知母皂苷BⅡ对Aβ_(25-35)诱导的原代大鼠神经细胞损伤的保护作用

目的研究甾体皂苷类化合物知母皂苷BⅡ对Aβ25-35诱导的原代大鼠神经细胞损伤的保护作用。方法体外培养原代大鼠神经细胞,采用MTT(四甲基偶氮唑盐)法检测细胞增殖活性;采用分光光度法测定细胞培养液中LDH(乳酸脱氢酶)漏出率、SOD(超氧化物歧化酶)活力、MDA(丙二醛)含量以及AChE(乙酰胆碱酯酶)活力。结果知母皂苷BⅡ10-4、10-5mol.L-1能明显增强Aβ25-35(20μmol.L-1)诱导的神经细胞增殖活性,降低LDH漏出率,并能明显提高其SOD活力、降低MDA含量,同时对AChE活力具有一定的降低作用。结论知母皂苷BⅡ能明显改善Aβ25-35诱导的原代大鼠神经细胞损伤,可能与其提高模型细胞的抗氧化能力,改善胆碱能系统相关。     

阿魏酸钠对抗Aβ25-35诱导的鼠神经元凋亡作用研究

目的 探讨阿魏酸钠对β淀粉样蛋白(Aβ25-35)通过谷氨酸诱导的鼠皮层神经元凋亡的影响.方法 培养的皮层神经元分别与谷氨酸(20μmol/L)、Aβ25-35(5μmol/L)、Aβ25-35(5μmol/L)+谷氨酸(20μmol/L)孵育,采用Hoechst 33258荧光染色法分析神经细胞凋亡;然后用谷氨酸( 50μmol/L)诱导神经元凋亡,采用荧光染色法和Westem blot观察阿魏酸钠的保护作用.结果 单独应用Aβ25-35(5μmol/L)和单独加入谷氮酸(20μmol/L)引起的皮层神经元凋亡率与对照组无明显差异;Aβ25-35与皮层神经元共同孵育5天,接着用谷氨酸处理24h,细胞凋亡率从正常的9.2%+1.5%增加到43%±8%:阿魏酸钠能够显著降低谷氨酸诱导的神经细胞凋亡百分比至21%±5%,并对抗谷氨酸引起的Bcl-2蛋白表达的降低.结论 阿魏酸钠能够减弱Aβ25-35提高谷氨酸毒性诱导的鼠皮层神经元凋亡.     

蛇毒神经生长因子对PC12细胞凋亡的保护作用

目的 建立β-淀粉样蛋白诱导大鼠嗜铬瘤PC12细胞凋亡的体外AD细胞模型,研究蛇毒神经生长因子(NGF)的保护作用.方法 以荧光显微镜观察细胞形态变化,四唑氮蓝(MTT)法,乳酸脱氢酶(LDH)释放法,流式细胞术等检测凝聚态β-淀粉样蛋白毒性片断Aβ25-35诱导的PC12凋亡,同时检测蛇毒NGF的干预作用.结果 MTT法、LDH释放率显示凝聚态Aβ25-35对PC12细胞的毒性作用呈剂量依赖,20μmol·L-1 Aβ25-35作用组细胞LDH释放率随NGF作用的浓度增高而降低;荧光显微镜观察20μmol·L-1 Aβ25-35作用于PC12细胞出现凋亡改变,NGF预处理细胞的形态明显改善;流式细胞仪分析,Aβ25-35作用PC12细胞凋亡率具有剂量依赖关系,100ng*mL-1NGF预处理的细胞凋亡率降低(P＜0.05).结论 凝聚态Aβ25-35对PC12 细胞具有毒性作用;蛇毒NGF有对抗Aβ25-35致PC12细胞凋亡的作用.     

