钩藤散改善APP/PS1双转基因小鼠学习记忆功能的代谢组学研究

目的:采用非靶向的高通量尿液代谢组学技术对钩藤散改善淀粉样前体蛋白/早老素蛋白1基因,即APP/PS1双转基因小鼠的作用机制进行研究。方法:5月龄APP/PSI小鼠采用Morris水迷宫实验检测双转基因小鼠的空间学习能力,在确定出现空间记忆能力功能损伤地条件下采用基于非靶向的尿液代谢组学技术研究APP/PSI小鼠的代谢网络,聚焦关键通路,同时观察钩藤散在水迷宫和代谢水平上的治疗作用。结果:Morris水迷宫对比发现APP/PSI小鼠的空间记忆能力明显长于同窝野生小鼠,给予钩藤散后呈现一定程度的回调趋势,经非靶向的代谢轮廓分析和核心代谢通路聚焦后,成功发现正常小鼠(同窝野生小鼠)和APP/PSI双转基因小鼠代谢轮廓间差异最大的信号,经质谱解析和权威数据库检索后鉴定6个与学习记忆相关的潜在生物标记物,分别是牛磺酸(taurine)、叶酸(pteroylglutamic acid)、新蝶呤(neopterin)、磺乙谷酰胺(glutaurine)、戊邻酮二酸盐(2-oxoglutarate)、二氢新蝶呤(dihydroneopterin),他们主要涉及牛磺酸代谢及叶酸代谢等,经钩藤散治疗后能有效回调。结论:钩藤散对APP/PSI双转基因小鼠的学习记忆能力具有一定治疗作用,本次发现的6个生物标记物可能是APP/PSI双转基因小鼠发病的潜在靶点,为钩藤散的相关药效学研究提供实验依据。     

Isoflurane Exposure during Mid-Adulthood Attenuates Age-Related Spatial Memory Impairment in APP/PS1 Transgenic Mice

Many in vitro findings suggest that isoflurane exposure might accelerate the process of Alzheimer Disease (AD); however, no behavioral evidence exists to support this theory. In the present study, we hypothesized that exposure of APP/PS1 transgenic mice to isoflurane during mid-adulthood, which is the pre-symptomatic phase of amyloid beta (Abeta) deposition, would alter the progression of AD. Seven-month-old Tg(APPswe,PSEN1dE9)85Dbo/J transgenic mice and their wild-type littermates were exposed to 1.1% isoflurane for 2 hours per day for 5 days. Learning and memory ability was tested 48 hours and 5 months following isoflurane exposure using the Morris Water Maze and Y maze, respectively. Abeta deposition and oligomers in the hippocampus were measured by immunohistochemistry or Elisa 5 months following isoflurane exposure. We found that the performance of both the transgenic and wild-type mice in the Morris Water Maze significantly improved 48 hours following isoflurane exposure. The transgenic mice made significantly fewer discrimination errors in the Y maze following isoflurane exposure, and no differences were found between wild-type littermates 5 months following isoflurane exposure. For the transgenic mice, the Abeta plaque and oligomers in the hippocampus was significantly decreased in the 5 months following isoflurane exposure. In summary, repeated isoflurane exposure during the pre-symptomatic phase not only improved spatial memory in both the APP/PS1 transgenic and wild-type mice shortly after the exposure but also prevented age-related decline in learning and memory and attenuated the Abeta plaque and oligomers in the hippocampus of transgenic mice.     

