Neuroprotective effects of echinacoside in the mouse MPTP model of Parkinson's disease

In the present study, we investigated the neuroprotective effects of echinacoside, a phenylethanoid glycoside extracted from the medicinal Chinese herb Cistanches salsa, against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced dopaminergic toxicity. We confirmed that exposure to MPTP in mice leads to permanent behavioral deficits and depletion of dopamine and its metabolites. When administered prior to MPTP, echinacoside reduced behavioral deficits, increased striatal dopamine and dopamine metabolite levels, reduced cell death, and led to a marked increase in tyrosine hydroxylase expression relative to mice treated with MPTP alone. In addition, pre-treatment with echinacoside significantly reduced caspase-3 and caspase-8 activation in 1-methyl-4-phenylpyridinium (MPP(+))-induced apoptosis in cerebellar granule neurons. Taken together, these findings suggest that echinacoside improves the behavioral and neurochemical outcomes in MPTP mice model of Parkinson's disease and inhibits caspase-3 and caspase-8 activation in cerebellar granule neurons, making the compound an attractive candidate treatment for various neurodegenerative disorders, including Parkinson's disease.     

类叶升麻苷对MPTP所致帕金森病小鼠模型的神经保护作用

目的研究类叶升麻苷在MPTP诱导的C57小鼠的帕金森病(PD)模型中的神经保护作用及机制。方法通过自主活动实验和滚筒实验研究动物的行为表现,通过高效液相电化学检测方法观察脑纹状体多巴胺的变化,通过脑黑质酪氨酸羟化酶(tyroxinehydroxylase,TH)免疫组化染色观察多巴胺能神经元的损伤程度。并对黑质纹状体进行α-突触核蛋白(α-synuclein)的免疫印迹分析以探讨药物作用机制。结果①经MPTP诱导的C57小鼠,其自主活动次数、滚筒运动潜伏期均低于对照组(P<0·01);纹状体多巴胺含量明显降低(P<0·01);多巴胺能神经元数量明显减少;黑质纹状体α-synuclein蛋白水平下降。②经类叶升麻苷(10、30mg·kg-1)预处理后能明显改善MPTP诱导的C57小鼠的行为学表现,增加脑内多巴胺递质的含量,增加多巴胺能神经元的数量,增加黑质纹状体α-synuclein蛋白水平。结论类叶升麻苷具有神经保护作用,能对抗MPTP诱导的C57小鼠PD模型中的神经损伤。其机制可能与上调α-synuclein蛋白水平有关。     

Gene expression profile of amyloid beta protein-injected mouse model for Alzheimer disease

Aim: To investigate the gene expression profile changes in the cerebral cortex of mice injected icv with amyloid beta-protein (Aβ) fragment 25-35 using cDNA microarray. Methods: Balb/c mice were randomly divided into a control group and Aβ-treated group. The Morris water maze test was performed to detect the effect of Aβ-injection on the learning and memory of mice. Atlas Mouse 1.2 Expression Arrays containing 1176 genes were used to investigate the gene expression pattern of each group. Results: The gene expression profiles showed that 19 genes including TBX1, NF-κB, AP-1/c-Jun, cadherin, integrin, erb-B2, and FGFR1 were up-regulated after 2 weeks of icv administration of Aβ; while 12 genes were down-regulated, including NGF, glucose phosphate isomerase 1, AT motifbindingfactor 1, Na^ /K^ -ATPase, and Akt. Conclusions: The results provide important leads for pursuing a more complete understanding of the molecular events of Aβ-injection into mice with Alzheimer disease.     

