 and Aβ42 levels were measured at the beginning of the study and after 4 and 16 weeks of treatment. Compared to the same group before treatment, MMSE scores, ADAS-cog scores and ADL scores were significantly improved (p 0.05, p > 0.05). After 16-week treatment, serum TNF-α, IL-1β, IL-6 and Aβ42 levels were significantly decreased (p < 0. 01) in the high-dose RNSP group, whereas no significant differences were found in the low-dose and placebo groups. The Aβ42/Aβ40 ratio was significantly decreased after 4-week and 16-week treatment in the high-dose RNSP group (p < 0. 05, p < 0.01). Furthermore, serum Aβ42 concentrations had a strong positive correlation with TNF-α, IL-1β and IL-6 levels. There were no observable adverse effects in either treatment or control groups. We conclude that further clinical trials of RNSP in Alzheimer disease are warranted.

中药调控小胶质细胞改善阿尔茨海默病的研究进展

小胶质细胞(microglia,MG)作为中枢神经系统的主要免疫巨噬细胞,可通过不同极化状态和受体蛋白表达水平参与阿尔茨海默病(Alzheimer′s disease,AD)的发生、发展过程。传统中药对小胶质细胞具有调控作用,中药所含多种成分在减少淀粉样蛋白(amyloidβ-protein,Aβ)沉积、抑制神经炎症以及调控MG极化等方面可发挥重要作用。该文对MG在AD发病机制中的作用以及中药调控MG的作用和机制进行总结和分析,旨在为中药治疗AD提供参考。

黄葵敛肠汤保留灌肠治疗溃疡性结肠湿热内蕴证临床研究

目的探讨黄葵敛肠汤保留灌肠治疗溃疡性结肠炎(UC)湿热内蕴证的临床疗效,以及对患者脑肠肽及免疫功能指标的影响。方法选取医院2020年7月至2021年6月收治的UC湿热内蕴证患者120例,随机分为观察组和对照组,各60例。对照组患者给予美沙拉嗪肠溶片口服治疗,观察组患者给予黄葵敛肠汤保留灌肠治疗,两组患者均治疗12周。结果观察组总有效率为83.33%,显著高于对照组的73.33%(P<0.05)。治疗后,观察组主要症状腹泻、腹痛、黏液血便、里急后重评分均显著低于对照组(P<0.05);Baron内镜评分及梅奥(Mayo)评分均显著低于对照组(P<0.05);脑肠肽指标血清5-羟色胺(5-HT)和血浆P物质(SP)含量均显著低于对照组,血清生长抑制(SS)水平和血浆血管活性肠肽(VIP)含量均显著高于对照组(P<0.05);血清免疫球蛋白(Ig)A、IgG水平均显著低于对照组(P<0.05)。观察组患者不良反应发生率为6.67%,显著低于对照组的15.00%(P<0.05)。结论黄葵敛肠汤保留灌肠治疗UC湿热内蕴证疗效佳,可抑制患者的肠黏膜炎性反应,减轻黏膜损伤,且安全性好。

Specific humoral immune responses in rhesus monkeys vaccinated with the Alzheimer’s disease-associated β-amyloid 1-15 peptide vaccine

Background Alzheimer’s disease(AD) is a neurodegenerative disorder characterized by overproduction of β-amyloid (Aβ), with the subsequent pathologic deposition of Aβ which is important for memory and cognition. Recent studies showed murine models of AD and AD patients inoculated with Aβ 1-42 peptide vaccine had a halted or delayed pathological progression of AD. Unfortunately, the clinical phase Ⅱ a trial of Aβ 1-42 peptide vaccine (AN1792) was halted prematurely because of episodes of menigoencephalitis in 18 of the vaccinated patients. The vaccination of BALB/c or Tg2576 transgenic mouse with Aβ 1-15 peptide vaccine is safe and the immune effects are satisfactory. This study further characterizes the specific humoral immune responses in adult rhesus monkeys induced by Aβ 1-15 peptide vaccine.Methods Five male adult rhesus monkeys were injected intramuscularly with Aβ 1-15 peptide vaccine at baseline and at weeks 2, 6, 10, 14, 18 and 22. The titers and IgG isotypes of the antibody against Aβ 1-42 in serum was measured by Enzyme-linked Immunosorbent Assay (ELISA). The specificity of the antibody against Aβ 1-42 was determined by Western blot. The Aβ plaques in Tg2576 transgenic mouse brain were stained with the antiserum using immunohistochemistry method.Results At the eighth week after the vaccination, antibody against Aβ 1-42 began to develop significantly in serum. The titers of the antibody increased following vaccine boosted and reached 1∶3840 at the twenty-fourth week, then decreased after the termination of inoculation. The IgG1 was accounted for the highest level in the antiserum pool. The antibody against Aβ 1-42 showed high specificity. The Aβ plaques in Tg2576 transgenic mouse brain were labeled with the antiserum.Conclusion Aβ 1-15 vaccine can induce vigorously specific humoral immune responses in adult rhesus monkey.

