芍药苷对H2O2诱导SH-SY5Y神经细胞损伤的保护作用

目的 研究芍药苷对过氧化氢（H₂O₂）诱导人神经瘤母细胞（SH-SY5Y）凋亡的保护作用及其机制。方法 制备H₂O₂诱导的氧化应激损伤模型。相差显微镜观察SH-SY5Y细胞形态的变化;CCK-8法测定细胞存活率;Hoechst 33258染色法观察细胞凋亡;碘化丙啶染色、流式细胞仪检测细胞周期;2′, 7′-二氯荧光素二乙酸盐（DCFH-DA）法检测细胞内活性氧（ROS）;INT显色反应法测定乳酸脱氢酶（LDH）的量;ELISA法检测8-羟基脱氧鸟苷（8-OHdG）的量;caspase-3催化特异性底物反应检测caspase-3活性。结果 与对照组相比,200 μmol/L H₂O₂作用SH-SY5Y细胞24 h,使细胞存活力显著下降（P＜0.01）,细胞凋亡率上升（P＜0.01）,增殖指数（PI）降低（P＜0.05）,8-OHdG的量上升（P＜0.01）,LDH释放量和细胞内ROS量增加（P＜0.01）,caspase-3活性增强（P＜0.01）。与H₂O₂损伤组相比,芍药苷终浓度为20～40 μmol/L,可浓度相关地减轻H₂O₂诱导的SH-SY5Y细胞上述指标的变化（P＜0.05）;芍药苷10 μmol/L组细胞PI、LDH和8-OHdG量未有明显改观,但能显著减轻H₂O₂诱导的SH-SY5Y细胞毒性、ROS和caspase-3活性（P＜0.05）。结论 芍药苷对H₂O₂诱导SH-SY5Y细胞损伤具有显著保护作用,该作用可能与其清除ROS、减轻DNA氧化损伤、抑制细胞凋亡的caspase通路激活和调节细胞周期有关。     

过氧化氢诱导PC12细胞凋亡及芍药苷的保护作用

 目的探讨过氧化氢诱导PC12细胞凋亡及芍药苷保护作用的可能机制。方法MTT测定细胞存活率,流式细胞仪测定细胞凋亡率,DCFH-DA为细胞内荧光探针,测定细胞内ROS浓度,流式细胞仪检测线粒体跨膜电位。结果200μmol·L^-1H₂O₂可诱导PC12细胞凋亡,细胞内ROS浓度增加,细胞线粒体跨膜电位明显下降。预先经过0.1,1和10μmol·L^-1浓度的芍药苷处理后,H₂O₂诱导的PC12细胞凋亡明显减少,同时明显减弱H₂O₂对细胞内ROS浓度和线粒体跨膜电位的影响。结论芍药苷可抑制过氧化氢诱导PC12细胞凋亡,其作用机制可能与其抑制细胞内ROS累积,稳定细胞线粒体跨膜电位有关。     

总丹酚酸和银杏叶提取物对血管平滑肌细胞保护作用的比较

 目的对丹参水溶液提取物总丹酚酸和银杏叶提取物EGb761对血管平滑肌细胞损伤的保护作用进行了比较研究。方法选用培养的10～20代大鼠血管平滑肌细胞用于实验研究。细胞用H₂O₂2(100μmol·L^-1)处理1h造成细胞氧化损伤模型，采用MTT方法观察总丹酚酸和EGb761对H₂O₂损伤细胞生存率的影响，同时以乳酸脱氢酶(LDH)、丙二醛(MDA)、一氧化氮(NO)3种物质变化作为指标，观察了总丹酚酸和EGb761对H₂O₂损伤血管平滑肌细胞的保护作用。结果总丹酚酸100，10 μg·mL^-1能显著提高细胞的存活率，而总丹酚酸1μg·mL^-1和EGb761 100，10，1μg·mL^-1对细胞的存活率没有明显的升高作用；总丹酚酸100 μg·mL^-1，EGb761 100，10，1 μg·mL^-1均能显著降低H₂O₂损伤细胞上清液中LDH 的量，总丹酚酸10，1 μg·mL^-1作用不显著；EGb761 100，10 μg·mL^-1能明显降低细胞上清中MDA的量，EGb761 1 μg·mL^-1及总丹酚酸100，10，1μg·mL^-1作用不明显；总丹酚酸100，10，1 μg·mL^-1和EGb761 100，10 μg·mL^-1明显降低H₂O₂损伤引起NO的释放。结论总丹酚酸和EGb761对H₂O₂损伤的血管平滑肌有保护作用，但作用机制似乎有所不同，需要做进一步研究。     