The hypothalamus as the primary brain region of metabolic abnormalities in APP/PS1 transgenic mouse model of Alzheimer's disease

Alzheimer's disease (AD) is an amyloid-related neurodegenerative disorder and is also considered to be a metabolic disease. Thus, investigation of metabolic mechanisms of amyloid pathology progression is of substantial importance for the diagnosis, prevention and treatment of AD. In the present study, cognitive function and brain metabolism were explored in the transgenic APP/PS1 mouse model of amyloid pathology at different ages. Using an NMR-based metabolomic approach, we examined metabolic changes in six different brain regions of wild-type and APP/PS1 mice at 1, 5 and 10 months of age. Learning and memory performance in mice was evaluated using the Morris water maze test. Furthermore, a generalized linear mixed model was employed to analyze the interaction effect between the mouse-type and brain region (or age) on metabolic alterations. Brain region-specific changes in energy metabolism occurred prior to a very early-stage of amyloid pathology (1 month of age) in APP/PS1 mice. A hypermetabolic state was identified in the brains of APP/PS1 mice at 5 months of age, and the hypothalamus was identified as the main brain region that underwent significant metabolic alterations. The cognitive function of APP/PS1 mice was impaired at 10 months of age; moreover, the hypermetabolic state identified in various brain regions at 5 months of age was also significantly decreased. In conclusion, our results suggest that a hypothalamic metabolism abnormality may comprise a potential indicator for the early-diagnosis and monitoring of amyloid pathology progression.     

APP/PS1双转基因小鼠的繁育、鉴定及评价

目的：评价APP/PS1双转基因小鼠基因表达及认知行为能力的变化,为AD的相关研究提供有效的动物模型。方法：采用雄、雌鼠1：1合笼配对的方式,令APP/PS1双转基因小鼠自然交配进行繁育。PCR鉴定APP/PS1双转基因鼠仔鼠的基因型后,选择APP/PS1阳性小鼠作为模型（AD）组,同批APP/PS1阴性为对照（CT）组,每组8只小鼠。以Morris水迷宫实验检测仔鼠的空间学习记忆能力,以HE染色、刚果红染色观察仔鼠脑片组织病理学改变。结果：①APP/PS1双转基因鼠仔鼠基因经PCR扩增,出现约360 bp的目的基因条带,表明成功繁育出转入APP/PS1基因的仔鼠;②Morris水迷宫实验结果显示,与7月龄阴性小鼠（CT组）比较,同月龄的双转基因AD组小鼠的空间学习记忆能力明显降低（P<0.05）;③HE染色结果显示,AD组小鼠海马结构及细胞形态出现明显异常;刚果红染色结果显示,AD组小鼠脑片组织出现β淀粉样蛋白斑块沉积。结论：APP/PS1双转基因小鼠较好地模拟了AD的病理变化及行为学特征,可作为研究AD发病机制及开发AD防治药物的实验工具。     

初步探讨鸟嘌呤核苷、姜黄素对AD双转基因小鼠学习记忆的影响

目的通过Morris水迷宫检测学习记忆和记忆保持能力,判断鸟嘌呤核苷、姜黄素对4月龄APPswe/PS1dE9双转基因小鼠认知功能的影响。方法将3月龄APPswe/PS1dE9双转基因小鼠随机分为模型组、盐酸多奈哌齐组0.92 mg/(kg·d)、鸟嘌呤核苷组20 mg/(kg·d)、姜黄素组200 mg/(kg·d)、姜黄素200 mg/(kg·d)和鸟嘌呤核苷组20 mg/(kg·d),每组12只;并以同月龄野生型C57/BL6J小鼠作对照。每天给药1次,连续给药1个月。应用Morris水迷宫进行行为学检测。结果鸟嘌呤核苷、姜黄素对空间探索、定位航行障碍有改善作用,尤其以姜黄素组明显。结论鸟嘌呤核苷、姜黄素能改善APPswe/PS1dE9双转基因小鼠的早期出现的认知障碍。     

Electroacupuncture Attenuates Reference Memory Impairment Associated with Astrocytic NDRG2 Suppression in APP/PS1 Transgenic Mice

