甘氨酰谷氨酰胺对缺氧/复氧损伤心肌细胞的保护作用及机制研究

目的观察甘氨酰谷氨酰胺(Gly-Gln)对缺氧/复氧(H/R)损伤后心肌细胞凋亡、线粒体膜电位及心肌酶释放的影响,探讨Gly-Gln对心肌H/R损伤的防治作用及机制。方法利用原代培养的SD大鼠乳鼠心肌细胞建立体外心肌H/R模型,实验分为Control组,H/R组,H/R+Gly-Gln(1,4,16 mmol·L-1)组,Gly-Gln(1,4,16 mmol·L-1)组。采用MTT法测定各组心肌细胞存活率;并检测各组培养液中乳酸脱氢酶(LDH)、肌酸激酶(CK)含量;以Annexin V联合PI染色法检测各组心肌细胞凋亡率;以JC-1为荧光分子探针检测各组心肌细胞线粒体膜电位(△Ψm)变化。结果 H/R组心肌细胞活力低于对照组(P<0.01),而培养液中心肌细胞释出的LDH、CK含量则高于对照组(P<0.01);H/R+Gly-Gln组心肌细胞活力高于H/R组(P<0.01),而培养液中LDH、CK含量则低于H/R组(P<0.05),其效应在一定浓度范围内呈剂量依赖关系。H/R组心肌细胞凋亡率升高,线粒体膜电位明显低于对照组(P<0.01);H/R+Gly-Gln组心肌细胞凋亡率较H/R组降低(P<0.05),且心肌细胞线粒体膜电位升高,与H/R组比较差异有显著性(P<0.01)。结论 Gly-Gln可对抗H/R损伤,发挥细胞保护作用,维持心肌细胞活力,减少心肌细胞H/R损伤所致心肌酶(LDH、CK)释放,并可抑制心肌细胞凋亡,具体机制可能与其稳定心肌细胞线粒体膜电位等有关。     

甘西鼠尾草对缺氧/复氧H9c2大鼠心肌细胞的保护作用

目的探究甘西鼠尾草对培养H9c2大鼠心肌细胞缺氧/复氧损伤的保护作用及机制。方法采用体外细胞培养方法培养乳鼠心肌细胞,建立缺氧/复氧损伤心肌细胞模型,用甘西鼠尾草进行细胞给药,干预细胞生长过程。将培养的H9c2大鼠心肌细胞随机分为6组,分别为缺氧/复氧模型组(hypoxia/reoxygenation,H/R组);正常对照组(control,C组);缺氧/复氧模型+维拉帕米(verapamil)阳性对照组(H/R+V组);缺氧/复氧模型+甘西鼠尾草低、中和高剂量(0.01、0.1和1.0mg·L~(-1))干预组(H/R+L、M、H组)。使用噻唑蓝(thiazolyl blue tetrazolium,MTT)法测定细胞存活率;收集所培养的细胞上清液测定丙二醛(malondialdehyde,MDA)的含量和乳酸脱氢酶(lactate dehydrogenase,LDH)的活性;使用荧光酶标仪,测定能够反映细胞内活性氧(reactive oxygen species,ROS)水平高低的荧光吸光度值。结果甘西鼠尾草可明显提高心肌细胞存活率,有效减少细胞内LDH漏出量和胞浆内MDA的含量,并降低细胞内ROS水平。结论甘西鼠尾草对缺氧/复氧损伤心肌细胞具有显著的保护作用,其作用机制可能与其增强细胞清除氧自由基能力、减少脂质过氧化物的产生有关。     

