尿酸减轻6-羟基多巴胺对PC12细胞的毒性作用

目的：评价尿酸减轻6．羟基多巴胺（6-OHDA）对PC12细胞的毒性作用。方法：应用PCI2细胞制作帕金森细胞模型,分为对照组、尿酸组、6-OHDA组、尿酸＋6-OHDA组。采用MTT测定各组PC12细胞活性,免疫荧光法观察各组PCI2细胞caspase-3激活情况,流式细胞术检测各组PC12细胞凋亡率。尿酸100～400μmol·L^-1不影响PCI2细胞生存率,尿酸100～400μmol·L-1可显著提高6-OHDA50gmol-L。作用6、12和24h造成的PCI2细胞生存率的下降（P〈0．01）;尿酸能减少6-OHDA导致的PCI2细胞caspase-3激活,降低6-OHDA导致的凋亡率（P〈0．05）。结论：尿酸具有减轻6-OHDA对PC12细胞的毒性作用。     

Protective effect of alpha-synuclein knockdown on methamphetamine-induced neurotoxicity in dopaminergic neurons

The over-expression of α-synuclein is a major factor in the death of dopaminergic neurons in a methamphetamine-induced model of Parkinson's disease. In the present study, α-synuclein knockdown rats were created by injecting α-synuclein-shRNA lentivirus stereotaxically into the right striatum of experimental rats. At 2 weeks post-injection, the rats were injected intraper-itoneally with methamphetamine to establish the model of Parkinson's disease. Expression of α-synuclein mRNA and protein in the right striatum of the injected rats was significantly down-regulated. Food intake and body weight were greater in α-synuclein knockdown rats, and water intake and stereotyped behavior score were lower than in model rats. Striatal dopamine and tyrosine hydroxylase levels were significantly elevated in α-synuclein knockdown rats. Moreover, superoxide dismutase activity was greater in α-synuclein knockdown rat striatum, but the levels of reactive oxygen species, malondialdehyde, nitric oxide synthase and nitrogen monoxide were lower compared with model rats. We also found that α-synuclein knockdown inhibited metham-phetamine-induced neuronal apoptosis. These results suggest that α-synuclein has the capacity to reverse methamphetamine-induced apoptosis of dopaminergic neurons in the rat striatum by inhibiting oxidative stress and improving dopaminergic system function.     

The role of quercetin on the survival of neuron-like PC12 cells and the expression of α-synuclein

Both genetic and environmental factors are important in the pathogenesis of Parkinson's disease. As α-synuclein is a major constituent of Lewy bodies, a pathologic hallmark of Parkinson's disease, genetic aspects of α-synuclein is widely studied. However, the influence of dietary factors such as quercetin on α-synuclein was rarely studied. Herein we aimed to study the neuroprotective role of quercetin against various toxins affecting apoptosis, autophagy and aggresome, and the role of quercetin on α-synuclein expression. PC12 cells were pre-treated with quercetin(100, 500, 1,000 μM) and then together with various drugs such as 1-methyl-4-phenylpyridinium(MPP+; a free radical generator), 6-hydroxydopamine(6-OHDA; a free radical generator), ammonium chloride(an autophagy inhibitor), and nocodazole(an aggresome inhibitor). Cell viability was determined using a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltertazolium bromide(MTT) assay. Apoptosis was detected by annexin V-fluorescein isothiocyanate and propidium iodide through the use of fluorescence activated cell sorter. α-Synuclein expression was detected by western blot assay and immunohistochemistry. The role of α-synuclein was further studied by knocking out α-synuclein using RNA interference. Cell viability increased at lower concentrations(100 and 500 μM) of quercetin but decreased at higher concentration(1,000 μM). Quercetin exerted neuroprotective effect against MPP+, ammonium chloride and nocodazole at 100 μM. MPP+ induced apoptosis was decreased by 100 μM quercetin. Quercetin treatment increased α-synuclein expression. However, knocking out α-synuclein exerted no significant effect on cell survival. In conclusion, quercetin is neuroprotective against toxic agents via affecting various mechanisms such as apoptosis, autophagy and aggresome. Because α-synuclein expression is increased by quercetin, the role of quercetin as an environmental factor in Parkinson's disease pathogenesis needs further investigation.     