Electroacupuncture (EA) has demonstrated therapeutic potential for the treatment of Alzheimer's disease (AD). A previous study reported that N-myc downstream-regulated gene 2 (NDRG2) was upregulated in the brain of patients with AD. In the present study, we investigated the effects of repeated EA administration on reference memory impairment and the role of NDRG2 in an amyloid precursor protein (APP)/presenilin-1 (PS1) double transgenic mouse model. Age-matched wild-type and transgenic mice were treated with EA (once per day for 30 min) for 4 weeks (four courses of 5 days EA administration and 2 days rest) beginning at 10 months of age. At seven and ten postnatal months of age and following a 4-week EA treatment regime, mice received training in the Morris water maze (MWM) and a probe test. Brain tissue was analyzed via Western blot and double-label immunofluorescence. Beginning at 7 months of age, APP/PS1 mice began to exhibit deficits in reference memory in the MWM test, an impairment associated with upregulation of glial fibrillary acidic protein (GFAP) and NDRG2. Four weeks of EA administration significantly ameliorated cognitive impairments and suppressed GFAP and NDRG2 upregulation. In conclusion, our findings demonstrated that EA administration can alleviate reference memory deficits and suppress NDRG2 upregulation in an AD transgenic mouse model. This study provides supportive evidence for EA as an effective therapeutic intervention for AD, as well as NDRG2 as a novel target for AD treatment.     

HDAC3 negatively regulates spatial memory in a mouse model of Alzheimer's disease

The accumulation and deposition of beta‐amyloid (Aβ) is a key neuropathological hallmark of Alzheimer's disease (AD). Histone deacetylases (HDACs) are promising therapeutic targets for the treatment of AD, while the specific HDAC isoforms associated with cognitive improvement are poorly understood. In this study, we investigate the role of HDAC3 in the pathogenesis of AD. Nuclear HDAC3 is significantly increased in the hippocampus of 6‐ and 9‐month‐old APPswe/PS1dE9 (APP/PS1) mice compared with that in age‐matched wild‐type C57BL/6 (B6) mice. Lentivirus ‐mediated inhibition or overexpression of HDAC3 was used in the hippocampus of APP/PS1 mice to investigate the role of HDAC3 in spatial memory, amyloid burden, dendritic spine density, glial activation and tau phosphorylation. Inhibition of HDAC3 in the hippocampus attenuates spatial memory deficits, as indicated in the Morris water maze test, and decreases amyloid plaque load and Aβ levels in the brains of APP/PS1 mice. Dendritic spine density is increased, while microglial activation is alleviated after HDAC3 inhibition in the hippocampus of 9‐month‐old APP/PS1 mice. Furthermore, HDAC3 overexpression in the hippocampus increases Aβ levels, activates microglia, and decreases dendritic spine density in 6‐month‐old APP/PS1 mice. In conclusion, our results indicate that HDAC3 negatively regulates spatial memory in APP/PS1 mice and HDAC3 inhibition might represent a potential therapy for the treatment of AD.     

(−)-Epigallocatechin-3-gallate alleviates spatial memory impairment in APP/PS1 mice by restoring IRS-1 signaling defects in the hippocampus

Alzheimer’s disease (AD) fundamentally represents a metabolic disease associated with brain insulin resistance. TNF-α/c-Jun N-terminal kinase (JNK) signaling plays a central role in serine phosphorylation of insulin receptor substrate-1 (IRS-1). (?)-Epigallocatechin-3-gallate (EGCG), a potent antioxidant, has been verified to attenuate peripheral insulin resistance by reducing IRS-1 signaling blockage. This study aimed to investigate the effects and possible mechanisms of EGCG on central IRS-1 signaling in vivo. APP/PS1 mice were treated with EGCG, and spatial memory was assessed by the Morris water maze test. Levels of soluble and insoluble Aβ42 in the hippocampus were determined by ELISA. The activation of NF-α/JNK and IRS signaling was detected by immunohistochemistry and Western blot analysis. Our results showed that EGCG ameliorated the impaired learning and memory in APP/PS1 mice. Notably, we found a significant reduction of IRS-1pS636 level accompanied with decreased Aβ42 levels in the hippocampus of 13-month-old female APP/PS1 mice after treatment with EGCG (2 or 6 mg/kg/day) for 4 weeks. Furthermore, EGCG treatment inhibited TNF-α/JNK signaling and increased the phosphorylation of Akt and glycogen synthase kinase-3β in the hippocampus of APP/PS1 mice. In conclusion, our study provides evidence that long-term consumption of EGCG may alleviate AD-related cognitive deficits by effectively attenuating central insulin resistance.     

