类叶升麻苷抗鱼藤酮致SH-SY5Y细胞损伤机制的研究

目的研究类叶升麻苷抗鱼藤酮致多巴胺能神经元SH-SY5Y细胞损伤,对帕金森病相关蛋白Parkin、α-突触核蛋白(α-Synuclein,α-Syn)表达的影响,探讨类叶升麻苷抗细胞损伤的分子机制。方法化学比色法测定细胞培养液乳酸脱氢酶(lactate dehydrogenase,LDH)活性,蛋白质印迹法(Western blot)检测Parkin、α-Syn的表达,免疫荧光法检测SH-SY5Y细胞α-Syn分布。结果①类叶升麻苷(10,20或40mg.L-1)可明显降低鱼藤酮诱导的SH-SY5Y细胞乳酸脱氢酶(LDH)的释放;②0.5μmol.L-1的鱼藤酮处理SH-SY5Y细胞48h能引起Parkin蛋白的明显降解及α-Syn蛋白二聚体增加;③预先用类叶升麻苷(10,20或40mg.L-1)处理细胞,能够有效减少鱼藤酮诱导的Parkin蛋白的降解,呈浓度依赖性;并能够抑制鱼藤酮诱导的α-Syn蛋白二聚体增加及α-Syn阳性细胞数增加。结论类叶升麻苷对鱼藤酮致SH-SY5Y细胞损伤具有神经保护作用,其作用机制可能与减少Parkin蛋白的降解和抑制α-Syn蛋白的二聚体形成有关。     

野生型DJ-1基因在体外培养SH-SY5Y细胞中高表达对氧化损伤的抑制作用*

目的:研究帕金森病相关基因野生型DJ-1高表达对鱼藤酮及过氧化氢致多巴胺神经元SH-SY5Y细胞氧化损伤的保护作用及机制。方法:将pcDNA3-FLAG-DJ-1质粒转染进入SH-SY5Y细胞,采用Western blot分析观察DJ-1在细胞内的表达,以2,7-二氯荧光黄双乙酸盐(DCFH-DA)作为探针,用流式细胞仪检测鱼藤酮诱导的活性氧水平,以MTT法检测过氧化氢损伤的细胞存活率变化。结果:野生型DJ-1被转染进入SH-SY5Y细胞中,并能高表达。野生型DJ-1的高表达可减少活性氧的生成,0.5μmo.lL-1浓度的鱼藤酮处理细胞48 h后,细胞内存在大量活性氧,M2期细胞明显减少(转染野生型DJ-1的SH-SY5Y细胞71.60%与未转染DJ-1的SH-SY5Y细胞89.19%相比)。并且可以抑制过氧化氢导致的细胞存活率下降,过氧化氢处理1 h后,野生型DJ-1转染的细胞存活率明显高于未转染者,过氧化氢浓度为0.1,0.2和0.5 mmol.L-1,细胞存活率分别由77.71%,66.28%和39.08%上升至93.01%,83.96%和60.15%。结论:野生型DJ-1基因在体外培养SH-SY5Y细胞中高表达对氧化损伤具有抑制作用,该作用可能与降低细胞内活性氧水平有关。     

毛蕊花苷对MPP~+诱导的SHSY5Y细胞凋亡的保护作用

目的观察肉苁蓉提取物毛蕊花苷对MPP+诱导的SHSY5Y细胞损伤的影响。方法用MTT法检测细胞存活率,以流式细胞仪检测细胞内活性氧的产生和线粒体膜电位的变化,以及细胞凋亡的发生,并用荧光酶标仪测定caspase-3的活性,蛋白印迹测定Bcl-2的表达水平。结果200μmol·L-1MPP+处理细胞24h降低细胞的存活率;诱导细胞发生凋亡,凋亡率达38.9%;细胞内活性氧水平及caspase-3的活性升高;而线粒体膜电位却明显降低。而预先给予0.1、1或者10mg·L-1浓度的毛蕊花苷处理细胞12h,可提高细胞存活率;流式细胞仪检测凋亡率分别降低到29.5%,15.3%和8.6%,而且细胞内活性氧的水平明显降低,并可逐渐恢复线粒体的高能量状态;caspase-3的活性不断降低,Bcl-2的表达水平增高,并呈现一定的剂量依赖性。结论毛蕊花苷能抑制MPP+诱导的SHSY5Y细胞凋亡,其神经细胞保护作用可能与其降低细胞内活性氧水平,维持线粒体膜电位的高能状态和抑制caspase-3的活性有关。     