白藜芦醇通过调控自噬减轻乳大鼠心肌细胞低氧复氧损伤

目的探讨白藜芦醇(Res)对低氧复氧(H/R)损伤心肌细胞的保护作用。方法采用三气培养箱法制备乳大鼠心肌细胞H/R损伤模型(H12 h/R12 h)。乳大鼠心肌细胞分为5组:细胞对照组、H/R模型组、模型+Res 5和20μmol·L-1组(Res预处理细胞12 h,然后H12 h/R12 h)和模型+Res 20μmol·L-1+氯喹(CQ)10μmol·L-1组(Res预处理细胞12 h,然后含CQ的培养基H12 h/R12 h);CCK-8法检测心肌细胞存活率,比色法测定心肌细胞乳酸脱氢酶(LDH)漏出率,AnnexinⅤ/PI双染法检测细胞凋亡,免疫荧光法检测心肌细胞内微管相关蛋白1轻链3(LC3)阳性细胞率,Western印迹法检测心肌细胞Beclin 1,LC3Ⅱ和P62蛋白表达水平。结果与细胞对照组比较,H/R组心肌细胞存活率下降(P<0.01),细胞凋亡率和LDH漏出率上升(P<0.01),LC3阳性细胞率和Beclin 1表达水平无明显变化,LC3Ⅱ和P62表达水平下降(P<0.05)。与H/R组比较,Res 5和20μmol·L-1可升高心肌细胞存...     

Bcl-2介导的芹菜素抗心肌细胞缺氧/复氧损伤作用

目的探讨芹菜素(apigenin,Api)在心肌细胞缺氧/复氧损伤中的作用,并阐明Api对心肌损伤的保护作用是否主要由Bcl-2介导。方法培养H9c2心肌样细胞;随机分为正常对照(Cont)组、缺氧/复氧(Anoxia/Reoxygenation,A/R)组、Api预处理组、Api+ABT-737组。MTT法检测细胞存活率;Western blot法检测Bcl-2表达;比色法检测培养液LDH活性、细胞SOD及GSH-Px活性、MDA含量;流式细胞仪检测心肌细胞ROS含量、线粒体膜电位及细胞凋亡。结果 Api预处理25 h后,心肌细胞Bcl-2表达呈剂量依赖性上调(P<0.01);细胞存活率升高,培养液LDH活性降低,细胞SOD、GSH-Px活性升高,MDA含量与ROS生成减少,线粒体膜电位更为稳定,细胞凋亡减少(P<0.01);Bcl-2抑制剂ABT-737则可取消Api的上述心肌保护作用。结论Api抗心肌A/R损伤作用涉及Bcl-2信号通路,至少部分依赖于其对Bcl-2表达水平的上调。     

异鼠李素对H_2O_2引起的H9C2细胞氧化应激损伤的保护作用研究

目的探讨异鼠李素对氧化应激诱导的心肌细胞损伤的保护作用及其作用机制。方法用MTT实验确定异鼠李素的心肌细胞毒作用浓度,以及抗H2O2氧化应激损伤的最佳作用浓度。将实验组分为正常组、模型组、治疗组、单给药组。治疗组、单给药组均用最佳浓度的异鼠李素预孵育12h,模型组、治疗组在预孵育结束后用300μmol·L-1H2O2作用4 h,模拟心肌细胞的氧化应激损伤。利用流式细胞术检测心肌细胞凋亡细胞比例、ROS产生等指标,利用荧光显微镜检测细胞的线粒体膜电位去极化,利用荧光酶标仪检测抗氧化酶与氧化产物MDA产量,利用Western blot检测线粒体凋亡信号通路与Nrf2/ARE信号通路的相关蛋白表达。结果与正常组相比,单给药组心肌细胞的凋亡细胞比例,ROS产生,线粒体膜电位去极化,细胞质细胞色素C、caspase-9、caspase-3、Bcl-2、Bax表达,抗氧化酶与氧化产物MDA产量差异均无显著性(P>0.05);与模型组相比,治疗组心肌细胞凋亡比例明显降低(P<0.01),ROS产生明显降低(P<0.05),线粒体膜电位去极化明显改善(P<0.01),细胞质细胞色素C、caspase-9、caspase-3、Bax表达明显降低(P<0.01),Bcl-2表达增加(P<0.01),抗氧化酶表达增加(P<0.01),氧化产物MDA表达降低(P<0.01);心肌细胞中Nrf2核转位与HO-1表达均随着异鼠李素预孵育时间的延长而增加。结论异鼠李素能够保护H2O2引起的心肌细胞损伤。其机制为影响线粒体凋亡通路以及激活Nrf2/ARE信号通路,实现抗氧化、抗凋亡功能。     

