五味子甲素对MPP^+诱导的SH-SY5Y细胞凋亡的影响北大核心CSCD

目的初步研究不同浓度的五味子甲素(Schisandra A,Sch A)对1-甲基-4-苯基吡啶离子(1-methyl-4-phenylpyridinium ion,MPP^+)引起的SH-SY5Y细胞凋亡的影响。方法体外培养人神经母细胞瘤SH-SY5Y细胞,1 mmol/L MPP^+染毒同时分别给予1、3和5μmol/L Sch A处理48 h,Muse^(TM)细胞分析仪检测凋亡细胞数的变化;hoechst33342染色后激光共聚焦显微镜进一步观察各组细胞形态的改变;Western-blot检测各组细胞中cleaved caspase-3蛋白表达水平的变化。结果与对照组相比,1 mmol/L MPP^+染毒48 h可引起SH-SY5Y细胞凋亡细胞数明显增多;1、3和5μmol/L Sch A干预可明显抑制1mmol/L MPP^+诱导的SH-SY5Y细胞凋亡,且随着Sch A浓度的升高,凋亡细胞数明显减少。Western-blot实验结果显示,MPP^+组细胞中cleaved caspase-3蛋白表达水平明显升高,而Sch A干预组cleaved caspase-3蛋白表达明显降低(P<0.05)。结论 1 mmol/L MPP^+可诱导SH-SY5Y细胞凋亡,而一定浓度的Sch A能有效抑制MPP^+引起的SH-SY5Y细胞凋亡,且该作用可能是通过抑制caspase-3蛋白活化实现的。     

H2O2诱导PC12细胞凋亡的作用机制

目的 探讨H2O2诱导PC12细胞凋亡的作用机制。方法用MTT比色法分析细胞存活率，Hoechst—PI荧光染色和流式细胞仪检测分析细胞凋亡情况；通过RT—PCR和Western blot从mRNA及蛋白水平检测par-4、NF—KB、caspase-3基因表达水平的变化；用比色法检测Caspase-3相对活性。结果（1）用终浓度分别为0～400nmol／L H2O2处理PC12细胞8h，随H2O2浓度从25～400nmol／l。增加，PC12细胞存活率逐渐降低（P〈0．05）：     

姜黄素对MPP~+诱导PC12细胞凋亡的影响

目的观察姜黄素对MPP+诱导的PC12细胞凋亡的影响。方法采用透射电镜,hoechst染色和流式细胞仪(FCM)观察PC12细胞凋亡,间接免疫荧光流式细胞术检测PC12细胞bcl2的表达。结果PC12细胞自然凋亡率为(15±01)%,05mmol·L-1、1mmol·L-1和2mmol·L-1MPP+作用24h后,PC12细胞凋亡率分别为(441±38)%、(549±21)%和(822±26)%;20μmol·L-1和40μmol·L-1姜黄素对PC12细胞作用24h后无明显凋亡诱导作用,但可分别使05mmol·L-1MPP+处理组细胞凋亡率由(441±38)%下降到(341±38)%和(179±15)%(P<001);PC12细胞经20μmol·L-1姜黄素处理24h后,其bcl2表达率由正常对照的(3643±790)%增加到(7673±860)%(P<001)。结论姜黄素可以抑制MPP+诱导的PC12细胞凋亡,其作用机制之一可能与促进bcl2的表达有关。     

抗氧化作用可能是人参皂甙Rg1抗细胞凋亡的机制

目的 :探讨人参皂甙Rg1对MPP+诱导SHSY5Y细胞凋亡的保护作用及其可能的机制。方法 :用吖啶橙溴化乙锭染色观察SHSY5Y细胞凋亡率 ,流式细胞仪检测线粒体跨膜电位及细胞内活性氧 (ROS)水平 ,WesternBlot法检测bcl 2、bax蛋白表达水平。结果 :经 10 μmol·L- 1Rg1预处理后 ,MPP+诱导的SHSY5Y细胞凋亡受到明显的抑制 ,虽然线粒体跨膜电位无明显改变 ,但细胞内ROS下降 ,而bcl 2蛋白表达水平增加 ,bax蛋白表达水平减少。结论 :Rg1可抑制MPP+诱导的SHSY5Y细胞凋亡 ,其作用机制可能是通过清除ROS、调节bcl 2、bax蛋白表达水平起作用。     