P3肽抑制RAW264.7巨噬细胞泡沫化的分子机制

目的观察P3肽对RAW264.7巨噬细胞脂质沉积的影响,并探讨其作用机制。方法采用MTT法筛选P3肽及氧化低密度脂蛋白(oxidized low density lipoprotein,ox-LDL)的作用浓度,并用80 mg·L^(-1)的ox-LDL诱导RAW264.7细胞形成泡沫细胞;分别采用油红O染色和总胆固醇含量测定试剂盒,检测细胞内脂质沉积及总胆固醇含量;实时荧光定量PCR(quantitative real-time PCR,qRT-PCR)及Western blot检测三磷酸腺苷结合盒转运体A1(ATP-binding cassette transporter A1,ABCA1)、三磷酸腺苷结合盒转运体G1(ATP-binding cassette transporter G1,ABCG1)的mRNA和蛋白表达变化;分别应用肝X受体(liver X receptor,LXR)的激动剂T0901317、GW3965,以及LXR抑制剂GSK2033进一步验证P3肽调控ABCA1、ABCG1表达的作用机制。结果P3肽明显减少RAW264.7细胞内脂质沉积,降低细胞内总胆固醇含量,上调ABCA1、ABCG1mRNA和蛋白表达;P3肽上调ABCA1、ABCG1的作用与LXR激动剂T0901317、GW3965相似;加入抑制LXR基因转录的抑制剂GSK2033后,P3肽对ABCA1、ABCG1的基因表达无上调作用。结论P3肽可减少RAW264.7巨噬细胞内脂质积聚,抑制泡沫细胞的形成,其作用机制可能与激活LXR-ABCA1/ABCG1通路有关。

Determination of β-amyloid peptides in vitro aggregation process by electrochemistry

An impedimetric sensor(EA/mAb/CeZnO/GCE)for detecting β-amyloid peptides(Aβ)was successfully constructed by synthesizing ceria doped zinc oxide(CeZnO)nanoparticles to modify the glassy carbon electrode(GCE)for immobilizing the antibody mAb,and blocking the unbound carboxyl sites with ethanolamine(EA).The sensor exhibited a linear detection range of 10–100 pM and a detection limit of 1.7 pM(S/N=3),and the relative standard deviations(RSDs)of the inter-electrode and intra-electrodes were less than 3.0%.After it was stored at 4℃ for 2 d,its impedance value was 101.6% of original impedance response.The sensor was used to measure the remaining content of Aβ incubated in vitro.The results showed that after incubation for 48 h and 60 h,the content of aggregated Aβ(oligomers and fibers)almost unchanged,reaching about 90%.This method had the advantages of time-saving,simple procedure,economical,excellent conductivity,good reproducibility and stability.

Cholesterol Depletion Reduces the Internalization of β-Amyloid Peptide in SH-SY5Y Cells

Deposition of amyloid in the brain is a critical step in the pathogenesis of Alzheimer＇s disease. The endocytosis of β-amyloid peptide （Aβ） is an important factor among the many factors that contribute to the genesis of amyloid deposits. Since cholesterol participates in many important physiological processes, the present work investigated the relationship between the cellular cholesterol content and the endocytosis of the exogenic Aβ, and found that reduction of the cholesterol content by methyl-β-cyclodextrin could reduce the endocytosis of AI3. The study indicates that the endocytosis of Aβ is partly mediated by cholesterol.

真武汤加味结合常规疗法治疗阳虚水泛型慢性心力衰竭临床研究

目的观察真武汤加味治疗阳虚水泛型慢性心力衰竭(CHF)的临床疗效。方法将60例CHF患者随机分为治疗组与对照组,各30例;对照组采用西医常规治疗,治疗组采用西医常规结合真武汤加味治疗,疗程14天。观察两组临床疗效、证候积分、彩色超声心动图指标、脑钠肽(BNP)变化。结果治疗组的临床疗效优于对照组(P<0.05);治疗后两组左室射血分数(LVEF)、每搏输出量(SV)、左室舒张末期容积(LVEDV)、左室收缩末期容积(LVESV)均有明显改善(P<0.05,P<0.01),且治疗组的改善优于对照组(P<0.05);治疗后两组血浆BNP水平显著降低(P<0.01),且治疗组低于对照组(P<0.05)。结论真武汤加味可以改善慢性心力衰竭患者心脏功能、降低BNP水平。