淫羊藿苷对高糖诱导H9c2心肌细胞凋亡的抑制作用

目的 研究淫羊藿苷(ICA)对高糖诱导大鼠心肌细胞H9c2凋亡的抑制作用及其机制。方法 H9c2细胞分为细胞对照组、高糖模型组、高糖+ICA 2.5,5.0,10.0,20.0和40.0μmol·L^-1组，ICA培养1 h后更换含葡萄糖33 mmol·L^-1的培养基培养3 d。CCK-8法检测H9c2细胞存活率，Annexin V-FITC/PI双染色流式细胞术检测细胞凋亡率，生物化学法测定细胞培养基葡萄糖消耗量和乳酸水平，DCFH-DA荧光探针法测定细胞内活性氧(ROS)含量，Mito-Tracker Red CMXRos荧光探针法测定线粒体膜电位，Western印迹法检测动力素相关蛋白1(DRP1)、线粒体分裂蛋白1(FIS1)、线粒体融合蛋白2(MFN2)、视神经萎缩症蛋白1(OPA1)和活化胱天蛋白酶3/6/7蛋白表达水平。结果 与细胞对照组比较，高糖模型组H9c2细胞存活率、线粒体膜电位、MFN2和OPA1蛋白表达水平显著降低(P<0.01)，细胞凋亡率、培养基葡萄糖消耗量和乳酸水平及细胞内ROS含量、DRP1、FIS1和活化...     

N-乙酰半胱氨酸对活性氧诱导的大鼠心肌细胞凋亡的作用

目的探讨N-乙酰半胱氨酸(NAC)对活性氧(ROS)介导的大鼠H9c2心肌细胞凋亡的抑制作用。方法用过氧化氢(H2O2)诱导H9c2心肌细胞,建立氧化损伤凋亡模型,并用NAC进行干预。四甲基偶氮唑蓝(MTT)法检测细胞存活率,应用流式细胞仪分析H9c2心肌细胞内ROS水平及凋亡率。结果不同剂量H2O2(0、2、4mmol/L)作用于H9c2细胞8h后,随着H2O2剂量的增高,细胞存活率降低,ROS水平及凋亡率升高(P<0.01),5mmol/L NAC有效提高了细胞存活率,明显抑制细胞内ROS水平及凋亡的发生(P<0.01)。结论 NAC通过减少自由基的产生,拮抗了ROS介导的大鼠H9c2心肌细胞凋亡。     

果糖二磷酸钠镁对心肌细胞缺氧复氧损伤修复作用的体外研究

目的:体外研究果糖二磷酸钠镁对缺氧/复氧(H/R)心肌细胞损伤的修复作用及其机制。方法:采用原代培养4d的心肌细胞建立H/R损伤模型,分为H/R组和H/R+果糖二磷酸钠镁高、中、低浓度(4.8、2.4、1.2mg·mL-1)组,另取正常细胞设为正常对照组。加入相应药物处理后分别测定各组细胞中乳酸脱氢酶(LDH)、肌酸激酶(CPK)活性及细胞内游离钙浓度([Ca2+]i),并用透射电镜观察细胞超微结构的变化。结果:与H/R组比较,果糖二磷酸钠镁组能显著降低细胞中LDH、CPK、[Ca2+]i水平(P<0.01或P<0.05),减轻细胞超微结构的损伤。结论:果糖二磷酸钠镁对H/R损伤的心肌细胞具有修复作用,其作用可能与降低钙超载有关,且具有浓度依赖性。     

黄芩茎叶总黄酮对过氧化氢诱导的心肌细胞损伤的保护作用

目的:探讨黄芩茎叶总黄酮(SSTF)对过氧化氢(H2O2)所致大鼠乳鼠心肌细胞损伤的保护作用。方法:用体外细胞培养方法,培养乳鼠心肌细胞,制备过氧化氢损伤模型,测定细胞存活率,上清液乳酸脱氢酶(LDH)的活性,细胞内丙二醛(MDA)的含量、超氧化物歧化酶(SOD)的活性,并采用原位末端标记法(TUNEL)标记细胞,测定细胞凋亡率。结果:H2O2处理心肌细胞后其存活率较正常心肌细胞下降,细胞培养液中LDH活性明显增加;其SOD活性较正常心肌细胞降低,MDA含量和心肌细胞凋亡率明显升高(均P<0.01)。SSTF(50～200mg/L)各剂量都能显著提高H2O2损伤的心肌细胞的存活率,明显抑制心肌细胞的LDH的释放,显著减少心肌细胞的MDA的含量,提高SOD的活性,明显降低心肌细胞凋亡率(均P<0.01)。结论:SSTF能减轻H2O2对心肌细胞的损伤作用,降低H2O2导致的培养心肌细胞的凋亡率。     