氟西汀对阿尔茨海默病模型小鼠的神经元保护作用

目的:研究氟西汀对老年APP/PS1双重转基因阿尔茨海默病模型小鼠学习记忆能力的影响及对神经元的保护作用.方法:实验分为动物实验和细胞实验.动物实验中取APP/PS1双重转基因小鼠随机分为氟西汀组(n=8)和生理盐水组(n=8),另取C57同窝生同月龄正常小鼠10只为对照组.氟西汀组小鼠给予氟西汀(10 mg/kg)腹腔注射,生理盐水组及对照组注射等量生理盐水1次/d,持续8周.Morris水迷宫实验进行行为学检测.Tunel染色检测海马区神经元凋亡.细胞实验中将人神经母细胞瘤细胞(SH-SY5Y)培养48 h后分为正常组、Aβ组、氟西汀组和氟西汀+Aβ组,后3组分别在含10μmol/L β-淀粉样蛋白、100 nmol/L氟西汀和100 nmol/L氟西汀+10μmol/L β-淀粉样蛋白的DMEM中继续培养48 h.行原位细胞凋亡染色检测各组细胞凋亡.结果:水迷宫定位航行实验中,氟西汀组小鼠较生理盐水组相比平均潜伏期明显缩短(P＜0.01);空间探索实验中跨越平台次数增加(P＜0.01);海马区凋亡神经元数量减少(P＜0.01).细胞实验中,氟西汀组和氟西汀+Aβ组与Aβ组相比,凋亡细胞数量明显减少(P＜0.01).结论:氟西汀对神经元细胞有保护作用,能减少神经元的凋亡,长期服用氟西汀能显著改善APP/PS1阿尔茨海默病模型小鼠学习记忆力能力.     

Neuroprotective effect of kaempferol against a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced mouse model of Parkinson's disease

In the present study, we investigated the neuroprotective effects of kaempferol in the mouse model of Parkinson's disease, which was induced by neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). We confirmed that MPTP led to behavioral deficits, depletion of dopamine and its metabolites, reduction in superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) activity, and the elevation of malondialdehyde (MDA) levels in the substantia nigra. When administered prior to MPTP, kaempferol improved motor coordination, raised striatal dopamine and its metabolite levels, increased SOD and GSH-PX activity, and reduced the content of MDA compared with mice treated with MPTP alone. Immunohistochemical studies using anti-tyrosine hydroxylase (TH) antibody showed that medication of kaempferol could prevent the loss of TH-positive neurons induced by MPTP. Taken together, we propose that kaempferol has shown anti-parkinsonian properties in our studies. More work is needed to explore detailed mechanisms of action.     

Transgenic mouse models of Alzheimer disease: developing a better model as a tool for therapeutic interventions

Alzheimer disease (AD) is the leading cause of dementia among elderly. Currently, no effective treatment is available for AD. Analysis of transgenic mouse models of AD has facilitated our understanding of disease mechanisms and provided valuable tools for evaluating potential therapeutic strategies. In this review, we will discuss the strengths and weaknesses of current mouse models of AD and the contribution towards understanding the pathological mechanisms and developing effective therapies.     

中药提取物CTE对MPTP所致帕金森病小鼠模型的神经保护作用

目的:研究中药提取物CTE对1-甲基-4-苯基-1,2,3,6-四氢吡啶(MPTP)所致帕金森病小鼠模型是否具有神经保护作用。方法:首先建立MPTP所致帕金森病小鼠模型,连续4 d给予MPTP(30 mg.kg-1,qd,ip)。用高低剂量(50和100 mg.kg-1,qd,ig)中药提取物CTE预处理MPTP所致帕金森模型小鼠。之后进行行为学检测,包括一般行为学检测和滚筒实验。最后,用HPLC-EC法测定纹状体中多巴胺(DA)及其代谢产物二羟苯乙酸(DOPAC)和高香草酸(HVA)含量。结果:在MPTP所致的帕金森病小鼠模型,中药提取物CTE能显著改善小鼠的行为能力;且能显著提高小鼠纹状体内多巴胺含量。结论:中药提取物CTE对MPTP所致帕金森病小鼠模型有神经保护作用。     