苯氧茚酮类乙酰胆碱酯酶抑制剂YKY-7对β淀粉样蛋白诱导的神经细胞损伤的保护作用

目的观察苯氧茚酮类乙酰胆碱酯酶抑制剂YKY-7对β淀粉样蛋白25-35(β-amyloid peptide25-35,Aβ25-35)诱导的神经细胞损伤的保护作用及机制。方法以Aβ25-35诱导原代培养的大鼠皮层神经元和人神经母细胞瘤SK-N-SH细胞损伤模型,光学显微镜下观察细胞形态学以及MTT法检测YKY-7及多奈哌齐(donepezil)对损伤模型中神经细胞活率的影响,荧光显微镜、透射电镜、流式细胞仪检测YKY-7对Aβ25-35诱导的神经细胞病理性凋亡过程的影响,MTT法检测PI3K-Akt阻断剂LY294002对YKY-7神经细胞损伤保护作用的影响。结果 12.5μmol·L-1YKY-7可提高经Aβ25-35处理的大鼠皮层神经元和SK-N-SH细胞活率,且该保护作用强于相同浓度donepezil;12.5μmol·L-1YKY-7可减弱Aβ25-35诱导的SK-N-SH细胞凋亡损伤;LY294002可阻断YKY-7对Aβ25-35诱导的SK-N-SH细胞损伤的保护作用。结论苯氧茚酮类乙酰胆碱酯酶抑制剂YKY-7对Aβ25-35诱导的神经细胞凋亡具有一定的保护作用,该作用可能是通过PI3K-Akt信号通路调控。     

表没食子儿茶素促进Nrf2的核转位减轻Aβ_(25-35)对SH-SY5Y细胞的损伤

目的研究表没食子儿茶素(epigallocatechin,EGC)对Aβ_(25-35)损伤SH-SY5Y细胞的保护作用及机制。方法采用Aβ_(25-35)损伤SH-SY5Y细胞,MTT和LDH法,考察EGC对SH-SY5Y细胞活力的影响。应用DCFH-DA荧光探针检测细胞内ROS水平,通过测定细胞内SOD、GSH-Px和MDA活性,考察细胞氧化应激水平。Western blot测定细胞中Nrf2、NQO1、HO-1、Prdx6和Trx1蛋白含量。结果 Aβ_(25-35)损伤SH-SY5Y细胞,导致细胞存活率明显降低。5、10、20μmol·L~(-1) EGC能够减轻Aβ_(25-35)诱导的SH-SY5Y细胞损伤及LDH释放。而且EGC能够减少Aβ_(25-35)诱导的细胞内ROS水平的增加,减轻氧化应激损伤。同时,EGC能够明显增强Aβ_(25-35)损伤后Nrf2、NQO1、HO-1、Prdx6和Trx1的表达。结论EGC能够抑制Aβ_(25-35)诱导的SH-SY5Y细胞损伤,通过促进Nrf2核转位,提高抗氧化水平,降低Aβ_(25-35)神经毒性。     

复方脑康胶囊对β-淀粉样肽诱导SH-SY5Y细胞凋亡的保护作用研究

目的:研究复方脑康胶囊对β-淀粉样肽(Aβ)25-35(Aβ25-35)诱导人神经母细胞瘤SH-SY5Y细胞凋亡的保护作用。方法:将SH-SY5Y细胞接种后分为对照、Aβ25-35(25μmol.L-1)和复方脑康胶囊(0.725g.mL-1)+Aβ25-35(25μmol.L-1)组。通过测定细胞存活率(MTT法)、乳酸脱氢酶(LDH)漏出率、细胞轴突长度、胞体面积,观察复方脑康胶囊对Aβ导致神经毒性的保护作用。结果:与对照组比较,Aβ25-35组SY5Y细胞的轴突长度和胞体面积均较小,MTT代谢率降低,LDH漏出率升高,而加入复方脑康胶囊水提液后,可使上述指标恢复或接近正常。结论:复方脑康胶囊具有神经保护作用,可减轻Aβ导致的神经毒性。     

银杏叶聚戊烯醇对Aβ_(25-35)诱导dPC12细胞损伤的保护作用研究

目的:研究银杏叶聚戊烯醇(GP)对β淀粉样肽25-35(Aβ_(25-35))诱导dPC12细胞损伤的保护作用,为其用于阿尔茨海默病(AD)的治疗提供参考。方法:以神经生长因子(NGF)诱导PC12细胞分化为具有神经活性的dPC12细胞后,将dPC12细胞分为正常对照组(DMSO培养基)、Aβ_(25-35)处理组(DMSO培养基)和GP试验组(分别含25、50、100、200、400μg/mL GP的DMSO培养基),培养24 h后,Aβ_(25-35)处理组和GP试验组细胞均加入25μmol/L Aβ_(25-35)诱导细胞损伤(即复制AD细胞模型),24 h后采用MTT法测定细胞存活率。另取细胞分为正常对照组(DMSO培养基)、Aβ_(25-35)处理组(DMSO培养基)和GP试验组(分别含25、50、100、200μg/mL GP的DMSO培养基),同法处理后检测细胞培养液中乳酸脱氢酶(LDH)、活性氧(ROS)、丙二醛(MDA)水平。结果:与Aβ_(25-35)处理组比较,50、100、200、400μg/m L GP试验组dPC12细胞的存活率明显升高(P<0.05或P<0.01),100、200μg/mL GP试验组细胞培养液中LDH、ROS和MDA水平以及50μg/m L GP试验组细胞培养液中ROS水平均显著降低(P<0.05或P<0.01),且呈一定的浓度依赖性。结论:GP对Aβ_(25-35)致dPC12损伤有一定的保护作用,为一种潜在的AD治疗药物。     