灯盏乙素抑制过氧化氢诱导PC12细胞凋亡及机制

目的：观察灯盏乙素对过氧化氢（H2O2）诱导PC12细胞凋亡的抑制作用及其作用机制。方法：采用H2O2诱导PC12细胞凋亡模型，用碘化丙啶（PI）单染和PI／Annexin V双染检测细胞凋亡，用DNA琼脂糖凝胶电泳观察DNA断裂，并采用RT-PCR检测Bcl-2 mRNA表达、荧光光度法检测caspase-3活性。结果：灯盏乙素可以抑制H2O2诱导的膜磷脂酰丝氨酸外翻，增加Bcl-2 mRNA表达，减小caspase-3活性，并降低DNA片段化和细胞凋亡率。结论：灯盏乙素显著抑制H2O2诱导的细胞凋亡，其抗细胞凋亡作用可能与其增加Bcl-2表达、抑制caspase-3活化有关。     

杨梅素诱导人宫颈癌HeLa细胞凋亡及凋亡通路的研究

目的研究杨梅素体外对人宫颈癌HeLa细胞增殖、凋亡及凋亡通路的影响。方法体外培养人宫颈癌HeLa细胞,MTT和SRB法检测细胞增殖抑制率;流式细胞仪检测细胞凋亡,计算机分析细胞周期;Western Blot法检测caspase-3、caspase-9和survivin含量。结果杨梅素对HeLa细胞的体外增殖具有抑制作用,并具有浓度和时间依耐性;杨梅素体外诱导HeLa细胞凋亡,并将细胞周期阻滞在S期;杨梅素促进caspase-3和caspase-9蛋白表达,抑制survivin蛋白表达。结论杨梅素可抑制HeLa细胞的增殖,诱导其凋亡,其凋亡途径同时涉及细胞内途径和细胞外途径。     

紫铆因通过抑制p53信号通路对抗丙酮醛诱导的PC12细胞凋亡

目的探讨紫铆因对丙酮醛诱导的PC12细胞凋亡的影响及作用机制。方法采用不同剂量的紫铆因预处理1 h后,1.5 mmol·L~(-1)丙酮醛诱导PC12细胞凋亡,MTT及LDH比色法分析细胞存活率及细胞毒性;PI及Hoechst 33342双染法分析细胞凋亡及坏死;逆转录PCR检测促凋亡基因p53、caspase-9和抗氧化基因SOD2的表达;免疫印迹法检测p53、caspase-9的蛋白表达。结果不同剂量的紫铆因预处理PC12细胞1 h后,可明显对抗丙酮醛引起的细胞凋亡,提高细胞存活率,减少细胞核固缩、碎裂,抑制促凋亡基因p53、caspase-9的过表达,提高抗氧化基因SOD2的表达。结论紫铆因能明显对抗丙酮醛诱导的PC12细胞凋亡,作用机制与其抗氧化活性,降低促凋亡基因p53、caspase-9的表达有关。     

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.     

天麻素通过抑制细胞凋亡保护谷氨酸诱导的PC12细胞损伤

目的：研究天麻素（Gastrodin）对谷氨酸诱导的大鼠肾上腺嗜铬细胞瘤PC12细胞损伤的影响及可能机制。方法：以谷氨酸建立体外培养PC12细胞损伤模型并采用MTT比色法测定细胞存活率;AO/EB双染法经荧光显微镜观察细胞凋亡形态;采用流式细胞术检测细胞内活性氧含量以及Annexin V/PI染色后的细胞凋亡率;Western blot法检测细胞内Caspase-3蛋白表达。结果：天麻素可明显抑制谷氨酸诱导的PC12细胞凋亡,在0.1～10μmol/L剂量呈一定的量效关系;同时,天麻素可明显抑制谷氨酸引起的活性氧（ROS）的累积,降低谷氨酸诱导的活性Caspase-3蛋白的表达,降低PC12细胞的凋亡率,在0.1～10μmol/L剂量呈量效相关性。结论：在一定剂量范围内,天麻素对谷氨酸损伤的PC12细胞具有保护作用,其机制可能与减少ROS的生成,阻止氧化损伤的发生,抑制Caspase-3途径依赖的细胞凋亡相关。     

Protective effect of verbascoside on 1-methyl-4-phenylpyridinium ion-induced neurotoxicity in PC12 cells

The neuroprotective effects of verbascoside, one of phenylpropanoid glucoside isolated from the Chinese herbal medicine Buddleja officinalis Maxim, on 1-methyl-4-phenylpyridinium ion (MPP(+)) induced apoptosis and oxidative stress in PC12 neuronal cells were investigated. Treatment of PC12 cells with MPP(+) for 48 h induced apoptotic death as determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry, the activation of caspase-3 measured by the caspase-3 activity assay kit, the reduction in mitochondrial membrane potential with laser scanning confocal microscopy and the increase in the extracellular hydrogen peroxide level. Simultaneous treatment with verbascoside markedly attenuated MPP(+)-induced apoptotic death, increased extracellular hydrogen peroxide level, the activation of caspase-3 and the collapse of mitochondrial membrane potential. These results strongly indicate that verbascoside may provide a useful therapeutic strategy for the treatment of oxidative stress-induced neurodegenerative disease such as Parkinson's disease.     