MAPK/ERK信号通路参与褪黑素对阿尔茨海默病大鼠小脑的神经保护作用

目的观察褪黑素能否通过MAPK/ERK信号通路,发挥对阿尔茨海默病大鼠小脑的神经保护作用。方法将32只♂SD大鼠随机分为4组:对照组、Aβ_(1-42)侧脑室注射组(AD)、褪黑素腹腔注射组(MT)、Aβ_(1-42)侧脑室注射结合褪黑素腹腔注射组(AD+MT)。HE染色观察各组大鼠小脑皮层的病理学变化;免疫荧光染色观察各组颗粒细胞标记物NeuN、浦肯野细胞标记物Calbindle和p-ERK蛋白的表达情况;Western blot检测各组小脑组织中p-ERK蛋白的表达。结果 HE染色结果显示,AD组大鼠小脑皮层的神经元数量减少,细胞排列紊乱,细胞形态改变,褪黑素可明显减轻侧脑室注射Aβ_(1-42)对小脑的病理学损害;免疫荧光结果显示,与AD组相比,AD+MT组颗粒细胞标记物NeuN的蛋白表达增加,以Calbindin标记的浦肯野细胞个数明显增多(P<0.01), p-ERK蛋白表达减少(P<0.01);Western blot结果显示,与AD组相比,AD+MT组小脑组织中p-ERK蛋白表达水平降低。结论褪黑素可能通过抑制MAPK/ERK信号通路的激活,发挥对小脑皮层神经原的保护作用。     

Neuroprotective effect of gold nanoparticles composites in Parkinson's disease model

Parkinson’s disease (PD) is second most common neurodegenerative disorder worldwide. Although drugs and surgery can relieve the symptoms of PD, these therapies are incapable of fundamentally treating the disease. For PD patients, over-expression of α-synuclein (SNCA) leads to the death of dopaminergic neurons. This process can be prevented by suppressing SNCA over-expression through RNA interference. Here, we successfully synthesized gold nanoparticles (GNP) composites (CTS@GNP-pDNA-NGF) via the combination of electrostatic adsorption and photochemical immobilization, which could load plasmid DNA (pDNA) and target specific cell types. GNP was transfected into cells via endocytosis to inhibiting the apoptosis of PC12 cells and dopaminergic neurons. Simultaneously, GNP composites are also used in PD models in vivo, and it can successfully cross the blood-brain barrier by contents of GNP in the mice brain. In general, all the works demonstrated that GNP composites have good therapeutic effects for PD models in vitro and in vivo.     

二苯乙烯苷对帕金森病模型大鼠行为学及多巴胺能神经元的影响

［摘要］　目的：观察何首乌主要有效成分二苯乙烯苷（TSG）对帕金森病（PD）模型大鼠行为学及脑内黑质多巴胺能神经元的影响。方法：采用6-羟基多巴胺（6-OHDA）单侧脑内黑质致密部（SNC）和中脑腹侧被盖区（VTA）两点注射法制备PD大鼠模型后，灌胃给予TSG低、中、高剂量 (50，100，200 mg&#8226;kg-1)，qd，连续5周。实验同时设正常对照组和美多芭阳性对照组（125 mg&#8226;kg-1），每组10只。用旋转行为检测及Rotarod试验观察各组大鼠的行为学变化，用免疫组化法观察大鼠脑黑质酪氨酸羟化酶(TH)阳性神经元的表达，用高效液相色谱-电化学法（HPLC-ECD）测定大鼠脑黑质多巴胺（DA）及3,4-二羟基苯乙酸（DOPAC）含量。结果：行为学检测结果表明，模型组大鼠旋转次数及运动协调性均低于正常对照组(P<0.01)，而TSG与美多芭给药可改善大鼠旋转行为及运动协调性。TH免疫组化检测结果显示，TSG处理组脑黑质部位损毁较轻，有较多残存的TH阳性细胞；而模型组黑质大部损毁，几乎无残存的TH阳性细胞；从HPLC-ECD测定结果可以看出，与正常对照组比较，模型组DA及DOPAC含量下降显著(P<0.05)，与模型组相比，TSG处理组脑内DA及DOPAC含量明显增加(P<0.05)。结论：TSG可改善PD大鼠的行为学改变，增加黑质-纹状体多巴胺及其代谢物含量并提高黑质多巴胺能神经元的残存率，提示TSG对PD可能具有一定的神经保护作用。     