地塞米松和淀粉样β蛋白联合作用致大鼠学习记忆能力下降

目的研究地塞米松(DEX)和淀粉样β蛋白(Aβ)联合作用对大鼠学习记忆能力的影响。方法①整体实验SD大鼠摘除肾上腺后,在sc给予DEX 0.2 mg.kg-1〔糖皮质激素(GC)维持对照组〕维持GC水平的基础上,按分组再分别sc给予DEX 1和5 mg.kg-1,Aβ25-355μg,DEX1+Aβ25-35和DEX5+Aβ25-35组,Morris水迷宫检测逃避潜伏期和游泳距离;HE染色观察海马CA1区病理变化。②体外实验海马神经元分为正常对照组,DEX 1和10μmol.L-1组,Aβ25-35 1和5μmol.L-1组(,DEX 1+Aβ25-35 1),(DEX 1+Aβ25-35 5),(DEX 10+Aβ25-35 1)和(DEX 10+Aβ25-35 5)组,MTT法检测细胞存活率,连续性监测法检测海马神经元乳酸脱氢酶(LDH)释放率;碱性单细胞凝胶电泳检测DEX 10μmol.L-1组,Aβ25-35 5μmol.L-1组,DEX 10+Aβ25-35 5和H2O2 100μmol.L-1组海马神经元拖尾长度。结果①整体实验与GC维持对照组相比,DEX 1 mg.kg-1组的逃避潜伏期和游泳距离差异无统计学意义,DEX 5 mg.kg-1和Aβ25-35组逃避潜伏期和游泳距离有升高趋势,但差异无显著性;DEX+Aβ25-35组逃避潜伏期和游泳距离显著延长(P<0.05)。与单用DEX和单用Aβ25-35组相比,DEX+Aβ25-35组海马CA1区神经元数目明显减少、排列紊乱、核固缩和浓染。②体外实验与正常对照组相比,DEX1和10μmol.L-1组及Aβ25-351μmol.L-1的细胞存活率以及LDH释放率差异无显著性,Aβ25-35 5μmol.L-1的LDH释放率升高(P<0.05);与相同浓度的单用DEX和单用Aβ25-35组相比,同时给予DEX和Aβ25-35后,细胞存活率显著降低,LDH释放率明显升高(P<0.05)。与正常对照组相比,单用DEX 10μmol.L-1组彗星拖尾长度无明显改变,单用Aβ25-35 5μmol.L-1彗星拖尾长度显著延长;与单用Aβ25-35组相比,DEX+Aβ25-35组彗星拖尾长度进一步延长(〔11.8±2.3)μm vs(9.8±1.8)μm,P<0.05〕。结论 DEX和Aβ联合作用致鼠学习记忆能力下降和海马组织损伤,此作用可能与DEX直接促进Aβ致海马神经元损伤有关。     

咖啡酸对大鼠海马神经元铝盐损伤的保护作用

目的建立氯化铝致原代培养大鼠海马神经元损伤模型,观察咖啡酸对神经元铝盐损伤的保护作用。方法新生24h内SD大鼠海马神经元原代培养,7d后用免疫组化鉴定纯度;并分成空白对照组(NaCl200μmol.L-1)、铝负荷模型组(AlCl3200μmol.L-1)、铝和不同浓度的5-LO抑制剂咖啡酸(10-6、10-7、10-8mol.L-1)混合处理组。以HE染色,MTT测定,LDH漏出率,SOD活性和MDA含量为观测指标。结果神经元纯度超过95%。铝负荷致神经细胞数目明显减少,神经元突起减少变短,原代培养海马神经元活力降低,LDH漏出明显增多,SOD活性降低,MDA含量升高。咖啡酸能剂量依赖性地减轻铝盐所致的原代培养的海马神经元损伤,提高神经细胞的活力,减少LDH漏出,明显阻遏铝负荷所致的神经元SOD活性的降低和MDA含量的升高。结论咖啡酸对铝负荷所致的原代培养大鼠海马神经元损伤有一定的保护作用,其机制可能与其抑制5-LO活性,进而抑制炎症反应和氧化应激有关。     

