Effect of aldosterone receptor antagonist on cardiomyocyte apoptosis and the expression of Bcl-2,Bax protein in rats

目的 研究醛固酮受体拮抗剂螺内酯对急性心肌梗死心肌细胞凋亡及相关基因Bcl-2、Bax蛋白表达的作用.方法 通过结扎左冠状动脉前降支造成大鼠左室大面积心肌梗死模型.SD大鼠随机分为心肌梗死对照组(AMI组,0.9%氯化钠溶液2ml/d灌胃,n=24)和螺内酯治疗组(Spi组,螺内酯20 mg/kg/d,2ml灌胃,n=24),另设假手术组(Sham组,0.9%氯化钠溶液,2 ml/d灌胃,n=24).分别于术后2、7、14、21 d观察下列指标:用流式细胞学方法测定非梗死心肌细胞凋亡率及Bcl-2、Bax蛋白表达.结果 与Sham组相比较,AMI组大鼠和Spi组非梗死区心肌细胞凋亡率显著升高(P<0.01);BCL-2蛋白表达降低(P<0.05),Bax蛋白表达升高(P<0.05);与AMI组比较,大鼠心肌细胞凋亡率和非梗死区心肌细胞BCL-2蛋白表达在2 d、7 d差异无统计学意义(P>0.05),14 d、21 d有所升高(P<0.05).Bax蛋白表达在2 d、7 d差异无统计学意义(P>0.05),14 d、21 d有所降低(P<0.05).结论 螺内酯治疗可减少心肌细胞凋亡,同时增加凋亡相关基因Bcl-2蛋白的表达和减弱Bax蛋白的表达.     

脂联素对大鼠缺血/再灌注心肌细胞凋亡及相关蛋白表达的影响

目的观察脂联素(adiponectin,APN)对大鼠缺血/再灌注(ischemia/reperfusion,I/R)诱导的心肌细胞凋亡与凋亡相关蛋白Bcl-2、Bax、Caspase-3表达的影响。方法将48只大鼠随机分成假手术组(sham group)、I/R组(I/R group)、脂联素预处理组(APN+I/R group),每组16只。结扎左冠状动脉前降支,建立大鼠心肌I/R模型。各组随机选取8只,采用Evans blue-TTC双染法测定心肌梗死面积;另外8只对心功能指标进行监测,实验结束后,采用透射电镜观察心肌组织损伤;原位末端标记(TUNEL)法观察心肌细胞凋亡情况;Western blot法测定心肌Bcl-2、Bax、Caspase-3蛋白的表达。结果脂联素明显减小I/R所致的大鼠心肌梗死面积(P<0.05),改善心脏血流动力学(P<0.05),减轻透射电镜下心肌细胞形态、细胞膜、细胞核、线粒体等结构改变,减少细胞凋亡,增加Bcl-2表达(P<0.05),降低Bax与Caspase-3蛋白表达(P<0.05)。结论脂联素对I/R损伤的保护作用与抑制心肌细胞凋亡,从而减少心肌细胞损失、减轻心脏功能障碍有关,其抗凋亡作用机制可能与上调Bcl-2表达,下调Bax及Caspase-3表达有关。     

Caspase抑制剂对大鼠缺血再灌注心肌细胞凋亡及Bcl-2、Bax蛋白表达的影响

目的 探讨Caspase抑制剂z-VAD-fmk对缺血-再灌注(I-R)心肌细胞凋亡及Bcl-2、Bax蛋白表达的影响.方法 24只大鼠随机分为假手术(C)组、I-R对照(B)组和z-VAD-fmk治疗(A)组,以穿线结扎或松扎左冠状动脉制备大鼠心肌I-R模型,TUNEL法检测心肌细胞凋亡指数(AI),免疫组化法检测Bcl-2、Pax蛋白表达,并分析心肌组织病理学损害程度.结果 B组和A组Bcl-2、Bax基因蛋白表达水平均明显高于C组(P<0.05).A组凋亡指数显著低于B组;与B组比较,A组Bax蛋白表达水平有所下降,而Bcl-2蛋白表达水平显著升高(P<0.05),Bcl-2/Bax比值较对照组明显增加.结论 Caspase抑制剂可抑制I-R后心肌细胞凋亡,其机制可能与上调Bcl-2和下调Bax蛋白表达有关.     