Neuroprotective role of naringenin against methylmercury induced cognitive impairment and mitochondrial damage in a mouse model

Human exposure to organomercurials like methylmercury (MeHg) may occur by consumption of contaminated seafood, affecting various vital organs especially, brain contributing to neuro disorders. The citrus flavanone, naringenin (NAR) has shown strong antioxidant and anti-inflammatory effects and therefore may exert cytoprotective effect against xenobiotic agents. Herein, we investigated the neuroprotective role of NAR against MeHg induced functional changes in mitochondria, neuronal cell death and cognitive impairment in a mouse model.A neurotoxic dose of MeHg (4 mg/kg.b.wt.) was administered orally to mice for 15 days. This resulted in the reduction of GSH and GST, an increase in mitochondrial DNA damage and memory impairment. On the contrary, NAR pre-treatment (100 mg/kg.b.wt.), helped in lowering the oxidative burden which in turn maintained mitochondrial function and prevented induced neuronal cell death, ultimately improving the cognitive impairment. As MeHg intoxication occurs chronically, consumption of the dietary components rich in NAR may have its positive human health impact, ultimately improving the quality of life.     

Neuroprotective potential of CB1 receptor agonists in an in vitro model of Huntington's disease

Background and purpose:

The therapeutic potential of cannabinoids in Huntington''s disease (HD) has been investigated by several groups with complex and sometimes contrasting results. We sought to examine key points of intersection between cannabinoid receptor 1 (CB₁) signalling, survival and the formation of mutant huntingtin aggregates in HD.

Experimental approach:

Using a simplified pheochromocytoma (PC12) cell model of HD expressing exon 1 of wild-type or mutant huntingtin, we assayed cell death and aggregate formation using high-throughput cytotoxicity and image-based assays respectively.

Key results:

CB₁ activation by HU210 conferred a small but significant level of protection against mutant huntingtin-induced cell death. Pertussis toxin uncoupled HU210 from the inhibition of cAMP, preventing rescue of cell death. Phosphorylation of extracellular signal-regulated kinase (ERK) was also critical to CB₁-mediated rescue. Conversely, treatments that elevated cAMP exacerbated mutant huntingtin-induced cell death. Despite opposing effects on HD cell survival, both HU210 and compounds that elevated cAMP increased the formation of mutant huntingtin aggregates. The increase in aggregation by HU210 was insensitive to Pertussis toxin and UO126, suggesting a G-protein alpha subtype s (G_s)-linked mechanism.

Conclusions and implications:

We suggest that the CB₁ receptor, through G-protein alpha subtype i/o (G_i/o)-linked, ERK-dependent signal transduction, is a therapeutic target in HD. However the protective potential of CB₁ may be limited by promiscuous coupling to G_s, the stimulation of cAMP formation and increased aggregate formation. This may underpin the poor therapeutic efficacy of cannabinoids in more complex model systems and suggest that therapies that are selective for the G_i/o, ERK pathway may be of most benefit in HD.This article is part of a themed issue on Cannabinoids. To view the editorial for this themed issue visit http://dx.doi.org/10.1111/j.1476-5381.2010.00831.x     

Neuroprotective effect of flupirtine in prion disease

Apoptotic neuronal cell death is a hallmark of prion diseases. The apoptotic process in neuronal cells is thought to be caused by the scrapie prion protein, PrPSc, and can be experimentally induced by its peptide fragment, PrP106-126. This process is a target for potential drugs to combat prion disease or to ameliorate its symptoms. Flupirtine (Katadolon), a pyridine derivative that is in clinical use as a nonopioid analgesic, has a potent cytoprotective effect, at concentrations above 1 microg/mL, on neuronal cells treated with PrP(Sc) or PrP106-126. This drug acts as an N-methyl-D-aspartate (NMDA) antagonist, but does not bind to NMDA receptors. Flupirtine normalizes the level of intracellular glutathione and increases the expression of the antiapoptotic Bcl-2 protein in neuronal cells exposed to prion protein. In view of its favorable pharmacokinetic profile, flupirtine is the first drug to be considered as a potential treatment for Creutzfeldt-Jakob disease, the human form of prion diseases. Clinical trials are underway.     