广西眼镜蛇毒蛋白Natrin对H_2O_2所致大鼠心肌细胞钙超载的影响

目的观察广西眼镜蛇毒蛋白Natrin对H2O2诱导的原代培养大鼠乳鼠心肌细胞内钙超载的拮抗作用。方法采取SD大鼠乳鼠心肌细胞原代培养,将心肌细胞分正常对照组:不加任何处理;钙超载模型组:检测时加入终浓度为0.3 mmol.L-1的H2O2;药物处理组:预先分别给以不同剂量的Natrin孵育24 h,检测时加入终浓度为0.3 mmol.L-1的H2O2。以Fluo-3/AM荧光指示剂负载,应用激光共聚焦显微镜技术,动态检测细胞内[Ca2+]i变化。结果动态监测15 min发现,与正常对照组比较,模型组细胞内平均荧光峰值增加49.37%,高于正常对照组(P<0.01)。而高、中、低药物浓度组平均峰荧光值比正常对照组分别增加27.52%、12.71%、5.15%。与模型组比较,药物组细胞内平均峰荧光强度值均降低(P<0.01)。结论广西眼镜蛇毒蛋白Natrin对心肌细胞钙离子通道有较好的阻断作用,能减轻H2O2诱导的心肌细胞内[Ca2+]i超载,且药物组随着药物浓度的逐渐升高,细胞内钙荧光强度逐渐下降,并呈现剂量依赖性。     

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.

---

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.     

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.     

Pharmacological treatment of COVID-19: an opinion paper

The precocity and efficacy of the vaccines developed so far against COVID-19 has been the most significant and saving advance against the pandemic. The development of vaccines has not prevented, during the whole period of the pandemic, the constant search for therapeutic medicines, both among existing drugs with different indications and in the development of new drugs. The Scientific Committee of the COVID-19 of the Illustrious College of Physicians of Madrid wanted to offer an early, simplified and critical approach to these new drugs, to new developments in immunotherapy and to what has been learned from the immune response modulators already known and which have proven effective against the virus, in order to help understand the current situation.     

Alzheimer’s disease – current trends in basic and clinical research. Highlights from the 16th ECNP

Advances in the molecular biological knowledge of neuronal nicotinic acetylcholine receptors (nAChRs) have led to a growing interest by the pharmaceutical industry in the development of novel compounds that selectively modulate nAChR function. The ability of (-)-nicotine, an activator of nAChRs, to enhance attentional aspects of cognition in animals and humans, to exert neuroprotective and anxiolytic-like effects, and presumably to mediate the negative correlation between smoking and Alzheimer's (and Parkinson's) Disease, has focused interest on the potential therapeutic utility of modulators of nAChR function for treatment of some of the deficits associated with these progressive, neurodegenerative conditions. Numerous compounds are known which activate nAChRs and which might serve as lead compounds toward the development of such agents. The pharmacologic diversity of neuronal nAChR subtypes suggests the possibility of developing selective compounds which would have more favourable side-effect profiles than existing agents. This broader class of agents, collectively called cholinergic channel modulators (ChCMs), is anticipated to encompass compounds which would have more favourable side-effect profiles than existing agents, which generally exhibit low selectivity. This selectivity may be achieved by preferentially activating some subtypes of nAChRs (i.e., Cholinergic Channel Activators, ChCAs) or inhibiting the function of other subtypes (Cholinergic Channel Inhibitors, ChCIs). An overview of the biology of nAChRs and the rationale for the use of ChCMs for the treatment of dementia related to neurodegenerative diseases are presented, followed by a discussion of lead compounds and compounds under consideration for clinical evaluation.     

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.