Induction of cross-tolerance between protective effect of morphine and nicotine in 6-hydroxydopamine-induce neurotoxicity in SH-SY5Y human dopaminergic neuroblastoma cells

Purpose: Parkinson’s disease is a progressive neurodegenerative disease characterized by progressive and selective death of dopaminergic neurons. It has been reported that nicotine and morphine have protective roles during neuronal damage in Parkinson’s disease. In addition, the induction of cross-tolerance between their biological effects has been shown in numerous reports.

Methods: Here, we investigated the effects of nicotine and morphine on 6-OHDA-induced neurotoxicity in human neuroblastoma SH-SY5Y cell line as an in vitro model of Parkinson’s disease. Cell damage was induced by 150?μM 6-OHDA and the cells viability was examined by MTT assay. Intracellular reactive oxygen species, calcium level, and mitochondrial membrane potential were determined by fluorescence spectrophotometer method. Biochemical markers of apoptosis were also evaluated by immunoblotting.

Result: The data showed that morphine and nicotine prevent 6-OHDA- induced cell damage and apoptosis. However, the protective effects of nicotine were not observed in chronic morphine-pretreated cells. Morphine had no protective effects in chronic nicotine-incubated cells.

Conclusion: A cross-tolerance between protective effects of morphine and nicotine was occurred in 6-OHDA-induced SH-SY5Y cell toxicity.     

Medial forebrain bundle axotomy during development induces apoptosis in dopamine neurons of the substantia nigra and activation of caspases in their degenerating axons

There is growing evidence that programmed cell death may play a role in degenerative neurologic disease. The caspases are a family of cell death proteins that mediate proteolytic cascades in the death process. Although there is clear evidence that caspases play a role in the destruction of the components of the neuronal soma, it has been controversial whether they play a role in the degeneration of axons that accompanies the death of the cell body. It is important to define the molecular mechanisms of axonal degeneration, because terminal degeneration may occur early in neurodegenerative disease. We have therefore investigated whether caspases play a role in axonal degeneration in the dopaminergic nigrostriatal system following axotomy of the median forebrain bundle during development. We find that this lesion induces apoptosis in midbrain dopaminergic neurons at the level of the cell soma. Concomitantly with this induction of apoptosis, degeneration of dopaminergic axons occurs and is characterized by the formation of axonal swellings and spheroids. Immunohistochemical analysis reveals that the activated form of caspase-3 and a caspase cleavage product of beta-actin are abundantly expressed in these degenerating fibers. We conclude that caspases are activated in degenerating dopaminergic axons as the somata undergo programmed cell death in this model. These results raise the possibility that caspase activation may occur in other programmed cell death contexts for these neurons, and, if this is so, then their inhibition may be a useful therapeutic target.     

Neuroprotective effects of berry fruits on neurodegenerative diseases

Recent clinical research has demonstrated that berry fruits can prevent age-related neurodegenerative diseases and improve motor and cognitive functions. The berry fruits are also capable of modulating signaling pathways involved in inflammation, cell survival, neurotransmission and enhancing neuroplasticity. The neuroprotective effects of berry fruits on neurodegenerative diseases are related to phytochemicals such as anthocyanin, caffeic acid, catechin, quercetin, kaempferol and tannin. In this review, we made an attempt to clearly describe the beneficial effects of various types of berries as promising neuroprotective agents.     

Cell viability and dopamine secretion of 6-hydroxydopamine-treated PC12 cells co-cultured with bone marrow-derived mesenchymal stem cells

In the present study, PC12 cells induced by 6-hydroxydopamine as a model of Parkinson’s Disease, were used to investigate the protective effects of bone marrow-derived mesenchymal stem cells bone marrow-derived mesenchymal stem cells against 6-hydroxydopamine-induced neurotoxicity and to verify whether the mechanism of action relates to abnormal α-synuclein accumulation in cells. Results showed that co-culture with bone marrow-derived mesenchymal stem cells enhanced PC12 cell viability and dopamine secretion in a cell dose-dependent manner. MitoLight staining was used to confirm that PC12 cells co-cultured with bone marrow-derived mesenchymal stem cells demonstrate reduced levels of cell apoptosis. Immunocytochemistry and western blot analysis found the quantity of α-synuclein accumulation was significantly reduced in PC12 cell and bone marrow-derived mesenchymal stem cell co-cultures. These results indicate that bone marrow-derived mesenchymal stem cells can attenuate 6-hydroxydopamine-induced cytotoxicity by reducing abnormal α-synuclein accumulation in PC12 cells.     