心肌梗死大鼠非梗死区心肌细胞的凋亡及机制探讨

目的:探讨心肌梗死后不同阶段非梗死区心肌细胞凋亡的变化及其发生机制。方法:雌性Wistar大鼠,通过结扎左冠状动脉前降支制备心肌梗死模型。术后24h、1周、2周及4周随机从各组中各取10～12只大鼠,行病理组织学检查及非梗死区心肌组织的TNF-α、caspase-3、AngⅡ、凋亡细胞检测、透射电镜、Bcl-2及p53的mRNA检测。结果:大鼠梗死范围为24%～33%。术后1～4周,可见心梗组大鼠心肌组织凋亡细胞增多,凋亡细胞指数升高;AngⅡ水平逐渐升高;心肌间质可见明显TNF-α表达;p53mRNA上升,Bcl-2mRNA下降。术后2～4周,caspase-3阳性染色产物的心肌细胞数量增多。结论:(1)大鼠心梗2周后非梗死区心肌发生细胞凋亡改变。(2)局部肾素-血管紧张素-醛固酮系统(RAAS)激活、TNF-α上调及caspase-3活化可能与非梗死区细胞凋亡有关。(3)非梗死区细胞凋亡与凋亡基因p53及Bcl-2相关。     

重组腺病毒Ad-hBNP对慢性心衰大鼠心肌细胞凋亡因子及Ⅱ、Ⅲ型胶原表达的影响

目的观察外源基因人B型利钠肽对慢性心力衰竭大鼠心肌细胞凋亡因子及Ⅰ、Ⅲ型胶原表达的影响。方法 30只慢性心力衰竭模型大鼠,随机分为携带人B型利钠肽基因重组腺病毒组(Ad-hBNP组,14只)、重组空白腺病毒组(Ad-Track组,8只)、生理盐水组(NS组,8只),分别给予腹腔注射人B型利钠肽基因重组腺病毒、重组空白腺病毒及生理盐水1mL,每周1次,共4周。另设10只未造模但实行了假手术的大鼠为假手术组;4周后处死大鼠,行RT-PCR检测心肌组织Bcl-2、Bax、Caspase-3及Ⅰ、Ⅲ型胶原mRNA含量。结果 Ad-hBNP治疗后,Ad-hBNP组大鼠心肌组织Bcl-2mRNA表达较Ad-Track组及NS组升高;BaxmRNA表达较假手术组升高;Caspase-3mRNA表达较Ad-Track组、NS组及假手术组均升高。Ad-hBNP组Ⅰ、Ⅲ型胶原mRNA表达较Ad-Track组降低。结论间断给予Ad-hBNP能够影响慢性心力衰竭大鼠心肌细胞凋亡相关基因的表达,减少心肌细胞间质Ⅰ、Ⅲ型胶原的表达。     

丁苯酞对大鼠心肌缺血再灌注损伤的预防作用及机制研究

目的:研究丁苯酞对大鼠心肌缺血再灌注损伤的预防作用及机制。方法:将SD大鼠随机分为假手术组、模型组和丁苯酞低、中、高剂量组(50、75、100 mg/kg),每组10只,各组大鼠每天ig相应药物1次,假手术组及模型组大鼠ig等量生理盐水,连续3d。末次给药后除假手术组外其余各组大鼠再灌注120 min后检测各组大鼠心肌梗死面积比例、细胞凋亡率、凋亡相关蛋白[促凋亡蛋白(Caspase-3、Fas、Caspase-9)、抑制凋亡蛋白(Bcl-2)]表达、左室射血分数(LVEF)和血清中血管内皮生长因子(VEGF)含量。结果:与假手术组比较,模型组大鼠的心肌梗死面积、心肌细胞凋亡率均明显升高,心肌细胞中Caspase-3、Fas、Caspase-9蛋白表达明显增强,Bcl-2蛋白表达明显减弱,LVEF和血清VEGF含量明显降低(P<0.01)。与模型组比较,除丁苯酞低剂量组大鼠的LVEF无明显变化(P>0.05)外,其余各给药组大鼠的上述指标均明显改善(P<0.05)。与丁苯酞低剂量组比较,丁苯酞高剂量组大鼠的心肌梗死面积、细胞凋亡率均明显降低(P<0.05);丁苯酞中、高剂量组大鼠心肌细胞中Caspase-3、Fas、Caspase-9蛋白表达明显减弱,Bcl-2蛋白表达明显增强(P<0.05)。结论:丁苯酞可有效减轻大鼠心肌缺血再灌注损伤,保护心功能,其机制可能与上调VEGF有关。     

AMP579与腺苷对心肌缺血再灌注损伤的比较研究

目的比较AMP579和腺苷对大鼠心肌缺血再灌注损伤的保护作用及作用机制。方法 64只Wistar大鼠随机分为4组(每组各16只)。假手术组:开胸只穿线不结扎血管,麻醉维持150 min;缺血再灌注组(I/R):结扎冠状动脉左前降支(LAD)30 min,再灌注120 min;腺苷组:结扎LAD 30 min后,股静脉缓慢滴注腺苷305 ng·g-1·min-1,持续5 min,而后再灌注120 min;AMP579组:结扎LAD 30 min后,股静脉缓慢滴注AMP579305 ng·g-1·min-1,持续5 min,而后再灌注120 min。采用红四氮唑(TTC)法测量心肌梗死范围,TUNEL法观察各组心肌细胞凋亡数量,免疫组织化学SP法和Western blot观察Bcl-2和Bax蛋白的表达。结果与I/R组相比,腺苷组及AMP579组心肌梗死范围均明显缩小(P<0.01),心肌细胞凋亡率明显降低(P<0.01),Bax表达水平明显降低,Bcl-2表达水平明显升高(P<0.01),且AMP579组较腺苷组效果更为明显(P<0.05)。结论 AMP579和腺苷均可缩小心肌梗死范围,对缺血再灌注损伤的心肌起保护作用,且AMP579作用优于腺苷,其作用机制可能是通过上调Bcl-2蛋白的表达和下调Bax蛋白的表达,抑制再灌注心肌细胞的凋亡来实现的。     