松果菊苷对TNFα诱导的SH-SY5Y细胞凋亡的保护作用

目的　探讨肉苁蓉提取物松果菊苷对TNFα诱导的SH SY5Y细胞凋亡的保护作用。方法　用MTT法检测细胞存活率,DNA琼脂糖凝胶电泳和流式细胞仪检测细胞凋亡的发生,以激光共聚焦显微镜荧光染色法检测细胞内活性氧的产生和线粒体膜电位的变化,并用荧光酶标仪测定caspase 3的活性。结果　100μg·L-1 TNFα处理细胞 36h显著降低细胞的存活率;诱导细胞发生凋亡,凋亡率达37%;细胞内活性氧水平及caspase 3的活性升高;而线粒体膜电位却明显降低,红 /绿荧光强度的比值由正常的 5 97降低为 0 35左右。而预先给予 1, 10或者 100mg·L-1浓度的松果菊苷处理细胞 2h,可提高细胞存活率;并可有效抑制DNAladder的发生;流式细胞仪检测凋亡率分别降低到25 9%, 18 3% 和 8 2%;激光共聚焦显微镜结果显示松果菊苷可明显抑制细胞内活性氧产生;并可逐渐恢复线粒体的高能量状态;caspase 3的活性不断降低,并呈现了一定的剂量依赖性。结论　松果菊苷能抑制TNFα诱导的SH SY5Y细胞凋亡,其神经细胞保护作用可能与降低细胞内活性氧水平,抑制caspase 3的活性和维持线粒体膜电位的高能状态有关。     

鱼藤素对SH-SY5Y神经母细胞瘤细胞凋亡的诱导作用

目的研究鱼藤素对SH-SY5Y细胞凋亡的诱导作用。方法鱼藤素(0、0.625、1.25、2.5、5、10、20μmol·L~(-1))处理SH-SY5Y细胞24、48、72 h后,CCK-8法测定细胞存活率。鱼藤素(0、8、20、50μmol·L~(-1))处理SH-SY5Y细胞24 h,光镜下及AO/EB双染分别观察细胞形态和凋亡形态,流式细胞术检测细胞凋亡率,DCFH-DA荧光探针法检测细胞活性氧水平,分光光度法检测caspase-3活化程度。结果鱼藤素对SH-SY5Y细胞存活率呈时间和浓度依赖性抑制作用,作用24、48、72 h的IC50值分别为(26.07±2.18)、(18.33±0.94)、(12.5±1.49)μmol·L~(-1)。鱼藤素处理24 h后,细胞凋亡率、细胞活性氧水平明显上升(P<0.05),caspase-3活化程度升高,且三者均有浓度-效应特征。结论鱼藤素可抑制SH-SY5Y细胞存活,诱导细胞凋亡,其机制可能与升高活性氧水平和活化caspase-3相关。     

红参水提物对Aβ25-35诱导SH-SY5Y细胞凋亡的保护作用

目的 探讨红参水提物对Aβ25-35诱导人神经瘤母细胞SH-SY5Y细胞凋亡的保护作用.方法 用Aβ25-35处理SH-SY5Y细胞,模拟阿尔茨海默病患者脑内神经元的病理损伤模型,以不同浓度的红参水提物进行干预;用倒置显微镜观察其形态学的变化;MTT法测定细胞的存活率;流式细胞技术检测细胞的凋亡率以及线粒体膜电位的变化.结果 50 μmol·L-1Aβ25-35诱导SH-SY5Y细胞72 h后,细胞变圆、聚集,其存活率为39.26%土3.16%、凋亡率为37.30%±0.69%,线粒体红绿荧光强度比值为0.45±0.10;而Aβ25-35诱导的SH-SY5Y细胞与不同浓度(1、5、10 mg·ml-1)红参水提物同时孵育后,明显减少了细胞损伤,升高了细胞存活率、降低了凋亡率,并升高了线粒体红绿荧光强度比值.结论 红参水提物对Aβ25-35诱导的SH-SY5Y细胞凋亡有显著的保护作用.     