软肝化纤汤联合恩替卡韦治疗慢性乙型肝炎后肝纤维化(肝郁脾虚)随机平行对照研究

[目的]观察软肝化纤汤联合恩替卡韦治疗慢性乙型肝炎后肝纤维化(肝郁脾虚)疗效。[方法]使用随机平行对照方法,将112例门诊患者按就诊顺序号方法随机分为两组。对照组56例恩替卡韦,0.5mg/次,1次/d,视耐受、年龄、病情等酌情调整剂量。治疗组56例软肝化纤汤(甘草炙6g,片姜黄、三七、龙葵、郁金、柴胡醋各10g,绞股蓝、赤芍、白花蛇舌草各15g,丹参、党参各20g,鳖甲30g),1剂/d,水煎400mL,早晚口服;恩替卡韦治疗同对照组。连续治疗6个月为1疗程。观测临床表现、血清白蛋白(ALB)、天门冬氨酸氨基转移酶(AST)、丙氨酸氨基转移酶(ALT)、总胆红素(TBiL)、Ⅲ型前胶原肽(PⅢP)、Ⅳ型胶原(Ⅳ-C)、层黏连蛋白(LN)、透明质酸(HA)、不良反应。治疗1疗程(6个月),判定疗效。[结果]ALB、AST、ALT、TBiL两组均有改善(P<0.01),AST、ALT、TBiL治疗组改善优于对照组(P<0.01),ALB两组间无明显差异(P>0.05)。PⅢP、Ⅳ-C、LN、HA两组均有改善(P<0.01),治疗组改善优于对照组(P<0.01)。[结论]软肝化纤汤联合恩替卡韦慢性乙型肝炎后肝纤维化(肝郁脾虚),疗效满意,无严重不良反应,值得推广。

Notoginseng Saponin Rg1 Prevents Cognitive Impairment through Modulating APP Processing in Aβ1-42-injected Rats

With the intensification of the aging process of the world,Alzheimer's disease(AD),which is the main type of senile dementia,has become a primary problem in the present society.Lots of strategies have been used to prevent and treat AD in animal nlodels and clinical trials,but most of them ended in failure.Panax notoginseng saponins(PNS)contain a variety of monomer compositions which have been separated and identified.Among of the monomer compositions,notoginseng saponin Rg1(Rg1)accounts for 20%of the cultivation of panax notoginseng roots.And now PNS have been reported to be widely used to treat cardicerebrovascular diseases and have neuroprotective effects to restrain theβ-amyloid peptide(Aβ)25-35-niediated apoptosis.Moreover,it is reported that PNS could accelerate the growth of nerve cells,increase the length of axons and promote synaptic plasticity.Whether Rg1 can ameliorate the cognitive impairment and the underlying mechanism has not been elucidated.To study the preventive effect of Rg1 on cognitive impairment and the possible mechanism,we established the cognitive impairment model in rats through Aβ1-42(2.6μg/μL,5μL)injection and then treated the rats with Rg1(25,50 and 100 mg/kg)administered intragastrically for 4 weeks.We observed that Aβ1-42 could induce spatial learning and memory deficits in rats.Simultaneously,Aβ1-42 injection also resulted in the reduced neuron number in comuammonis 1(CA1)and dentate gyrus(DG)of hippocampus,as well as the increased level of hyperphosphorylatedβ-amyloid precursor protein(APP)at Thr668 site with up-regulation ofβ-APP cleaving enzyme 1(BACE1)and presenilin 1(PS1)and down-regulation of a disintegrin and metalloprotease domain-containing protein 10(ADAM 10)and insulindegrading enzyme(IDE).Administration of Rg1 effectively rescued the cognitive impairment and neuronal loss,and inhibited theβ-secretase processing of APP through reducing APP-Thr668 phosphorylation and BACE1/PS1 expression,and increasing the expression of ADAM 10 and IDE.We concluded that Rg1 might have neuroprotective effects and could promote learning and memory ability,which might be a viable candidate in AD therapy probably through reducing the generation of Aβand increasing the degradation of Aβ.