Dexamethasone-induced apoptosis in PC12 cells

Abstract

This study aims to evaluate the cytotoxicity and damage of dexamethasone (DEX) on rat pheochromocytoma (PC12) cells by determining cell viability, Hoechst 33342 staining, mitochondrial depolarization assays, opened mitochondrial permeability transition pores (MPTPs) detection, and measurement of Caspase-3 and Bcl-2 activities. The results show that DEX inhibits PC12 cell growth and decreases their viability in a remarkable dose-dependent manner. Our results also reveal that DEX exposure causes morphologic changes, opening of MPTPs and mitochondrial depolarization, upregulates Caspase-3 expression, and suppresses Bcl-2 expression in PC12 cells. These results suggest that DEX-induced apoptosis may be mediated through mitochondrial dysfunction.     

Antioxidant effect of erythropoietin on 1-methyl-4-phenylpyridinium-induced neurotoxicity in PC12 cells

The neuroprotective effects of erythropoietin on 1-methyl-4-phenylpyridinium (MPP(+))-induced oxidative stress and apoptosis in cultured PC12 cells as well as the underlying mechanism were investigated. Treatment of PC12 cells with MPP(+) caused the loss of cell viability, which was associated with the elevation in apoptotic rate, the formation of reactive oxygen species and the disruption of mitochondrial transmembrane potential. It was also shown that MPP(+) significantly induced upregulation of Bax/Bcl-2 ratio and activation of caspase-3. In contrast, erythropoietin reversed these phenotypes and had its maximum protective effect at 1 U/ml. The effect of erythropoietin was mediated by the phosphatidylinositol 3-kinase (PI3K) signaling pathway since erythropoietin failed to rescue cells from MPP(+) insult in the presence of the PI3K inhibitor, LY 294002. In addition, the downstream effector of PI3K, Akt, was activated by erythropoietin, and Akt activation was inhibited by LY 294002. Furthermore, the effect of erythropoietin on reactive oxygen species levels was also blocked by LY 294002. These results show that erythropoietin may provide a useful therapeutic strategy for the treatment of oxidative stress-induced neurodegenerative diseases such as Parkinson disease.     

Melatonin attenuates 1-methyl-4-phenylpyridinium-induced PC12 cell death

Aim: To explore the effect of melatonin on PC 12 cell death induced by 1-methyl-4-phenylpyridinium (MPP^ ). Methods: MTT assay, lactate dehydrogenase (LDH) efflux assay, and immunohistochemistry methods were used to measure neurotoxicity of PC 12 cells treated acutely with MPP^ in low glucose and high glucose conditions, and to assess the neuroprotective effect of melatonin on PC 12 cell death induced by MPP^ .Results: In a low glucose condition, MPP^ significantly induced PC 12 cell death, which showed time and concentration dependence. In a serum-free low glucose condition, the percentages of viability of cells treated with MPP^ for 12, 24, 48, 72, and 96 h were 85.1%, 75.4%, 64.9%, 28.15%, and 9%, respectively. The level of LDH in the culture medium increased and tyrosine hydroxylase positive (TH^ ) cell count decreased. However, in a serum-free high glucose condition, MPP^ did not significantly induce PC12 cell death compared with control at various concentrations and time regimens. When the cells were preincubated with melatonin 250 μmol/L for 48, 72, and 96 h in a serum-free low glucose condition, cell survival rate significantly increased to 78.1%, 58.8%, and 31.6%, respectively. Melatonin abolished the LDH leakage of cells treated with MPP^ and increased TH^ cells count. Conclusion: MPP^ caused concentration-dependent PC12 cell death. The level of glucose was an important factor to MPP^ induced dopaminergic PC 12 cell death. Low glucose level could potentiate MPP^ toxicity, while high glucose level could reduce the toxicity. In addition, melatonin attenuated PC12 cell death induced by MPP^ .     

Piperine inhibition of 1-methyl-4-phenylpyridinium-induced mitochondrial dysfunction and cell death in PC12 cells

The effect of alkaloid piperine against the toxicity of 1-methyl-4-phenylpyridinium (MPP(+)) in differentiated PC12 cells was assessed. Piperine treatment revealed a differential effect on the cytotoxicity of MPP(+) and had its maximum inhibitory effect at 1 microM. The addition of piperine (0.5-10 microM) significantly reduced the MPP(+)-induced nuclear damage, mitochondrial membrane permeability changes, formation of reactive oxygen species and depletion of GSH. In contrast, piperine at 50-100 microM showed cytotoxicity and exhibited an additive effect against the MPP(+) toxicity. The results indicate that piperine had a differential effect on the cytotoxicity of MPP(+) depending on concentration. Piperine at low concentrations may reduce the MPP(+)-induced viability loss in PC12 cells by suppressing the changes in the mitochondrial membrane permeability, leading to the release of cytochrome c and subsequent activation of caspase-3. The effects may be ascribed to its inhibitory action on the formation of reactive oxygen species and depletion of GSH.     