Aβ25-35对原代培养大鼠皮质神经元的损伤作用

目的 考察Aβ25-35对原代培养大鼠皮质神经元的损伤作用.方法 将原代培养的大鼠皮质神经元分为对照组、谷氨酸(glutamate,Glu)组及3个浓度的Aβ25-35组,每组各6孔.观察神经元的形态改变,并测定细胞存活率及培养液中乳酸脱氢酶(LDH)的活力值.结果 与对照组比较,Glu组可造成大鼠皮质神经元明显损伤,形态发生显著改变,细胞存活率为(53.1±5.5)%(P<0.01),并且培养液中LDH漏出显著增多,LDH的活力值为(39.9 4±2.9)U/g Prot (P<0.01);Aβ25-35三个剂量组神经元存活率均显著降低,分别为(69.3±5.9)%(P<0.01)、(52.7±3.0)%(P<0.01)和(33.2±1.8)%(P<0.01),Aβ25-35低、中剂量组培养液中LDH漏出未见明显改变,LDH活力值分别为(23.5±1.4)U/g Prot和(24.7±1.3)U/g Prot(P>0.05),Aβ25-35高剂量组培养液中LDH漏出显著升高,LDH活力值为(38.8±2.0)U/g Prot(P<0.01),与Glu组相当(P>0.05).结论 Aβ25-35能剂量依赖性地损伤皮质神经元,1 μmol/L Aβ25-35剂量组处理24 h后细胞存活率可降低50%左右,可用于Aβ25-35体外诱导阿尔茨海默病细胞模型的建立.     

Efficacy of gut lavage,hemodialysis, and hemoperfusion in the therapy of paraquat or diquat intoxication

Clinical and in vitro investigations were carried out to test the efficacy of gut lavage, hemodialysis, and hemoperfusion in the treatment of poisoning with paraquat or diquat. In a patient suffering from diquat intoxication 130 times more diquat was removed by gut lavage 30 h after ingestion than was removed by complete aspiration of the gastric contents.Determination of in vitro clearances for paraquat and diquat by hemodialysis showed that, at serum concentrations of 1–2 ppm, such as are frequently encountered in poisoning in man, toxicologically relevant quantities of herbicide cannot be removed from the body. At a concentration of 20 ppm, on the other hand, hemodialysis proved to be effective, the clearance being 70 ml/min at a blood flow rate of 100 ml/min. The efficacy of hemoperfusion with coated activated charcoal was on the whole better. Especially at concentrations around 1–2 ppm, the clearance values for hemoperfusion were some 5–7 times higher than those for hemodialysis.In a patient suffering from paraquat poisoning, both hemodialysis as well as hemoperfusion were carried out. The in vitro results could be confirmed: At serum concentrations of paraquat less than 1 ppm no clearance could be obtained by hemodialysis while by hemoperfusion with activated charcoal quite high clearance values were measured and the serum level dropped down to zero.

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Zusammenfassung Klinische Untersuchungen und Laboratoriumsversuche wurden durchgeführt, um die Wirksamkeit von Darmspülung, Hämodialyse und Hämoperfusion bei Paraquat- und Deiquat-Vergiftungen zu prüfen.Bei einem Patienten wurde 30 Std nach Deiquat-Aufnahme durch Darmspülung 130mal mehr Deiquat entfernt als durch vollständige Aspiration des Mageninhaltes. In vitro-Versuche ergaben, daß bei Blutserumkonzentrationen von 1–2 ppm, die bei Vergiftungen oft gemessen werden, durch Hämodialyse keine toxikologisch relevanten Paraquat- oder Deiquat-Mengen entfernt werden können. Dagegen erwies sich die Hämodialyse bei 20 ppm und einer Blutumlaufgeschwindigkeit von 100 ml/min mit einer Clearance von 70 ml/min als wirksam. Die Hämoperfusion mit beschicheter Aktivkohle war in diesen Versuchen aber eindeutig überlegen, denn insbesondere bei Konzentrationen um 1–2 ppm waren die Clearance-Werte 5–7mal höher als bei der Hämodialyse.Die in vitro-Ergebnisse wurden bei einem Patienten mit einer Paraquat-Vergiftung bestätigt: Bei Konzentrationen unter 1 ppm war die Hämodialyse wirkungslos, während durch Hämoperfusion relativ hohe Clearance-Werte erreicht wurden, so daß der Serumspiegel rasch unter die Nachweisgrenze abfiel.