Osthole improves synaptic plasticity in the hippocampus and cognitive function of Alzheimer's disease rats via regulating glutamate

Osthole, an effective monomer in Chinese medicinal herbs, can cross the blood-brain barrier and protect against brain injury, with few toxic effects. In this study, a rat model of Alzheimer＇s disease was established after intracerebroventricular injection of β-amyloid peptide （25-35）. Subsequently the rats were intraperitoneally treated with osthole （12.5 or 25.0 mg/kg） for 14 successive days. Results showed that osthole treatment significantly improved cognitive impairment and protected hippocampal neurons of AIzheimer＇s disease rats. Also, osthole treatment alleviated suppressed long-term potentiation in the hippocampus of Alzheimer＇s disease rats. In these osthole-treated Alzheimer＇s disease rats, the level of glutamate decreased, but there was no significant change in y-amino-butyric acid. These experimental findings suggest that osthole can improve learning and memory impairment, and increase synaptic plasticity in Alzheimer＇s disease rats. These effects of osthole may be because of its regulation of central glutamate and y-amino-butyric acid levels.

Otophylloside B Protects Against AβToxicity in Caenorhabditis elegans Models of Alzheimer’s Disease

Alzheimer’s disease(AD)is a major public health concern worldwide and the few drugs currently available only treat the symptoms.Hence,there is a strong need to find more effective anti-AD agents.Cynanchum otophyllum is a traditional Chinese medicine for treating epilepsy,and otophylloside B(Ot B),isolated from C.otophyllum,is the essential active component.Having previously identified anti-aging effects of Ot B,we evaluated Ot B for AD prevention in C.elegant models of AD and found that Ot B extended lifespan,increased heat stress-resistance,delayed body paralysis,and increased the chemotaxis response.Collectively,these results indicated thatOt B protects against Aβtoxicity.Further mechanistic studies revealed that Ot B decreased Aβdeposition by decreasing the expression of Aβat the mRNA level.Genetic analyses showed that Ot B mediated its effects by increasing the activity of heat shock transcription factor(HSF)by upregulating the expression of hsf-1 and its target genes,hsp-12.6,hsp-16.2 and hsp-70.Ot B also increased the expression of sod-3 by partially activating DAF-16,while SKN-1 was not essential in Ot B-mediated protection against Aβtoxicity.

Activation of α7 nAChR by PNU improves synaptic and cognitive function through restoring the expression of synaptic-associated proteins

OBJECTIVE Alzheimer disease(AD) is the most common type of dementia and is featured by the accumulation of β-amyloid peptide(Aβ) in the brain. The Alpha 7 nicotinic acetylcholine receptor family(α7 nAChR) was widely considered to interact with that Aβ, mediate neuroprotection and improve cognitive performance. However, the mechanisms underlying these interactions remain elusive. The present study aimed to determine how this interaction contribute to AD pathology. METHODS In vitro model of AD(primary culture of mice hippocampus treated with Aβ) and in vivo, a mouse model of AD(APPswe/PSEN1 d E9 double transgenic mice, APP/PS1_DT mice) were used to study to the possible inter-action of α7 nAChR and Aβ in the pathogenesis of AD. In vitro experiments, the primary hippocampal neurons cell was exposed to Aβ1-42 peptides in combination with PNU. In vivo experiments, different drugs/operations was applied to APP/PS1_DT mice for setting up of the following groups: WP group, wild-type C57 mice treated with PNU(α7 nAChR specific agonist);AP group, APP/PS1_DT mice treated with PNU;APP/PS1 group, the APP/PS1_DT mice injected intraperitoneally with the same amount of normal saline for 5 d;Control group, wild-type C57 mice injected intraperitoneally with the same amount of normal saline for 5 d. A transmission electron microscope was used to observed the synaptic morphological changes of hippocampal neurons. Reverse transcription quantitative PCR(RT-q PCR) and Western blot analysis were used to detect the expression levels of synaptic-associated proteins(SYN, SNAP25 etc). The learning and memory abilities of mice were detected by Morris water maze. RESULTS In vitro, it was found that α7 nAChR acts as an anti-Aβ-induced synaptic injury to nerve cell by increased the expression of synaptic-associated proteins and attenuated apoptosis induced by Aβ oligomers. In vivo, α7 nAChR attenuated synaptic loss induced by Aβ1-42, reduced the deposition of Aβ1-42 in the hippocampus and maintained the integrity of synaptic structures in the hippocampus. Furthermore, in the Morris water maze test, α7 nAChR improved the learning and memory ability of the APP/PS1_DT mice. CONCLUSION Theα7 nAChR attenuate the toxic effect of Aβ in vivo and in vitro, eg reduced the deposition of Aβ in the hippocampus,prevented the synaptic loss, partially restored the expression levels of synaptic-associated proteins, and improved the learning and memory abilities of APP/PS1_DT mice. Our results also suggested that the α7 nAChR interacted with Aβby mediated by Ca M-Ca MKⅡ-CREB signalling pathway, which was imbalanced by deposition of Aβ.