镧对原代神经元存活率和细胞内活性氧含量的影响

目的观察不同浓度氯化镧对大脑皮层神经元存活率和细胞内活性氧含量的影响。方法体外培养大鼠大脑皮层神经元,神经元特异性烯醇化酶(NSE)免疫细胞化学法鉴定神经元纯度,四唑蓝比色实验(MTT)检测神经元存活率,DCFH-DA荧光探针法检测细胞内活性氧含量。结果镧处理组神经元存活率降低,其中1.0 mmol/L组细胞存活率接近50%;细胞内活性氧含量升高,并呈现剂量-反应关系。结论镧可使体外培养的大鼠大脑皮层神经元存活率降低,其机制可能与细胞内活性氧水平升高有关。     

6-羟基-1H-吲唑抑制Tau磷酸化对MPP~+诱导凋亡的SH-SY5Y细胞保护作用的研究

目的研究6-羟基-1H-吲唑通过抑制Tau磷酸化对MPP+诱导凋亡的SH-SY5Y细胞的保护作用。方法体外培养人神经母细胞瘤细胞SH-SY5Y,以MPP+诱导SH-SY5Y细胞凋亡作为帕金森病的细胞模型。MTT分析法检测提前2 h加入6-羟基-1H-吲唑对细胞的保护作用;Hoechst 33258荧光染色法检测神经元凋亡情况;免疫细胞化学方法检测多巴胺能神经元内Tau的磷酸化水平。结果 200μmol·L-1MPP+可以使SH-SY5Y细胞存活率下降至(47.80±0.84)%(P<0.01),并且升高Tau磷酸化水平,出现典型的凋亡。而6-羟基-1H-吲唑抑制MPP+对SH-SY5Y细胞的毒性,并通过抑制Tau蛋白过度磷酸化而减少神经元凋亡,使TH-阳性细胞数目增加。结论 6-羟基-1H-吲唑可以通过抑制Tau磷酸化而对MPP+诱导凋亡的SH-SY5Y细胞发挥保护作用,提示Tau蛋白可能可以作为药物治疗帕金森等神经退行性疾病的新靶点。     

姜黄素对人神经母细胞瘤细胞作用的体外试验研究

目的:研究姜黄素对人神经母细胞瘤细胞SH-SY5Y凋亡与侵袭能力的影响。方法:人神经母细胞瘤细胞SH-SY5Y与不同浓度(1.25、2.5、5.0、10.0、15.0、20.0μmol.L-1)的姜黄素共孵育48h。MTT法检测细胞存活率;用流式细胞仪和Hoechst33258染色检测细胞凋亡,并观察细胞形态学改变;应用Transwell细胞侵袭试验检测细胞侵袭能力。结果:各浓度姜黄素能够不同程度地抑制人神经母细胞瘤细胞SH-SY5Y的生长,其对SH-SY5Y细胞的半数抑制浓度为15μmol.L-1,随着姜黄素浓度的增加,SH-SY5Y细胞数量逐渐减少;姜黄素对SH-SY5Y细胞有促凋亡和减弱细胞侵袭能力的作用。结论:姜黄素治疗神经母细胞瘤具有应用价值。     

低浓度利福平对鱼藤酮介导的帕金森病细胞模型SH-SY5Y细胞的保护作用

目的 探讨低浓度利福平对鱼藤酮诱导的人神经母细胞瘤细胞株(SH-SY5Y)细胞的影响.方法 鱼藤酮损伤SH-SY5Y细胞建立帕金森病细胞模型,光学显微镜下观察细胞形态,MTT法检测细胞活性,流式细胞术检测活性氧(ROS)和细胞凋亡率,RT-PCR法检测α-突触核蛋白mRNA.结果 经利福平1、10、100 nmol/L预处理后,三个利福平组细胞ROS含量、α-突触核蛋白mRNA以及细胞凋亡率均低于鱼藤酮损伤组(P＜0.01).结论 利福平具有抗氧化作用,能降低细胞α-突触核蛋白mRNA水平,并对细胞有保护作用.     