Therapeutic potential in Alzheimer disease

Oxidative damage is shown to affect every class of biological macromolecule in Alzheimer disease. Disruptions in iron and copper homeostasis are understood as being key players in neurodegenerative disease pathogenesis. Metal homeostasis as it pertains to alterations in brain function in neurodegenerative diseases is reviewed here with its relations to oxidative stress. While there is substantial documented evidence for alterations in transition metal metabolism, redox-activity and localization, it is also important to note that alterations in specific copper- and iron-containing metalloenzymes also contribute to the neurodegenerative process. Understanding these changes offers the opportunity to identify pathways where modification of the disease process can offer effective clinical intervention, from gene therapy to pharmaceuticals with antioxidant and chelating properties.     

Trifluralin toxicity in a Chagas disease mouse model

Even though trifluralin (alpha,alpha,alpha-2,6-dinitro-N-N-dipropyl-p-toluidine) is effective for the treatment of experimental Chagas disease, more preclinical toxicity studies need to be performed. Cell toxicity of trifluralin was studied in Hep-G2 and Vero C76 cells treated with 50 and 150 microM trifluralin. The results show that duplication time, amount of cellular protein and cell protein/DNA values were normal. Histological, haematological and chemical parameters were measured in CF1 mice after oral trifluralin administration. Acute toxic effects were assayed by administration of 50 or 200 mg/kg body weight daily for 30 days, and chronic effects by administration of 200 mg/kg body weight once a week for 90 days (n = 20). In the acute scheme treatment, hepatic (glutamic-pyruvic, glutamic-oxalacetic and alkaline phosphatase activities; proteins and albumin plasma concentrations) and pancreatic (amylase, glycaemia) functions were normal. Mean corpuscular volume, haemoglobin and haematocrit decreased. Creatine phosphokinase, lactate dehydrogenase and glutamic-oxalacetic activity increased, suggesting lesion in myocardial tissue. Histology was normal, excepting for the heart (mild myocarditis). Similar results were observed in acutely treated animals. There were no differences in body weight gain for treated mice compared to controls. In view of the published therapeutic effects of trifluralin on CF1 Chagas disease model and considering the present results, trifluralin seems to be a moderately toxic drug with a potential selective effect on the myocardium.     

Spatial deficits in a mouse model of Parkinson disease

Rationale Accumulating evidence in humans demonstrated that visuo-spatial deficits are the most consistently reported cognitive abnormalities in Parkinson disease (PD). These deficits have been generally attributed to cortical dopamine degeneration. However, more recent evidence suggests that dopamine loss in the striatum is responsible for the visuo-spatial abnormalities in PD. Studies based on animal models of PD did not specifically address this question. Objectives Thus, the first goal of this study was to analyze the role of dopamine within the dorsal striatum in spatial memory. We tested bilateral 6-OHDA striatal lesioned CD1 mice in an object–place association spatial task. Furthermore, to see whether the effects were selective for spatial information, we measured how the 6-OHDA-lesioned animals responded to a non-spatial change and learned in the one-trial inhibitory avoidance task. Results The results demonstrated that bilateral (approximately 75%) dopamine depletion of the striatum impaired spatial change discrimination. On the contrary, no effect of the lesion was observed on non-spatial novelty detection or on passive avoidance learning. Conclusions These results confirm that dopamine depletion is accompanied by cognitive deficits and demonstrate that striatal dopamine dysfunction is sufficient to induce spatial information processing deficits.     