Gardenia jasminoides J.Ellis extract GJ-4 alleviated cognitive deficits of APP/PS1 transgenic mice

BackgroundAccumulating evidence demonstrates that traditional Chinese medicines that act on multiple targets could effectively treat various multi-etiological diseases, including cerebrovascular diseases, Alzheimer's disease (AD), Parkinson's disease (PD) and so on. Previous studies have shown that crocin richments (GJ-4), Gardenia jasminoides J.Ellis extract, provide neuroprotective effects on cognitive impairments in AD mouse models. However, the mechanism how GJ-4 improves cognition remains still unclear.PurposeThe aim of this study was to uncover the protective effects and underlying mechanism of GJ-4 on PrP-hAβPPswe/PS1^ΔE9 (APP/PS1) transgenic mice.MethodsAPP/PS1 mice were given GJ-4 (10, 20, and 50 mg/kg), donepezil (5 mg/kg) and memantine (5 mg/kg) orally at eight months of age for 12 consecutive weeks. Morris water maze and novel object recognition were conducted to assess the cognitive ability of mice. The release of inflammatory cytokines was determined by RT-PCR assay, and the pathological features of neurons and microglia were assayed by immunohistochemistry and immunofluorescence assay. The expression of Aβ-related proteins and signaling pathways were determined by Western blot.ResultsThe behavioral results revealed that GJ-4 ameliorated the cognitive deficits of APP/PS1 mice measured by Morris water maze and novel object recognition tests. Mechanism studies indicated that GJ-4 significantly decreased β-amyloid (Aβ) level through reducing Aβ production and promoting Aβ degradation. It has been reported that Aβ plaques trigger the hyper-phosphorylation of tau protein in APP/PS1 mice. Consistent with previous studies, hyper-phosphorylation of tau was also occurred in APP/PS1 mice in the present study, and GJ-4 inhibited Tau phosphorylation at different sites. Overwhelming evidence indicates that neuroinflammation stimulated by Aβ and hyperphosphorylated tau is involved in the pathological progression of AD. We found that GJ-4 suppressed neuroinflammatory responses in the brain through regulating phosphatidylinositide 3-kinase/AKT (PI3K/AKT) signaling pathway activation, and subsequent expression of inflammatory proteins and release of inflammatory cytokines.ConclusionAltogether, GJ-4 ameliorated cognition of APP/PS1 transgenic mice through multiple targets, including Aβ, tau and neuroinflammation. This study provides a solid research basis for further development of GJ-4 as a potential candidate for the treatment of AD.     

APPswe／PS1dE9／TAU三转基因阿尔兹海默病大鼠模型的建立

目的大鼠的大脑比小鼠更大,是研究神经系统的重要模型。建立APPswe／PS1dE9／TAU三转基因大鼠,发展能更全面表现人类阿尔兹海默病表型的动物模型。方法构建人PrP—hAPP695K595N／M596L、PrP-hPS1dE9和PDGF-TAU转基因表达载体,显微注射法制备转基因大鼠。PCR法鉴定转基因首建鼠及其子代基因型。Western blot检测转基因大鼠脑组织中人APP、PS1和TAU蛋白的表达。Morris水迷宫检测6月龄三转基因大鼠学习记忆能力改变。APP、PHF—TAU免疫组织化学染色观察三转基因大鼠脑组织APP及TAU的表达。结果得到1个同时高表达人APP、PS1和TAU三个基因的转基因大鼠品系。转基因大鼠6月龄已经出现显著的行为学改变：学习记忆能力下降,病理学改变表现为过度磷酸化TAU增多和神经元胞浆内AB表达异常增加。结论成功建立了APPswe／PS1dE9／TAU三转AD大鼠,可做为新一代工具动物模型用于基础医学和AD转化医学研究。     