Activation of c-Jun N-terminal protein kinase is a common mechanism underlying paraquat- and rotenone-induced dopaminergic cell apoptosis.

Parkinson's disease (PD) is characterized by selective loss of dopaminergic neurons in the substantia nigra of the brain. Although the underlying causes are not well characterized, epidemiological studies suggest an elevated risk of PD with occupational pesticide exposure. Here, we utilized pheochromocytoma (PC) 12 and SH-SY5Y cells as well as rat primary cultured dopaminergic neurons to investigate mechanisms for dopaminergic cell death induced by paraquat and rotenone, pesticides that are used to model PD in rodents. Both paraquat and rotenone induce selective loss of dopaminergic neurons in primary cultures. We discovered that paraquat induces apoptosis in PC12 cells but not in SH-SY5Y cells, while rotenone exposure causes apoptosis in SH-SY5Y cells but not in PC12 cells. The selective ability of paraquat and rotenone to induce apoptosis in different cell lines correlates with their ability to activate c-Jun N-terminal protein kinase (JNK) and p38 mitogen-activated protein kinases. Furthermore, JNK and p38 are required for rotenone-induced apoptosis in SH-SY5Y cells (K. Newhouse et al., 2004, Toxicol. Sci. 79, 137-146) as well as primary neurons, and for paraquat-induced apoptosis in PC12 cells. However, JNK but not p38 plays a role in paraquat-induced loss of primary cultured dopaminergic neurons. Our data identify JNK activation as a common mechanism underlying dopaminergic cell death induced by both paraquat and rotenone in model cell lines and primary cultures.     

Effect of fraxetin and myricetin on rotenone-induced cytotoxicity in SH-SY5Y cells: comparison with N-acetylcysteine

The purpose of this study was to investigate the potential neuroprotective effects of myricetin (flavonoid) and fraxetin (coumarin) on rotenone-induced apoptosis in SH-SY5Y cells, and the possible signal pathway involved in a neuronal cell model of Parkinson's disease. These two compounds were compared to N-acetylcysteine. The viability of cells was assessed by 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), and cytotoxicity was assayed by lactate dehydrogenase (LDH) released into the culture medium. Parameters related to apoptosis, such as caspase-3 activity, the cleavage of poly(ADP-ribose) polymerase and the levels of reactive oxygen species were also determined. Rotenone caused a time- and dose-dependent decrease in cell viability and the degree of LDH release was proportionally to the effects on cell viability. Cells were pretreated with fraxetin, myricetin and N-acetylcysteine at different concentrations for 30 min before exposure to rotenone. Cytotoxicity of rotenone (5 microM) for 16 h was significantly diminished as well as the release of LDH into the medium, by the effect of fraxetin, myricetin and N-acetylcysteine, with fraxetin (100 microM) and N-acetylcysteine (100 microM) being more effective than myricetin (50 microM). Rotenone-induced apoptosis in SH-SY5Y cells was detected by an increase in caspase-3 activity and in the cleavage of poly(ADP-ribose) polymerase. After exposing these cells to rotenone, a significant increase in reactive oxygen species preceded apoptotic events. Fraxetin (100 microM) and N-acetylcysteine (100 microM) not only reduced rotenone-induced reactive oxygen species formation, but also attenuated caspase-3 activity and poly(ADP-ribose) polymerase cleavage at 16 h against rotenone-induced apoptosis. The effect of fraxetin in both experiments was similar to that of N-acetylcysteine. These results demonstrated the protective action of fraxetin and suggest that it can reduce apoptosis, possibly by decreasing free radical generation in SH-SY5Y cells. Myricetin at 100 microM was without any preventive effect.     

Rotenone-induced apoptosis is mediated by p38 and JNK MAP kinases in human dopaminergic SH-SY5Y cells.