Implantation of PC12 cells into the corpus striatum of rats with lesions of the dopaminergic nigrostriatal neurons

PC12 cells, which have the capacity to synthesize and release catecholamines, were implanted into the corpus striatum of adult rats with lesions of the dopaminergic nigrostriatal pathway. PC12 cells survived for 1–2 weeks in the host striatum and degenerated thereafter. The presence of these cells was associated with an attenuation of the apomorphine-induced circling behavior in rats with unilateral nigrostriatal lesions. These findings indicate that cells from a cell line are able, at least temporarily, to survive in the rat brain and to compensate functional deficits caused by lesions of specific neuronal systems. Cell lines might therefore be used for intracerebral grafting instead of neurons derived from fetal brains, if their survival can be prolonged and their proliferation in the host brain prevented.     

共聚物-1对帕金森病模型小鼠多巴胺能神经元的保护作用

目的探讨共聚物-1(Cop-1)免疫或致敏淋巴细胞移植对帕金森病模型小鼠黑质多巴胺(DA)神经元的保护作用。方法选用雄性C57BL/6J小鼠随机分为Cop-1/BSA免疫组、Cop-1/BSA致敏淋巴细胞移植组、MPTP模型组和正常对照组。Cop-1/BSA免疫组在注射MPTP之前10天接受Cop-1/BSA抗原免疫;Cop-1/BSA致敏淋巴细胞移植组动物在MPTP末次注射后,立即接受Cop-1/BSA致敏淋巴细胞移植;MPTP模型组动物仅接受MPTP注射;正常对照组动物仅接受生理盐水注射。MPTP末次注射7天后处死动物,取脑。酪氨酸羟化酶免疫组化及体视学方法定量分析黑质DA神经元数。结果 MPTP注射显著地减少了模型动物黑质DA神经元数量。Cop-1免疫和Cop-1致敏淋巴细胞移植明显增加了MPTP模型动物黑质DA神经元数,对黑质DA神经元有保护作用。BSA免疫或BSA致敏淋巴细胞移植则没有表现出这种保护作用。结论在C57BL/6J小鼠,Cop-1免疫和Cop-1致敏淋巴细胞移植可有效对抗MPTP毒性,保护黑质DA神经元。     

Role of apoptosis and autophagy in the control of cell proliferation in dentate gyrus after hippocampal lesion

研究背景：很多病理情况下都可以引起神经发生（新的神经元产生）,新生细胞的命运和这些疾病的预后有着直接的关系。实验证明脑损伤往往导致海马齿状回神经发生区细胞增殖的增加,新生细胞的数量随着时间的推移逐渐减少,但是新生细胞减少的原因尚不知。阐明这些新生细胞的命运将增加对脑损伤病理过程和治疗手段的理解。 目的：本文研究凋亡和自噬这两种程序性细胞死亡在海马损伤诱导的海马齿状回细胞增殖后新生细胞减少中的作用。 设计、时间和设定：海马齿状回细胞增殖的动物实验于2008年2月至2009年3月在苏州大学医学部神经生物学系进行。 材料：成年雄性SD大鼠通过微量注射海人酸(购自美国Sigma公司)建立海马损伤模型。 方法：5-溴脱氧嘧啶核苷（BrdU）用于标记增殖细胞,海马损伤后齿状回的不同时间点BrdU阳性细胞用免疫组织化学方法鉴定,阳性细胞的数量采用无偏差体视学(Stereology)方法进行定量。凋亡相关蛋白caspase-3、Bcl-2、p53和自噬相关蛋白LC3、Beclin1通过免疫荧光和蛋白质印迹(Western blot）的方法进行检测。 主要结果检测：凋亡和自噬的检测,是在海马损伤后不同时间点,在激光共聚焦显微镜下观察BrdU阳性细胞共表达BrdU/caspase-3、BrdU/LC3和BrdU/Beclin 1。同时, 还用Western blot的方法检测齿状回凋亡相关蛋白和自噬相关蛋白的改变。 结果：定量分析显示海马损伤组在连续3天注射BrdU后的第1天有最多的BrdU阳性细胞,BrdU阳性细胞随着时间的推移逐渐减少。海马颗粒细胞层和门区发现BrdU/cleaved caspase-3双标细胞,海马损伤后的各个时间点未发现BrdU/LC3、BrdU/Beclin 1双标细胞。但Western blot结果显示海马损伤后LC3Ⅱ、Beclin 1、p53的表达上调,pro-caspase-3和Bcl-2的表达下调。 结论：成年大鼠海马损伤后能导致齿状回显著的细胞增殖,这些增殖细胞随着时间的推移逐渐减少,凋亡和自噬可能参与海马损伤后增殖细胞的减少。     