Overexpression of Human Apolipoprotein A-I Preserves Cognitive Function and Attenuates Neuroinflammation and Cerebral Amyloid Angiopathy in a Mouse Model of Alzheimer Disease

To date there is no effective therapy for Alzheimer disease (AD). High levels of circulating high density lipoprotein (HDL) and its main protein, apolipoprotein A-I (apoA-I), reduce the risk of cardiovascular disease. Clinical studies show that plasma HDL cholesterol and apoA-I levels are low in patients with AD. To investigate if increasing plasma apoA-I/HDL levels ameliorates AD-like memory deficits and amyloid-β (Aβ) deposition, we generated a line of triple transgenic (Tg) mice overexpressing mutant forms of amyloid-β precursor protein (APP) and presenilin 1 (PS1) as well as human apoA-I (AI). Here we show that APP/PS1/AI triple Tg mice have a 2-fold increase of plasma HDL cholesterol levels. When tested in the Morris water maze for spatial orientation abilities, whereas APP/PS1 mice develop age-related learning and memory deficits, APP/PS1/AI mice continue to perform normally during aging. Interestingly, no significant differences were found in the total level and deposition of Aβ in the brains of APP/PS1 and APP/PS1/AI mice, but cerebral amyloid angiopathy was reduced in APP/PS1/AI mice. Also, consistent with the anti-inflammatory properties of apoA-I/HDL, glial activation was reduced in the brain of APP/PS1/AI mice. In addition, Aβ-induced production of proinflammatory chemokines/cytokines was decreased in mouse organotypic hippocampal slice cultures expressing human apoA-I. Therefore, we conclude that overexpression of human apoA-I in the circulation prevents learning and memory deficits in APP/PS1 mice, partly by attenuating neuroinflammation and cerebral amyloid angiopathy. These findings suggest that elevating plasma apoA-I/HDL levels may be an effective approach to preserve cognitive function in patients with AD.     

Tau/APP/PS1三转基因小鼠模型的建立及生物学特征

目的:建立Tau/APP/PS1三转基因小鼠模型,从分子生物学、行为学及病理学角度研究其生物学特征。方法:将自行建立的Tau转基因小鼠与Jackson实验室引种的APP/PS1双转基因小鼠杂交、传代;PCR鉴定小鼠基因型;RT-PCR检测外源基因的转录;Western blot测定外源基因的蛋白表达;Bielschowsky氏染色法和ABC免疫组化法观察大脑神经纤维缠结和老年斑等病理改变;Morris水迷宫观测学习记忆的改变。结果:Tau/APP/PS1三转基因小鼠的大脑可转录和表达Tau、APP和PS1三种外源基因,6~8月龄时大脑皮层和海马可见神经元纤维缠结和老年斑,其学习记忆获得能力在6月龄开始受损。结论:建立的Tau/APP/PS1三转基因小鼠具有Tau和Aβ两种病理改变和学习记忆障碍,为深入探究Tau与Aβ的关系、阐明AD的发病机制以及研发靶点治疗药物提供实验工具。     

1H NMR metabolomics investigation of an Alzheimer’s disease (AD) mouse model pinpoints important biochemical disturbances in brain and plasma

In this study data generated by ¹H NMR were combined with chemometrics to analyse brain and plasma samples from APP/PS1 and wild type mice with the aim of developing a statistical model capable of predicting the features of Alzheimer’s disease (AD) displayed by this animal model. APP/PS1 is a well characterised double transgenic mouse model of AD and the results here demonstrate the potential of NMR technology as a platform for the detecting this disease. Using partial least squares discriminant analysis a model was built using both brain extracts (R² = 0.99; Q² = 0.66) and a high throughput method of plasma analysis (R² = 0.98; Q² = 0.75) capable of predicting AD in APP/PS1 mice. Analysis of brain extracts led to the elucidation of 20 metabolites and 16 of these were quantifiable. Relative brain levels of ascorbate, creatine, γ-aminobutyric acid and N-acetyl aspartic acid were significantly altered in APP/PS1 mice (p < 0.05). Analysis of plasma identified 14 metabolites and the levels of acetate, citrate, glutamate, glutamine, methionine, and an unknown signal were significantly altered in APP/PS1 mice (p < 0.05). Combining ¹H NMR spectral data with chemometrics has been previously used to study biochemical disturbances in various disease states. This study further indicates the translational potential of this technology for identifying AD in people attending the memory clinic.     