     

In vitro studies on sterically stabilized liposomes (SL) as enzyme carriers in organophosphorus (OP) antagonism

This study describes a new approach for organophosphorous (OP) antidotal treatment by encapsulating an OP hydrolyzing enzyme, OPA anhydrolase (OPAA), within sterically stabilized liposomes. The recombinant OPAA enzyme was derived from Alteromonas strain JD6. It has broad substrate specificity to a wide range of OP compounds: DFP and the nerve agents, soman and sarin. Liposomes encapsulating OPAA (SL)* were made by mechanical dispersion method. Hydrolysis of DFP by (SL)* was measured by following an increase of fluoride ion concentration using a fluoride ion selective electrode. OPAA entrapped in the carrier liposomes rapidly hydrolyze DFP, with the rate of DFP hydrolysis directly proportional to the amount of (SL)* added to the solution. Liposomal carriers containing no enzyme did not hydrolyze DFP. The reaction was linear and the rate of hydrolysis was first order in the substrate. This enzyme carrier system serves as a biodegradable protective environment for the recombinant OP-metabolizing enzyme, OPAA, resulting in prolongation of enzymatic concentration in the body. These studies suggest that the protection of OP intoxication can be strikingly enhanced by adding OPAA encapsulated within (SL)* to pralidoxime and atropine.     

Steroidal sapogenin contents in some domestic plants

In order to find out the values of the steroid resources for the future use. the compositions and contents of steroidal sapogenins from 13 domestic plants have been investigated. As a result,Dioscorea nipponica, D. quinqueloba andSmilax china were found to have large amount of diosgenin. And pennogenin inTrillium kamtschaticum andParis verticillata, yuccagenin inAllium fistulosum, hecogenin inAgave americana and neochlorogenin inSolanum nigum were appeared to be major steroidal sapogenins.     

Synthesis,Cytotoxicity and Antileishmanial Activity of Some N-(2-(indol-3-yl)ethyl)-7-chloroquinolin-4-amines

We report herein the condensation of 4,7-dichloroquinoline (1) with tryptamine (2) and D-tryptophan methyl ester (3) . Hydrolysis of the methyl ester adduct (5) yielded the free acid (6) . The compounds were evaluated in vitro for activity against four different species of Leishmania promastigote forms and for cytotoxic activity against Kb and Vero cells. Compound (5) showed good activity against the Leishmania species tested, while all three compounds displayed moderate activity in both Kb and Vero cells.     

Aquatic Insects and Trace Metals: Bioavailability,Bioaccumulation, and Toxicity

Abstract

The uptake of metals from food and water sources by insects is thought to be additive. For a given metal, the proportions taken up from water and food will depend both on the bioavailable concentration of the metal associated with each source and the mechanism and rate by which the metal enters the insect. Attempts to correlate insect trace metal concentrations with the trophic level of insects should be made with a knowledge of the feeding relationships of the individual taxa concerned. Pathways for the uptake of essential metals, such as copper and zinc, exist at the cellular level, and other nonessential metals, such as cadmium, also appear to enter via these routes. Within cells, trace metals can be bound to proteins or stored in granules. The internal distribution of metals among body tissues is very heterogeneous, and distribution patterns tend to be both metal and taxon specific. Trace metals associated with insects can be both bound on the surface of their chitinous exoskeleton and incorporated into body tissues. The quantities of trace meals accumulated by an individual reflect the net balance between the rate of metal influx from both dissolved and particulate sources and the rate of metal efflux from the organism. The toxicity of metals has been demonstrated at all levels of biological organization: cell, tissue, individual, population, and community. Much of the literature pertaining to the toxic effects of metals on aquatic insects is based on laboratory observations and, as such, it is difficult to extrapolate the data to insects in nature. The few experimental studies in nature suggest that trace metal contaminants can affect both the distribution and the abundance of aquatic insects. Insects have a largely unexploited potential as biomonitors of metal contamination in nature. A better understanding of the physico-chemical and biological mechanisms mediating trace metal bioavailability and exchange will facilitate the development of general predictive models relating trace metal concentrations in insects to those in their environment. Such models will facilitate the use of insects as contaminant biomonitors.