Is X-linked methyl-CpG binding protein 2 a new target for the treatment of Parkinson’s disease？

X-linked methyl-CpG binding protein 2 mutations can induce symptoms similar to those of Parkinson’s disease and dopamine metabolism disorders, but the specific role of X-linked methyl-CpG binding protein 2 in the pathogenesis of Parkinson’s disease remains unknown. In the present study, we used 6-hydroxydopamine-induced human neuroblastoma cell （SH-SY5Y cells） injury as a cell model of Parkinson’s disease. The 6-hydroxydopamine （50 μmol/L） treatment decreased protein levels for both X-linked methyl-CpG binding protein 2 and tyrosine hydroxylase in these cells, and led to cell death. However, overexpression of X-linked methyl-CpG binding protein 2 was able to ameliorate the effects of 6-hydroxydopamine, it reduced 6-hydroxydopamine-induced apoptosis, and increased the levels of tyrosine hydroxylase in SH-SY5Y cells. These findings suggesting that X-linked methyl-CpG binding protein 2 may be a potential therapeutic target for the treatment of Parkinson’s disease.     

The regulatory role of Pin1 in neuronal death

Regulated cell death predominantly involves apoptosis, autophagy, and regulated necrosis. It is vital that we understand how key regulatory signals can control the process of cell death. Pin1 is a cis-trans isomerase that catalyzes the isomerization of phosphorylated serine or threonine-proline motifs of a protein, thereby acting as a crucial molecular switch and regulating the protein functionality and the signaling pathways involved. However, we know very little about how Pin1-associated pathw...     

Verbascoside promotes the regeneration of tyrosine hydroxylase-immunoreactive neurons in the substantia nigra

Tyrosine hydroxylase is a key enzyme in dopamine biosynthesis. Change in tyrosine hydroxylase expression in the nigrostriatal system is closely related to the occurrence and development of Parkinson’s disease. Verbascoside, an extract from Radix Rehmanniae Praeparata has been shown to be clinically effective in treating Parkinson’s disease. However, the underlying mechanisms remain unclear. It is hypothesized that the effects of verbascoside on Parkinson’s disease are related to tyrosine hydroxylase expression change in the nigrostriatal system. Rat models of Parkinson’s disease were established and verbascoside (60 mg/kg) was administered intraperitoneally once a day. After 6 weeks of verbascoside treatment, rat rotational behavior was alleviated; tyrosine hydroxylase mRNA and protein expression and the number of tyrosine hydroxylase-immunoreactive neurons in the rat right substantia nigra were signiifcantly higher than the Parkinson’s model group. These ifndings suggest that the mechanism by which verbascoside treats Parkinson’s disease is related to the regeneration of tyrosine hy-droxylase-immunoreactive neurons in the substantia nigra.     

Panax notoginseng saponins influence on transplantation of neural stem cell-derived dopaminergic neurons in a rat model of Parkinson’s disease *☆