中药复方海康灵含药血清对过氧化氢诱导的神经细胞凋亡的影响

 目的观察海康灵对SH-SY5Y神经细胞凋亡、细胞内线粒体膜电位和钙离子的影响。方法采用血清药理学方法,用流式细胞仪观察海康灵对过氧化氢(H₂O₂)损伤的SH-SY5Y神经细胞凋亡、细胞线粒体膜电位和钙离子的影响。结果与模型组比较,海康灵含药血清能明显抑制H₂O₂引起的SH-SY5Y神经细胞的凋亡,稳定线粒体膜电位,抑制钙离子内流。结论以上结果提示,海康灵可通过抑制胞浆钙离子升高,进而稳定线粒体膜电位,从而发挥其抑制神经细胞凋亡的作用。     

灯盏细辛与赤芍配伍组方对H2O2致PC12细胞损伤的保护作用

目的：探讨灯盏细辛与赤芍配伍组方对H₂O₂诱导的PC12细胞氧化损伤的影响及其作用机制。方法：用H₂O₂（850 μmol·L^-1）处理PC12细胞6 h建立体外氧化应激模型,以不同质量浓度的灯盏细辛与赤芍配伍组方（6.25,12.5,25,50,100 mg·L^-1）预处理PC12细胞（3×10⁴~4×10⁴个/mL）24 h,采用MTT法检测细胞活力,比色法测定细胞培养液中乳酸脱氢酶（LDH）活性、细胞裂解液中超氧化物歧化酶（SOD）活性和丙二醛（MDA）水平,利用荧光探针DCFH-DA和罗丹明123流式细胞术分别检测细胞内活性氧（ROS）和线粒体膜电位（Δψm）。结果：与正常对照组比较,模型组的细胞存活率下降至52.78%,细胞上清液中LDH释放量上升110.13 U·L^-1,细胞内MDA和ROS水平显著增高,细胞内SOD和Δψm水平显下降（P<0.01）;与模型组比较,灯盏细辛与赤芍配伍组方可明显增加细胞存活率,降低LDH活性,降低MDA水平,抑制细胞内活性氧的生成,增加SOD活性和使线粒体膜电位升高（P<0.05,P<0.01）,且在一定范围呈剂量依赖性。结论：灯盏细辛与赤芍配伍组方对H₂O₂诱导的PC12细胞氧化损伤具有保护作用,其机制可能与其降低细胞脂质过氧化水平,提高抗氧化酶活力,抑制ROS生成和稳定线粒体膜电位有关。     