Delta-secretase triggers Alzheimer’s disease pathologies in wild-type hAPP/hMAPT double transgenic mice

Alzheimer’s disease (AD) is the most common neurodegenerative disease with multifactorial pathologies including Aβ containing senile plaques and neurofibrillary tangles (NFT) consisted of aggregated Tau. Most of the AD patients are sporadic and the familial mutation hereditary patients are composed only 1% of all cases. However, the current AD mouse models employ mutated APP, PS1, or even Tau mutant, in order to display a portion of AD pathologies. Delta-secretase (legumain, or asparaginyl endopeptidase, AEP) simultaneously cleaves both APP and Tau and augments Aβ production and Tau hyperphosphorylation and aggregation, contributing to AD pathogenesis. Here we show that δ-secretase is sufficient to promote prominent AD pathologies in wild-type hAPP/hMAPT double transgenic mice. We crossed hAPP l5 mice and hMAPT mice to generate double transgenic mouse model carrying both human wild-type APP and Tau. Compared to the single transgenic parents, these double transgenic mice demonstrated AD-related pathologies in one-year-old hAPP/hMAPT mice. Notably, overexpression of δ-secretase in hAPP/hMAPT double-transgenic mice evidently accelerated enormous senile plaques and NFT, associated with prominent synaptic defects and cognitive deficits. Hence, δ-secretase facilitates AD pathogenesis independent of any patient-derived mutation.Subject terms: Alzheimer''s disease, Neurological disorders     

Comparison between touchscreen operant chambers and water maze to detect early prefrontal dysfunction in mice

The relative lack of sensitive and clinically valid tests of rodent behavior might be one of the reasons for the limited success of the clinical translation of preclinical Alzheimer's disease (AD) research findings. There is a general interest in innovative behavioral methodology, and protocols have been proposed for touchscreen operant chambers that might be superior to existing cognitive assessment methods. We assessed and analyzed touchscreen performance in several novel ways to examine the possible occurrence of early signs of prefrontal (PFC) functional decline in the APP/PS1 mouse model of AD. Touchscreen learning performance was compared between APP/PS1-21 mice and wildtype littermates on a C57BL/6J background at 3, 6 and 12 months of age in parallel to the assessment of spatial learning, memory and cognitive flexibility in the Morris water maze (MWM). We found that older mice generally needed more training sessions to complete the touchscreen protocol than younger ones. Older mice also displayed defects in MWM working memory performance, but touchscreen protocols detected functional changes beginning at 3 months of age. Histological changes in PFC of APP/PS1 mice indeed occurred as early as 3 months. Our results suggest that touchscreen operant protocols are more sensitive to PFC dysfunction, which is of relevance to the use of these tasks and devices in preclinical AD research and experimental pharmacology.     

Imbalance of Microglial TLR4/TREM2 in LPS-Treated APP/PS1 Transgenic Mice: A Potential Link Between Alzheimer’s Disease and Systemic Inflammation