BACKGROUND： Dopaminergic neurons differentiated from neural stem cells have been successfully used in the treatment of rat models of Parkinson＇s disease; however, the survival rate of transplanted cells has been low. Most cells die by apoptosis as a result of overloaded intracellular calcium and the formation of oxygen free radicals.
OBJECTIVE： To observe whether survival of transplanted cells, transplantation efficacy, and dopaminergic differentiation from neural stem cells is altered by Panax notoginseng saponins （PNS） in a rat model of Parkinson＇s disease.
DESIGN, TIME AND SETTING： Cellular and molecular biology experiments with randomized group design. The experiment was performed at the Animal Experimental Center, First Hospital of Sun Yat-sen University from April to October 2007.
MATERIALS： Thirty-two adult, healthy, male Sprague Dawley rats, and four healthy Sprague Dawley rat embryos at gestational days 14-15 were selected. The right ventral mesencephalon was injected with 6-hydroxydopamine to establish a model of Parkinson＇s disease. 6-hydroxydopamine and apomorphine were purchased from Sigma, USA.
METHODS： Neural stem cells derived from the mesencephalon of embryonic rats were cultivated and passaged in serum-free culture medium. Lesioned animals were randomly divided into four groups （n = 8）： dopaminergic neuron, dopaminergic neuron ＋ PNS, PNS, and control. The dopaminergic neuron group was injected with 3 μL cell suspension containing dopaminergic neurons differentiated from neural stem cells. The dopaminergic neurons ＋ PNS group received 3 μ L dopaminergic cell suspension combined with PNS （250 mg/L）. The PNS group received 3 μL PNS （250 mg/L）, and the control group received 3 μL DMEM/F12 culture medium.
MAIN OUTCOME MEASURES： The rats were transcardially perfused with 4% paraformaldehyde at 60 days post-grafting for immunohistochemistry. The rats were intraperitoneally injected with apomorphine （0.5 mg/kg） to induce rotational behavior. RESU     

Optimal concentration of necrostatin-1 for protecting against hippocampal neuronal damage in mice with status epilepticus

Hippocampal neurons undergo various forms of cell death after status epilepticus.Necrostatin-1 specifically inhibits necroptosis mediated by receptor interacting protein kinase 1 (RIP1) and RIP3 receptors.However,there are no reports of necroptosis in mouse models of status epilepticus.Therefore,in this study,we investigated the effects of necrostatin-1 on hippocampal neurons in mice with status epilepticus,and,furthermore,we tested different amounts of the compound to identify the optimal concentration for inhibiting necroptosis and apoptosis.A mouse model of status epilepticus was produced by intraperitoneal injection of kainic acid,12 mg/kg.Different concentrations of necrostatin- 1 (10,20,40,and 80 μM) were administered into the lateral ventricle 15 minutes before kainic acid injection.Hippocampal damage was assessed by hematoxylin-eosin staining 24 hours after the model was successfully produced.Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining,western blot assay and immunohistochemistry were used to evaluate the expression of apoptosis-related and necroptosis-related proteins.Necrostatin-1 alleviated damage to hippocampal tissue in the mouse model of epilepsy.The 40 μM concentration of necrostatin-1 significantly decreased the number of apoptotic cells in the hippocampal CA1 region.Furthermore,necrostatin-1 significantly downregulated necroptosis-related proteins (MLKL,RIP1,and RIP3) and apoptosis-related proteins (cleaved-Caspase-3,Bax),and it upregulated the expression of anti-apoptotic protein Bcl-2.Taken together,our findings show that necrostatin-1 effectively inhibits necroptosis and apoptosis in mice with status epilepticus,with the 40 μM concentration of the compound having an optimal effect.The experiments were approved by the Animal Ethics Committee of Fujian Medical University,China (approval No.2016-032) on November 9,2016.     

Anti-apoptotic effect ofShudipingchan granule in the substantia nigra of rat models of Parkinson’s disease

Levodopa is the gold-standard treatment for Parkinson’s disease. However, although it alleviates the clinical symptoms, it cannot delay the progressive apoptosis of dopaminergic neurons or prevent motor complications in the long term. In the present study, we investigated the effect ofShudipingchan granule on neuronal apoptosis in a rat model of Parkinson’s disease, established by injecting 6-hydroxydopamine into the substantia nigra pars compacta and ventral tegmental area. We then administered levodopa (20 mg/kg intraperitoneally, twice daily) with or withoutShudipingchan granule (7.5 mL/kg intragastrically, twice daily), for 4 weeks. hTe long-term use of levodopa accel-erated apoptosis of nigral cells and worsened behavioral symptoms by activating the extracellular signal-regulated kinase pathway and downstream apoptotic factors. However, administration ofShudipingchan granule with levodopa reduced expression of phosphorylated extracellular signal-regulated kinase 1/2 and Bax, increased tyrosine hydroxylase and Bcl-2, reduced apoptosis in the substantia nigra, and markedly improved dyskinesia. hTese ifndings suggest thatShudipingchan granule suppresses neuronal apoptosis by inhibiting the hyper-phosphorylation of extracellular signal-regulated kinase and downregulating expression of anti-apoptotic genes.Shudipingchan granule, used in combination with levodopa, can effectively reduce the symptoms of Parkinson’s disease.