外源H2O2对不同水分条件下垂盆草线粒体稳态、生长及品质的调控作用

目的 为揭示外源H₂O₂叶面预处理对不同水分条件下垂盆草Sedum sarmentosum线粒体稳态、生长和黄酮类成分积累的调控作用。方法 设置4个处理即适宜水分、适宜水分＋1 mmol/L H₂O₂、干旱、干旱＋1 mmol/L H₂O₂处理，测定不同处理垂盆草叶肉细胞超微结构及其线粒体抗氧化系统、垂盆草生长指标、生物量、指标性成分含量及多种体外抗氧化能力。结果 在干旱胁迫条件下外源喷施1 mmol/L H₂O₂可以显著提高垂盆草线粒体超氧化物歧化酶（superoxide dismutase，SOD）、过氧化物酶（peroxidase，POD）和抗坏血酸过氧化物酶（ascorbate peroxidase，APX）活性，显著降低线粒体超氧阴离子产生速率及丙二醛（malondialdehyde，MDA）含量，减轻线粒体膜结构破坏。在干旱条件下叶片喷施H₂O₂处理的垂盆草鲜质量和干质量分别比干旱处理提高51.53%和38.78%，总黄酮、总酚含量分别提高13.37%和6.50%，但槲皮素和异鼠李素含量显著低于其他处理。适宜水分条件下喷施H₂O₂处理有利于提高生物量和异鼠李素含量。垂盆草ABTS、DPPH、OH·自由基清除能力与抗脂质过氧化能力均以适宜水分＋喷施H₂O₂处理最高，干旱＋喷施H₂O₂处理次之。结论 喷施1 mmol/L H₂O₂可以缓解干旱胁迫对垂盆草的氧化伤害，维持线粒体稳态，提高垂盆草药材产量和品质，从而协调干旱逆境下垂盆草产量和品质之间的矛盾；适宜水分条件下喷施H₂O₂亦有助于提升垂盆草产量和品质。     

青藤碱抑制H2O2诱导乳鼠心肌细胞凋亡

目的:探讨青藤碱对H₂O₂诱导乳鼠心肌细胞凋亡的影响及其可能的作用机制。方法:在原代培养的SD大鼠乳鼠心肌细胞上建立H₂O₂损伤模型,观察不同剂量青藤碱(10,30,100μmol.L^-1)对心肌细胞凋亡率、丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性、乳酸脱氢酶(LDH)活性及NF-κB蛋白表达的影响。结果:H₂O₂组与空白对照组相比,心肌细胞凋亡率显著增加(P<0.01),并随着时间的延长其凋亡率不断增高;青藤碱明显抑制H₂O₂所诱导各个时间段的心肌细胞凋亡率(P<0.01),降低MDA含量,增加SOD,LDH活性,抑制NF-κB蛋白表达。结论:青藤碱对H₂O₂诱导的乳鼠心肌细胞凋亡有抑制作用,其作用机制可能与其抗脂质氧化、抑制心肌细胞表达NF-κB有关。     

基于Nrf2/ARE信号通路探讨当归-川芎含药血清对H2O2致PC12细胞氧化损伤的保护作用

目的 研究当归-川芎含药血清（Angelicae Sinensis Radix-Chuanxiong Rhizoma medicated serum,ASRCRS）对过氧化氢（H₂O₂）诱导高分化大鼠肾上腺嗜铬瘤细胞（PC12细胞）氧化损伤的保护作用及其分子机制。方法 采用H₂O₂体外诱导PC12细胞氧化损伤,并以终体积分数为15%的ASRCRS低、中、高剂量组进行干预。采用噻唑蓝（MTT）比色法检测细胞存活率;荧光倒置显微镜观察细胞形态;试剂盒检测细胞上清液乳酸脱氢酶（LDH）,丙二醛（MDA）含量和细胞内超氧化物歧化酶（SOD）活力及活性氧（ROS）分布水平;Annexin V-FITC/PI双染法检测细胞凋亡情况;蛋白免疫印迹法（Western blot）检测核转录因子E₂相关因子2（Nrf2）,Kelch样环氧氯丙烷相关蛋白-1（Keap1）,血红素加氧酶-1（HO-1）,SOD1蛋白的表达水平。结果 选择300 μmol·L^-1 H₂O₂刺激24 h作为氧化损伤造模的条件。与正常组比较,H₂O₂模型组细胞形态异常,细胞存活率显著降低（P<0.01）;LDH,MDA含量升高（P<0.01）,SOD活力降低,ROS在细胞内分布增加;Nrf2,HO-1,SOD1蛋白表达水平均明显下调（P<0.05,P<0.01）,Keap1蛋白表达水平明显上调（P<0.01）。与模型组比较,ASRCRS不同剂量组均能改善细胞形态,提高细胞存活率,抑制细胞凋亡;显著提高SOD酶活力（P<0.01）,抑制LDH的释放（P<0.01）和ROS的生成,降低MDA含量（P<0.01）;明显上调Nrf2,HO-1,SOD1蛋白表达水平（P<0.05,P<0.01）,显著下调Keap1蛋白表达水平（P<0.01）。结论 当归-川芎含药血清可能是通过上调Nrf2的蛋白表达,激活Nrf2/抗氧化反应元件（ARE）信号通路,增强细胞抗氧化损伤能力,抑制细胞凋亡,从而发挥保护H₂O₂损伤的PC12细胞的作用。     