Rotenone is a naturally derived pesticide that has recently been shown to evoke the behavioral and pathological symptoms of Parkinson's disease in animal models. Though rotenone is known to be an inhibitor of the mitochondrial complex I electron transport chain, little is known about downstream pathways leading to its toxicity. We used human dopaminergic SH-SY5Y cells to study mechanisms of rotenone-induced neuronal cell death. Our results suggest that rotenone, at nanomolar concentrations, induces apoptosis in SH-SY5Y cells that is caspase-dependent. Furthermore, rotenone treatment induces phosphorylation of c-Jun, the c-Jun N-terminal protein kinase (JNK), and the p38 mitogen activated protein (MAP) kinase, indicative of activation of the p38 and JNK pathways. Importantly, expression of dominant interfering constructs of the JNK or p38 pathways attenuated rotenone-induced apoptosis. These data suggest that rotenone induces apoptosis in the dopaminergic SH-SY5Y cells that requires activation of the JNK and p38 MAP kinases and caspases. These studies provide insights concerning the molecular mechanisms of rotenone-induced apoptosis in neuronal cells.     

Mitochondrial complex I inhibitor rotenone inhibits and redistributes vesicular monoamine transporter 2 via nitration in human dopaminergic SH-SY5Y cells

Parkinson's disease is a progressive neurodegenerative disorder characterized by selective degeneration of nigrostriatal dopaminergic neurons. Long-term systemic mitochondrial complex I inhibition by rotenone induces selective degeneration of dopaminergic neurons in rats. We have reported dopamine redistribution from vesicles to the cytosol to play a crucial role in selective dopaminergic cell apoptosis. In the present study, we investigated how rotenone causes dopamine redistribution to the cytosol using an in vitro model of human dopaminergic SH-SY5Y cells. Rotenone stimulated nitration of the tyrosine residues of intracellular proteins. The inhibition of nitric-oxide synthase or reactive oxygen species decreased the amount of nitrotyrosine and attenuated rotenone-induced apoptosis. When we examined the intracellular localization of dopamine immunocytochemically using anti-dopamine/vesicular monoamine transporter 2 (VMAT2) antibodies and quantitatively using high-performance liquid chromatography, inhibiting nitration was found to suppress rotenone-induced dopamine redistribution from vesicles to the cytosol. We demonstrated rotenone to nitrate tyrosine residues of VMAT2 using an immunocytochemical method with anti-nitrotyrosine antibodies and biochemically with immunoprecipitation experiments. Rotenone inhibited the VMAT2 activity responsible for the uptake of dopamine into vesicles, and this inhibition was reversed by inhibiting nitration. Moreover, rotenone induced the accumulation of aggregate-like formations in the stained image of VMAT2, which was reversed by inhibiting nitration. Our findings demonstrate that nitration of the tyrosine residues of VMAT2 by rotenone leads to both functional inhibition and accumulation of aggregate-like formations of VMAT2 and consequently to the redistribution of dopamine to the cytosol and apoptosis of dopaminergic SH-SY5Y cells.     

Intracellular dopamine oxidation mediates rotenone-induced apoptosis in PC12 cells

Aim: To study the role of dopamine (DA) in rotenone-induced neurotoxicity in PC12 cells. Methods: Cell viability was assessed by detecting the leakage of lactate dehydrogenase (LDH) into the medium. Apoptosis rate was measured by flow cytometry. Caspase-3-1ike activity was measured by fluorescence assay using the probe Ac-DEVD-AMC. The level of intracellular hydrogen peroxide and other peroxides in PC12 cells were quantified by loading cells with 2‘-7‘-Dichlorodihydrofluorescein diacetate (DCFH-DA) in fluorescence assay. Lactic acid was measured spectrophotometrically. The DA levels in PC 12 cells weredetermined by HPLC-ECD. Results: A 48-h incubation of PC 12 cells with rotenone caused an apoptotic cell death and elevated intracellular reactive oxygen species (ROS) and lactic acid accumulation. Intracellular DA depletion with reserpine significantly attenuated rotenone-induced ROS accumulation and apoptotic cell death. No change was found in rotenone-induced ROS accumulation when cells were co-treated with deprenyl. Brief treatment with reserpine at the end of rotenone treatment had no effect on rotenone-induced neurotoxicity. However, when cells were first incubated with deprenyl, a monoamine oxidase-B inhibitor for 30 min then co-incubated with rotenone plus deprenyl, a brief treatment with reserpine enhanced cell injury. Conclusion: Rotenone-inducedapoptosisinPC12 cells was mediated by intracellular dopamine oxidation.     