p53-mediated ferroptosis is required for 1-methyl-4-phenylpyridinium-induced senescence of PC12 cells

Parkinson's disease (PD) is characterized by the loss of dopaminergic neurons in the substantia nigra and striatum. Aging is the most important risk factor of PD. Ferroptosis is an iron-dependent form of cell death associated with PD. However, it is not clear whether ferroptosis accelerates PD by promoting cellular senescence. This study investigated the mechanism of 1-methyl-4-phenylpyridinium (MPP⁺) -induced PC12 cells injury. We found that MPP⁺ induced cell senescence with increased β-galactosidase activity and the expression of p53, p21 and p16 activation in cells. In addition, MPP⁺ treatment showed smaller mitochondria and increased membrane density, downregulation of ferritin heavy chain 1 expression and upregulation of acyl-CoA synthetase long chain family member 4 expression, and enhanced levels of oxidative stress, which were important characteristics of ferroptosis. Ferrostatin-1 (Fer-1), a ferroptosis inhibitor, was tested to eliminate MPP⁺-induced cell senescence. Fer-1 downregulated the expression of p53 and upregulated the expression of solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase-4 (GPX4) in MPP⁺-induced ferroptosis. Inhibition of p53 eliminated cell senescence by upregulation the expression of of SLC7A11 and GPX4. Thus, these results suggest that MPP⁺ induces senescence in PC12 cells via the p53/ SLC7A11/ GPX4 signaling pathway in the ferroptosis regulation mechanism.     

1-methyl-4-phenylpyridinium-induced alterations of glutathione status in immortalized rat dopaminergic neurons

Decreased glutathione levels associated with increased oxidative stress are a hallmark of numerous neurodegenerative diseases, including Parkinson's disease. GSH is an important molecule that serves as an anti-oxidant and is also a major determinant of cellular redox environment. Previous studies have demonstrated that neurotoxins can cause changes in reduced and oxidized GSH levels; however, information regarding steady state levels remains unexplored. The goal of this study was to characterize changes in cellular GSH levels and its regulatory enzymes in a dopaminergic cell line (N27) following treatment with the Parkinsonian toxin, 1-methyl-4-phenylpyridinium (MPP(+)). Cellular GSH levels were initially significantly decreased 12 h after treatment, but subsequently recovered to values greater than controls by 24 h. However, oxidized glutathione (GSSG) levels were increased 24 h following treatment, concomitant with a decrease in GSH/GSSG ratio prior to cell death. In accordance with these changes, ROS levels were also increased, confirming the presence of oxidative stress. Decreased enzymatic activities of glutathione reductase and glutamate-cysteine ligase by 20-25% were observed at early time points and partly account for changes in GSH levels after MPP(+) exposure. Additionally, glutathione peroxidase activity was increased 24 h following treatment. MPP(+) treatment was not associated with increased efflux of glutathione to the medium. These data further elucidate the mechanisms underlying GSH depletion in response to the Parkinsonian toxin, MPP(+).     

1-甲基-4-苯基吡啶离子诱导大鼠肾上腺嗜铬细胞瘤PC12细胞发生铁死亡的实验观察

目的 进行1-甲基-4-苯基吡啶离子(1-methyl-4-phenyl pyridine,MPP+)诱导大鼠肾上腺嗜铬细胞瘤PC12细胞铁死亡(Ferroptosis)的研究.方法 采用噻唑蓝法(MTT)检测细胞存活率和筛选铁死亡抑制剂(Ferrostatin-1)的最佳作用浓度;倒置显微镜观察Ferrostatin-1对PC12细胞的保护作用;MDC染色检测细胞自噬;ELISA法检测caspase-3的酶活性;流式细胞术检测活性氧ROS.结果 1 mmol·L-1 MPP+对PC12细胞有明显抑制作用;5 μmol·L-1 Ferrostatin-1能够明显提高PC12细胞的存活率;倒置显微镜观察结果表明Ferrostatin-1预保护后,PC12细胞损伤明显减少;MDC染色检测细胞自噬和ELISA法检测caspase-3的酶活性结果显示Ferrostatin-1对MPP+诱导的PC12细胞自噬和凋亡的保护作用不明显;ROS活性氧检测结果显示ROS在胞内增加,可能发生氧化应激,加Ferrostatin-1后ROS荧光强度减弱.结论 Ferroptosis能够显著抑制MPP+诱导的PC12细胞损伤,且Ferrostatin-1对细胞的自噬和凋亡作用不明显,推测出MPP+诱导PC12细胞的损伤可能有Ferroptosis的存在.