苓桂术甘汤含药血清通过PI3K/Akt信号通路保护H2O2诱导的H9c2细胞损伤

目的 研究苓桂术甘汤含药血清对H₂O₂诱导的H9c2细胞损伤的保护作用及与磷脂酰肌醇3-激酶/蛋白激酶B（PI3K/Akt）信号通路的关系。方法 采用血清药理学方法，制备空白血清及苓桂术甘汤含药血清。体外培养H9c2细胞，分为空白组、H₂O₂组、20%空白血清组、20%苓桂术甘汤含药血清组，给予相应药物处理12 h，再加入100 μmol·L^-1 H₂O₂继续培养6 h后进行检测。采用细胞增殖与活性检测-8（CCK-8）法检测20%苓桂术甘汤含药血清对H₂O₂诱导的H9c2细胞增殖活性的影响，荧光探针法检测线粒体活性氧（ROS）水平，比色法检测氧化应激标志物丙二醛（MDA）、乳酸脱氢酶（LDH）、过氧化氢酶（CAT）和谷胱甘肽过氧化物酶（GSH-Px）水平，蛋白免疫印迹法（Western blot）检测磷脂酰肌醇3-激酶（PI3K）、磷酸化磷脂酰肌醇3-激酶（p-PI3K）、蛋白激酶B（Akt）、磷酸化蛋白激酶B（p-Akt）的蛋白表达，实时荧光定量聚合酶链式反应（Real-time PCR）检测PI3K、Akt mRNA水平，流式细胞术检测细胞凋亡率。加入PI3K抑制剂LY294002后对线粒体ROS、LDH、GSH-Px水平，PI3K、p-PI3K、Akt、p-Akt蛋白表达及细胞凋亡率进行检测。结果 与空白组比较，H₂O₂诱导后细胞活力显著降低（P<0.01），线粒体ROS、MDA及LDH水平显著增加（P<0.01），CAT、GSH-Px水平则显著下降（P<0.01），PI3K、Akt蛋白的磷酸化及mRNA水平明显降低（P<0.05，P<0.01），细胞凋亡率显著升高（P<0.01）。与H₂O₂组比较，苓桂术甘汤含药血清能够提高H9c2细胞活力，显著降低线粒体ROS、MDA及LDH水平（P<0.01），并显著提高CAT、GSH-Px水平（P<0.01），促进PI3K、Akt的磷酸化及mRNA的表达（P<0.05，P<0.01），显著减少细胞凋亡率（P<0.01）。苓桂术甘汤含药血清与抑制剂LY294002联用后，逆转了苓桂术甘汤含药血清对H9c2细胞的上述作用（P<0.05，P<0.01）。结论 苓桂术甘汤含药血清保护H₂O₂诱导的H9c2细胞损伤可能与调控PI3K/Akt信号通路减轻氧化应激及细胞凋亡有关。     