PACAP27抑制鱼藤酮诱导细胞凋亡的实验研究

目的探讨垂体腺苷酸环化酶激活肽27(PACAP27)对鱼藤酮诱导的PC12细胞损伤的保护作用。方法诱导分化后的PC12细胞,经不同浓度的鱼藤酮处理后,观察其形态改变;四甲基偶氮唑盐(MTT)法检测细胞活性及代谢状态;磷脂酰丝氨酸外翻法(AnnexinV)检测细胞凋亡,流式细胞术检测细胞凋亡率。结果经鱼藤酮处理24h后PC12细胞活性明显下降,且呈剂量依赖性(P<0.01);PACAP27(10-12～10-7mol·L-1)对鱼藤酮诱导的细胞凋亡具有明显的抑制作用;与鱼藤酮处理组(250nmol·L-1)相比,PACAP27保护组(10-8mol·L-1)AnnexinV和碘化丙啶(propidiumiodide,PI)呈双阳性的晚期凋亡细胞数明显减少;流式细胞仪结果显示,PACAP27可明显减少凋亡细胞的比值,提高细胞的生存率(P<0.01);而PACAP/VIPⅠ型受体拮抗剂PACAP627可逆转这一效应。结论PACAP27可通过PAC1受体介导对鱼藤酮诱导的细胞凋亡进行有效抑制。     

D2/D3受体激动药罗匹尼罗对抗鱼藤酮介导多巴胺能细胞凋亡的研究

目的:探讨D2/D3多巴胺受体激动药罗匹尼罗对多巴胺能细胞是否具有抗凋亡作用并研究其机制。方法:使用多巴胺能细胞株SH-SY5Y,以高剂量呼吸链抑制药鱼藤酮诱导细胞凋亡建立细胞凋亡模型。通过Hoechst染色观察并计数凋亡的细胞,应用免疫印迹(Westernblot)方法检测促凋亡基因caspase 9, cleaved caspase 9,cleaved caspase 3,PARP,cleaved PARP的表达。结果:高剂量鱼藤酮处理细胞24h后其凋亡比例明显升高,罗匹尼罗(10~(-5),10~(-4)mol·L~(-1))预处理2h能显著减少细胞凋亡的比例。免疫印迹方法显示10~(-4)mol·L~(-1)罗匹尼罗预处理2h能减少caspase 9,caspase 3,PARP的剪切。结论:罗匹尼罗能有效抑制鱼藤酮诱导细胞凋亡,其机制可能是通过抑制内源性通路中caspase 9剪切而实现的。     

Paullinia cupana Mart. var. Sorbilis protects human dopaminergic neuroblastoma SH-SY5Y cell line against rotenone-induced cytotoxicity

Paullinia cupana Mart. var. Sorbilis, commonly known as Guaraná, is a Brazilian plant frequently cited for its antioxidant properties and different pharmacological activities on the central nervous system. The potential beneficial uses of Guaraná in neurodegenerative disorders, such as in Parkinson's disease (PD), the pathogenesis of which is associated with mitochondrial dysfunction and oxidative stress, has not yet been assessed. Therefore, the main aim of the present study was to evaluate if an extract of commercial powdered seeds of Guaraná could protect human dopaminergic neuroblastoma SH-SY5Y cell line against rotenone-induced cytotoxicity. Two concentration of Guaraná dimethylsulfoxide extract (0.312 and 0.625 mg/mL) were added to SH-SY5Y cells treated with 300 nM rotenone for 48 h, and the cytoprotective effects were assessed by means of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, measuring lactate dehydrogenase (LDH) levels, and analyzing nuclear integrity with Hoechst33258 stain. Results showed that the addition of Guaraná extract significantly increased the cell viability of SH-SY5Y cells treated with rotenone, in a dose-dependent manner. On the other hand, LDH levels were significantly reduced by addition of 0.312 mg/mL of Guaraná, but unexpectedly, no changes were observed with the higher concentration. Moreover, chromatin condensation and nuclear fragmentation were significantly reduced by addition of any of both concentrations of the extract. The results obtained in this work could provide relevant information about the mechanisms underlying the degeneration of dopaminergic neurons in PD and precede in vivo experiments. Further studies are needed to investigate which active constituent is responsible for the cytoprotective effect produced by Paullinia cupana.