醛固酮受体拮抗剂对心肌细胞凋亡的影响

目的研究醛固酮受体拮抗剂螺内酯对急性心肌梗死心肌细胞凋亡及相关基因Bcl-2、Bax蛋白表达的作用。方法通过结扎左冠状动脉前降支造成大鼠左室大面积心肌梗死模型。SD大鼠随机分为心肌梗死对照组(AMI组,0.9%氯化钠溶液2ml/d灌胃,n=24)和螺内酯治疗组(Spi组,螺内酯20mg/kg/d,2ml灌胃,n=24),另设假手术组(Sham组,0.9%氯化钠溶液,2ml/d灌胃,n=24)。分别于术后2、7、14、21d观察下列指标:用流式细胞学方法测定非梗死心肌细胞凋亡率及Bcl-2、Bax蛋白表达。结果与Sham组相比较,AMI组大鼠和Spi组非梗死区心肌细胞凋亡率显著升高(P<0.01);BCL-2蛋白表达降低(P<0.05),Bax蛋白表达升高(P<0.05);与AMI组比较,大鼠心肌细胞凋亡率和非梗死区心肌细胞BCL-2蛋白表达在2d、7d差异无统计学意义(P>0.05),14d、21d有所升高(P<0.05)。Bax蛋白表达在2d、7d差异无统计学意义(P>0.05),14d、21d有所降低(P<0.05)。结论螺内酯治疗可减少心肌细胞凋亡,同时增加凋亡相关基因Bcl-2蛋白的表达和减弱Bax蛋白的表达。     

中药益心康对感染CVB_3病毒的新生乳鼠体外心肌细胞凋亡及相关因子Bcl-2/Bax表达的影响

目的研究中药益心康对感染柯萨奇病毒嗜心肌毒株3型(Coxsackie virus B,CVB3)新生乳鼠体外心肌细胞凋亡及相关基因Bcl-2/Bax表达的影响,探讨中药益心康治疗病毒性心肌炎的作用机制。方法原代培养SD大鼠乳鼠体外心肌细胞,建立感染CVB3的体外心肌细胞模型,将乳鼠心肌细胞分为4组:正常组、病毒组、益心康组、利巴韦林组。采用倒置显微镜观察心肌细胞生长情况及病变程度(CPE),用RT-PCR法检测凋亡相关因子Bcl-2、Bax的表达。结果益心康组给药48 h后细胞CPE略轻于利巴韦林。益心康组Bcl-2 mRNA的相对表达量高于病毒组(P<0.01)及利巴韦林组(P<0.05),而Bax mRNA的相对表达量低于病毒对照组(P<0.01)及利巴韦林组(P<0.05),且Bcl-2/Bax高于病毒组及利巴韦林组(P<0.05)。结论中药益心康能减轻心肌损伤,保护乳鼠心肌细胞,其作用机制与下调促凋亡基因Bax、上调抑制凋亡基因Bcl-2、升高Bcl-2/Bax比值有关。     

多西环素对大鼠急性心肌梗死后转化生长因子-β1表达及心肌细胞凋亡的影响

目的：探讨多西环素对大鼠急性心肌梗死(MI)后转化生长因子-β1(TGF-β1)表达及心肌细胞凋亡的影响。方法将30只成年Wistar大鼠随机分为假手术组、MI组及多西环素组。通过结扎冠状动脉左前降支建立大鼠MI模型。采用ELISA检测血清心肌肌钙蛋白I(c-TnI)水平,Western blot检测心肌组织TGF-β1及caspase-3蛋白表达,末端标记法(TUNEL)检测心肌细胞凋亡。结果与假手术组比较,MI组及多西环素组c-TnI水平升高,TGF-β1及caspase-3蛋白表达水平升高,心肌细胞凋亡指数明显增加,差异有统计学意义(P<0.05)。多西环素可降低c-TnI水平,下调心肌组织TGF-β1及caspase-3蛋白表达,抑制心肌细胞凋亡,差异有统计学意义(P<0.05)。结论 MI后TGF-β1表达明显上调,心肌细胞凋亡增加,是心室重塑发生的重要机制。多西环素可通过下调TGF-β1表达,抑制心肌细胞凋亡,进而延缓心室重塑进程。     

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.     

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.