新疆光果甘草黄酮类成分的抗氧化活性

 目的从新疆光果甘草中制备总黄酮(LGFs)及单体成分光甘草定(glabridin,GLB),并研究它们的抗氧化活性。方法用常规方法制备LGFs和GLB;利用HL-60细胞中的Myeloperoxidase/H₂O₂/HClO氧化系统和肝微粒体中的细胞色素P450/NADPH氧化系统做体外抗氧化实验模型,对LGFs和GLB的抗氧化活性进行测定。系统中自由基诱发程度由探针物DCFH-DA的氧化产物DCF的浓度来检测。银杏叶提取物EGb761用作阳性对照物。结果在两种体外模型中,LGFs和GLB均显示较强的抗氧化活性,它们清除自由基活性强度为EGb761≥GLB>LFs。结论甘草总黄酮及其中的主要活性成分GLB在HL-60细胞和肝微粒体氧化系统中具有很强的抗氧化活性。这些结果可部分解释甘草药理作用与其抗氧化预防活性的关系。     

Curculigoside attenuates human umbilical vein endothelial cell injury induced by H2O2

Aim of the study

Vessel endothelium injury caused by reactive oxygen species (ROS) including H₂O₂ plays a critical role in the pathogenesis of cardiovascular disorders. Therefore, agents or antioxidants that can inhibit production of ROS has highly clinical values in cardiovascular therapy. Curculigoside is the major bioactive compounds present in Curculigo orchioides, and possess potent antioxidant properties against oxidative stress insults through undefined mechanism(s). The present study was designed to test the hypothesis that curculigoside can inhibit H₂O₂-induced injury in human umbilical vein endothelial cells.

Materials and methods

Human umbilical vein endothelial cells (HUVECs) were treated with curculigoside in the presence/absence of hydrogen peroxide (H₂O₂). The protective effects of curculigoside OP-D against H₂O₂ were evaluated.

Results

HUVECs incubated with 400 μM H₂O₂ had significantly decreased the viability of endothelial cells, which was accompanied with apparent cells apoptosis, the activation of caspase-3 and the upregulation of p53 mRNA expression. In addition, H₂O₂ treatment induced a marked increase of MDA, LDH content and in intracellular ROS, decreased the content of nitric oxide (NO) and GSH-Px activities in endothelial cells. However, pretreatment with 0.5.5,10 μM curculigoside resulted in a significant recovery from H₂O₂-induced cell apoptosis. Also, it decreased other H₂O₂-induced damages in a concentration-dependent manner. Furthermore, pretreatment with curculigoside decreased the activity of caspase-3 and p53 mRNA expression, which was known to play a key role in H₂O₂-induced cell apoptosis.

Conclusion

The present study shows that curculigoside can protect endothelial cells against oxidative injury induced by H₂O₂, suggesting that this compound may constitute a promising intervention against cardiovascular disorders.     

银杏叶提取物对H2O2诱导的胰岛RIN-mβ细胞凋亡的影响

目的:探讨银杏叶提取物(Ginkgo biloba extract,EGb761)对过氧化氢(Hydrogen peroxide,H2O2)诱导的胰岛RIN-mβ细胞株凋亡的影响。方法:以500μmol/L H2O2作用于胰岛RIN-mβ细胞6 h建立凋亡模型;分别设空白对照组(Control)、阴性对照组(H2O2)、阳性对照组(槲皮素Que 100μmol/L)、EGb 761单用对照组(EGb 761100μmol/L),EGb 761给药组(EGb 761 10、30、100μg/ml);采用MTT检测细胞存活率,Hoechst 33258染色荧光显微镜观察细胞形态变化,PI单染色法和Annexin V-PI双染色法流式细胞术分析细胞凋亡情况。结果:与空白对照组比较,阴性对照组500μmol/L H2O2作用6 h后,细胞存活率明显降低、细胞凋亡率显著升高(P<0.01)。与阴性对照组相比,EGb 761显著降低H2O2诱导的细胞凋亡(P<0.01),且呈剂量依赖性。结论:过氧化氢可诱导胰岛RIN-mβ细胞凋亡,EGb 761对H2O2诱导的RIN-mβ细胞损伤和凋亡具有明显的保护作用。     

Eucommia ulmoides Oliv. Bark. protects against hydrogen peroxide-induced neuronal cell death in SH-SY5Y cells

Ethnopharmacological relevance

Eucommia ulmoides Oliv. Bark. (EUE), has commonly been used to fortify the muscles and lungs, lower blood pressure, prevent miscarriage, improve the tone of liver and kidneys, and promote longevity the traditional tonic medicines of Korea, China, and Japan.