Clinically, superimposed systemic inflammation generally has significant deleterious effects on the Alzheimer’s disease (AD) progression. However, the related molecular mechanisms remain poorly understood. Microglial toll-like receptor 4 (TLR4) and triggering receptor expressed on myeloid cells 2 (TREM2) are two key regulators of inflammation that may play an essential role in this complex pathophysiological process. In this study, intraperitoneal injection of lipopolysaccharide (LPS) into APP/PS1 transgenic AD model was used to mimic systemic inflammation in the development of AD. Initial results from the cortex showed that compared with wild-type mice, APP/PS1 mice exhibited elevated gene and protein expression levels of both TLR4 and TREM2 with different degree. Interestingly, after LPS treatment, TLR4 expression was persistently up-regulated, while TREM2 expression was significantly down-regulated in APP/PS1 mice, suggesting that the negative regulatory effect of TREM2 on inflammation might be suppressed by LPS-induced hyperactive TLR4. This imbalance of TLR4/TREM2 contributed to microglial over-activation, followed by increased neuronal apoptosis in the cortex of APP/PS1 mice; these changes did not alter the expression level of Aβ_1?42. Similar alterations were observed in our in vitro experiment with β-amyloid_1–42 (Aβ_1–42)-treated N9 microglia. Further, Morris water maze (MWM) testing data indicated that LPS administration acutely aggravated cognitive impairment in APP/PS1 mice, suggesting that the addition of systemic inflammation can potentially accelerate the progression of AD. Collectively, we conclude that an imbalance of TLR4/TREM2 may be a potential link between AD and systemic inflammation. TREM2 can serve as a potential therapeutic target for treating systemic inflammation in AD progression.

     

Curcumin improves memory deficits by inhibiting HMGB1-RAGE/TLR4-NF-κB signalling pathway in APPswe/PS1dE9 transgenic mice hippocampus

Amyloid-β (Aβ) deposition in the brain has been implicated in the development of Alzheimer's disease (AD), and neuroinflammation generates AD progression. Therapeutic effects of anti-inflammatory approaches in AD are still under investigation. Curcumin, a potent anti-inflammatory and antioxidant, has demonstrated therapeutic potential in AD models. However, curcumin's anti-inflammatory molecular mechanisms and its associated cognitive impairment mechanisms in AD remain unclear. The high-mobility group box-1 protein (HMGB1) participates in the regulation of neuroinflammation. Herein, we attempted to evaluate the anti-inflammatory effects of chronic oral administration of curcumin and HMGB1 expression in APP/PS1 transgenic mice AD model. We found that transgenic mice treated with a curcumin diet had shorter escape latencies and showed a significant increase in percent alternation, when compared with transgenic mice, in the Morris water maze and Y-maze tests. Additionally, curcumin treatment could effectively decrease HMGB1 protein expression, advanced glycosylation end product-specific receptor (RAGE), Toll-like receptors-4 (TLR4) and nuclear factor kappa B (NF-κB) in transgenic mice hippocampus. However, amyloid plaques detected with thioflavin-S staining in transgenic mice hippocampus were not affected by curcumin treatment. In contrast, curcumin significantly decreased GFAP-positive cells, as assessed by immunofluorescence staining. Taken together, these data indicate that oral administration of curcumin may be a promising agent to attenuate memory deterioration in AD mice, probably inhibiting the HMGB1-RAGE/TLR4-NF-κB inflammatory signalling pathway.     

Age-related changes of brain iron load changes in the frontal cortex in APPswe/PS1ΔE9 transgenic mouse model of Alzheimer's disease

Alzheimer's disease (AD) as a neurodegenerative brain disorder is a devastating pathology leading to disastrous cognitive impairments and dementia, associated with major social and economic costs to society. Iron can catalyze damaging free radical reactions. With age, iron accumulates in brain frontal cortex regions and may contribute to the risk of AD. In this communication, we investigated the age-related brain iron load changes in the frontal cortex of 6- and 12-month-old C57BL/6J (C57) and APP_swe/PS1_ΔE9 (APP/PS1) double transgenic mouse by using graphite furnace atomic absorption spectrometry (GFAAS) and Perls’ reaction. In the present study, we also evaluated the age-related changes of DMT1 and FPN1 by using Western blot and qPCR. We found that compared with 6-month-old APP/PS1 mice and the 12-month-old C57 mice, the 12-month-old APP/PS1 mice had increased iron load in the frontal cortex. The levels of DMT1 were significantly increased and the FPN1 were significantly reduced in the frontal cortex of the 12-month-old APP/PS1 mice than that in the 6-month-old APP/PS1 mice and 12-month-old C57 mice. We conclude that in AD damage occurs in conjunction with iron accumulation, and the brain iron load associated with loss control of the brain iron metabolism related protein DMT1 and FPN1 expressions.     