Neuroprotective effect of taurine in 3-nitropropionic acid-induced experimental animal model of Huntington's disease phenotype

An experimental animal model of Huntington's disease (HD) phenotype was induced using the mycotoxin 3-nitropropionic acid (3-NP) and was well characterized behaviorally, neurochemically, morphometrically and histologically. Administration of 3-NP caused a reduction in prepulse inhibition (PPI) of acoustic startle response, locomotor hyper- and/or hypoactivity, bilateral striatal lesions, brain oxidative stress, and decreased striatal gamma-aminobutyric acid (GABA) levels. Taurine is a semi-essential beta-amino acid that was demonstrated to have both antioxidant and GABA-A agonistic activity. In this study, treatment with taurine (200 mg/kg daily for 3 days) prior to 3-NP administration reversed both reduced PPI response and locomotor hypoactivity caused by 3-NP injection. Taurine pretreatment also caused about 2-fold increase in GABA concentration compared to 3-NP-treated animals. In addition, taurine demonstrated antioxidant activity against oxidative stress induced by 3-NP administration as evidenced by the reduced striatal malondialdehyde (MDA) and elevated striatal glutathione (GSH) levels. Histochemical examination of striatal tissue showed that prior administration of taurine ahead of 3-NP challenge significantly increased succinate dehydrogenase (SDH) activity compared to 3-NP-treated animals. Histopathological examination further affirmed the neuroprotective effect of taurine in 3-NP-induced HD in rats. Taken together, one may conclude that taurine has neuroprotective role in the current HD paradigm due, at least partly, to its indirect antioxidant effect and GABA agonistic action.     

Effects of LW-AFC,a new formula derived from Liuwei Dihuang decoction,on intestinal microbiome in senescence-accelerated mouse prone 8 strain,a mouse model of Alzheimer disease

OBJECTIVE To investigate the effects of LW-AFC,a new formula derived fromLiuwei Dihuang decoction,on gut microbiota and the behavior of learning and memory of SAMP8 mice,a mouse model of Alzheimer Disease(AD),and identify the specific intestinal microbiota correlating with cognitive ability.METHODS Morris-water maze test,novel object recognition test and shuttle-box test were conducted to observe the ability of learning and memory.16S rRNA amplicon sequencing(Illumina,San Diego,CA,USA)was employed to investigate gut microbiota.RESULTS The treatment of LW-AFC improved cognitive impairments of SAMP8 mice,including spatial learning and memory ability,active avoidance response,and object recognition memory capability.Our data indicated that there were significantly 8 increased and 12 decreased operational taxonomic units(OTUs)in the gut microbiota of SAMP8 mice compared with senescence accelerated mouse resistant 1(SAMR1) strains,the control of SAMP8 mice.The treatment of LW-AFC altered 22(16 increased and 6 decreased)OTUs in SAMP8 mice and among them,15 OTUs could be reversed by LW-AFC treatment resulting in a microbial composition similar to that of SAMR1 mice.We further showed that there were7(3 negative and 4 positive correlation)OTUs significantly correlated with all the three types of cognitive abilities,at the order level,including Bacteroidales,Clostridiales,Desulfovibrionales,CW040,and two unclassified orders.LW-AFC had influences on bacterial taxa correlated with the abilities of learning and memory in SAMP8 mice and restored them to SAMR1 mice.CONCLUSION The effects of LW-AFC on improving cognitive impairments of SAMP8 mice might be via modulating intestinal microbiome and LW-AFC could be used as a potential anti-AD agent.     

Nanoparticles-based anti-aging treatment of Alzheimer’s disease

Age is the strongest risk factor for Alzheimer’s disease (AD). In recent years, the relationship between aging and AD has been widely studied, with anti-aging therapeutics as the treatment for AD being one of the mainstream research directions. Therapeutics targeting senescent cells have shown improvement in AD symptoms and cerebral pathological changes, suggesting that anti-aging strategies may be a promising alternative for AD treatment. Nanoparticles represent an excellent approach for efficiently crossing the blood-brain barrier (BBB) to achieve better curative function and fewer side effects. Thereby, nanoparticles-based anti-aging treatment may exert potent anti-AD therapeutic efficacy. This review discusses the relationship between aging and AD and the application and prospect of anti-aging strategies and nanoparticle-based therapeutics in treating AD.