Aim of the study

In this study, we investigated that the neuroprotective activities and possible mechanisms of EUE aqueous extract in hydrogen peroxide (H₂O₂)-induced neuronal cell death in human SH-SY5Y neuroblastoma cells.

Material and method

We examined the effects of EUE against H₂O₂-induced cytotoxicity, DNA condensation, the production of reactive oxygen species (ROS), loss of mitochondria membrane potential (MMP), the proteolysis of cleaved poly-ADP-ribose polymerase (PARP), and the expression of Bcl-2, Bcl-xL, cleaved caspase-3, and release of cytochrome c. Moreover, we attempted to determine whether EUE suppressed the phosphorylation of c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase 1/2 (ERK 1/2), and phosphoinositide 3-kinase (PI3K)/Akt.

Results

Pretreatment with EUE increased cell viability and inhibited cytotoxicity and DNA condensation. EUE also attenuated the increase in ROS production and MMP reduction. Western blot data revealed that EUE inhibited H₂O₂-induced up- or down-regulation of cleaved PARP, cleaved caspase-3, Bcl-2, and Bcl-xL. The EUE inhibited release of cytochrome c from mitochondria to the cytosol, and significantly attenuated H₂O₂-induced phosphorylation of JNK, p38 MAPK, ERK 1/2, and PI3K/Akt.

Conclusion

The potent neuroprotective capacity of EUE, shown in these experiments, may potentially be applied in the prevention or treatment of neurodegenerative diseases such as Alzheimer's disease (AD).     

氧化苦参碱对H_2O_2诱导L02细胞损伤的抑制作用及其机制的研究

该文研究氧化苦参碱(oxymatrine,OMT)抑制H2O2诱导的L02细胞损伤的作用及其机制。以人正常肝实质细胞L02为研究对象,采用H2O2诱导氧化应激建立肝损伤模型进行实验,通过CCK-8检测OMT对L02细胞活性的影响;CSFE荧光实验检测OMT对L02细胞增殖的影响;流式细胞术检测OMT对H2O2诱导的L02细胞凋亡率的影响;DCFH-DA荧光探针检测OMT对H2O2诱导的L02细胞内ROS含量;微板比色法检测OMT对GSH-PX和SOD活性的影响。结果显示,OMT在6.25~100 mg·L-1通过诱导NADPH的产生,增强L02细胞内GSH-PX酶和SOD酶的活性,进而促进GSH介导的活性氧ROS的清除,从而抑制H2O2诱导的L02细胞凋亡的发生,达到抑制H2O2诱导L02细胞损伤的作用。     

Suppression of experimental abdominal aortic aneurysms in the mice by treatment with Ginkgo biloba extract (EGb 761)

Ethnopharmacological relevance

Ginkgo biloba extract (EGb 761) is widely used to treat cerebral disorders. Clinical trials have demonstrated therapeutic benefits of EGb 761 in various vascular diseases. Because the potential pathophysiological mechanisms appear similar to those involved in aneurysmal degeneration, we postulated that EGb 761 might affect the development and progression of experimental abdominal aortic aneurysm (AAA). This study was aimed to investigate whether EGb 761 influences the development of experimental AAAs, and to explore the underlying mechanisms.

Material and methods

C57/BL6 mice underwent abluminal application of CaCl₂ to the abdominal aorta followed by gavages with either 200 mg/kg EGb 761 per day or vehicle. Six weeks after AAA induction, aortic tissue was excised for further examinations.