B-GOS对阿尔茨海默病转基因小鼠认知行为和抑郁情绪的影响*

目的: 观察新型低聚半乳糖(B-GOS)对APP/PS1/tau阿尔茨海默病转基因小鼠认知行为和抑郁情绪的影响。方法: 选用5月龄雄性APP/PS1/tau AD转基因小鼠和C57BL/6J对照小鼠,分为C57+Vehicle组、C57+B-GOS组、APP/PS1/tau+Vehicle组和APP/PS1/tau+B-GOS组,每组10只。B-GOS连续给予5个月后,依次采用旷场实验、新物体识别实验、Y迷宫实验、Morris水迷宫实验、悬尾实验、强迫游泳实验和条件恐惧实验,检测各组小鼠的认知行为表现和抑郁情绪变化。结果: ① 旷场实验:APP/PS1/tau+Vehicle组小鼠在旷场中央区域的活动时间百分比显著低于C57+Vehicle组小鼠(P＜0.01),经过B-GOS干预后显著升高(P＜0.05)。② 新物体识别实验:APP/PS1/tau+Vehicle组小鼠的新物体识别指数(NOI)显著低于C57+Vehicle组小鼠(P＜0.01), 经过B-GOS干预后显著升高(P＜0.05)。③ Y迷宫实验:APP/PS1/tau+Vehicle组小鼠的自发交替正确率显著低于C57+Vehicle组小鼠(P＜0.01),经过B-GOS干预后显著升高(P＜0.01)。④ 经典水迷宫实验:APP/PS1/tau+Vehicle组小鼠在第4日和第5日的逃避潜伏期显著长于C57+Vehicle组小鼠(P＜0.01),经过B-GOS干预后均显著缩短(P＜0.05);在空间探索阶段,APP/PS1/tau+Vehicle组小鼠的目标象限游泳时间百分比和穿越平台次数均显著低于C57+Vehicle组小鼠(P＜0.01),经过B-GOS干预后均显著增加(P＜0.01)。⑤ 悬尾试验和强迫游泳实验:APP/PS1/tau+Vehicle组小鼠的不动时间百分比均显著高于C57+Vehicle组小鼠(P＜0.01),经过B-GOS干预后均显著降低(P＜0.01)。⑥ 条件恐惧实验:在条件刺激(CS)作用前,各组小鼠的僵直比率无统计学差异(P＞0.05)。CS作用后,APP/PS1/tau+Vehicle组小鼠的僵直比率显著低于C57+Vehicle 组小鼠(P＜0.01),经过B-GOS干预后均显著上升(P＜0.01)。结论: B-GOS能够较大程度地逆转APP/PS1/tau小鼠的认知行为损伤,并减轻其抑郁情绪。     

NGI重组DNA疫苗对转基因AD小鼠的治疗作用

目的研究NGI对转基因阿尔茨海默病小鼠的治疗作用。方法构建包含小鼠OMgp细胞外8LRP重复序列,人Tenascin-R的EGF-L结构域,以及人Nogo-A的氨基端和66个氨基酸细胞外域的重组质粒,肌肉注射AD小鼠,空载体组和空白对照组为对照组。水迷宫检测小鼠行为学差别,免疫组化检测其病理差别。结果4.5月龄AD小鼠经过水迷宫隐蔽平台实验,2d后疫苗组小鼠潜伏期比对照组缩短30%（P〈0.05）。探索实验显示3月龄疫苗组比空载体组和空白对照组小鼠穿越目标象限的次数分别增加48%和44%（P〈0.05）。结论NGI重组DNA疫苗能够提高转基因AD小鼠的学习与记忆能力。