Results

EGb 761 treatment reduced the aneurysm size compared with vehicle-treated controls. EGb 761 had no effect on hemodynamics or macrophage infiltration in the aortic wall. However, nuclear factor κB protein levels were decreased in the aortas of EGb 761 treated animals. The increased ROS production, SOD and CAT activities, and mRNA expression of p47phox nicotinamide adenine dinucleotide phosphate oxidase were attenuated by EGb 761 treatment. Moreover, administration of EGb 761 preserved the destruction of the wavy morphology of the elastin during AAA formation. Zymographic activity of matrix metalloproteinase (MMP)-9 and MMP-2 was lowered in EGb 761 treated mice.

Conclusions

These results suggest that treatment with EGb 761 in mice prevented the development of CaCl₂-induced AAA. The possible mechanisms include decreased oxidative damage and inflammation, preservation of aortic wall architecture, and altered MMPs activities.     

Neuroprotective effect of modified Wu-Zi-Yan-Zong granule,a traditional Chinese herbal medicine,on CoCl2-induced PC12 cells

Aim of the study

To investigate the neuroprotective effect of aqueous extract of modified Wu-Zi-Yan-Zong granule (MWG), a traditional Chinese herbal medicine, against CoCl₂-induced neurotoxicity in PC12 cells.

Materials and methods

Cell viability assay, apoptosis rate assay, ROS detection and mitochondrial membrane potential (MMP) assay were performed. In addition, cytochrome c, caspase-3, PARP and MAPKs were also detected by Western blotting.

Results

MWG extract increased viability and suppresses early and middle/late stage apoptosis in a dose-dependent manner in CoCl₂-induced PC12 cells. Moreover, MWG extract decreased the level of intracellular reactive oxygen species (ROS), increased MMP, regulated Bcl-2 family protein expression (Bcl-2 and Bcl-XL) and inhibited the release of cytochrome c from the mitochondria. In addition, MWG extract attenuated activation of caspase-3 and poly ADP-ribose polymerase (PARP) and inhibited the phosphorylation of ERK, c-Jun NH₂-terminal kinase (JNK) and p38 MAPKs.

Conclusions

MWG extract exhibited significant neuroprotective effect on PC12 cells, and this effect may be associated with the suppression of ROS generation and inhibition of mitochondria-mediated caspase and MAPK signaling pathways.     

Effects of taraxasterol on iNOS and COX-2 expression in LPS-induced RAW 264.7 macrophages

Ethnopharmacological relevance

Taraxasterol was isolated from the Chinese medicinal herb Taraxacum officinale which has been frequently used as a remedy for inflammatory diseases. Our previous study has shown that taraxasterol inhibited lipopolysaccharide (LPS)-induced nitric oxide (NO) and prostaglandin E₂ (PGE₂) production in RAW 264.7 macrophages. To elucidate the underlying mechanism responsible for these effects, in the present study, we investigated the effects of taraxasterol on inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression, and mitogen-activated protein kinases (MAPKs) signaling pathway in LPS-induced RAW 264.7 macrophages.

Materials and methods

RAW 264.7 cells were pretreated with 2.5, 5 and 12.5 μg/ml of taraxasterol 1 h prior to treatment with 1 μg/ml of LPS. The mRNA expression levels of iNOS and COX-2 were examined by RT-PCR. The protein expression levels of iNOS and COX-2, and the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), p38 and c-Jun N-terminal kinase (JNK) MAPKs were measured by Western blot.

Results

The mRNA and protein expression levels of iNOS and COX-2 were inhibited by taraxasterol in a concentration-dependent manner. Further studies revealed that taraxasterol suppressed the phosphorylation of ERK1/2 and p38 in LPS-induced RAW 264.7 macrophages.

Conclusions

These results indicate that taraxasterol inhibits iNOS and COX-2 expression by blocking ERK1/2 and p38 MAPKs signaling pathway.