铅对离体大鼠肾微粒体膜流动性和膜表面负电荷密度的影响

本研究观察了的Pb~(2+)对大鼠肾微粒体膜物理状态的影响。结果表明,Pb~(2+)能明显增加ANS与膜结合后的荧光强度和荧光偏振度,但不改变荧光光谱特性。用ANS荧光滴定法研究发现,Pb~(2+)能降低膜ANS复合物的表观解离常数和增加膜上ANS的结合位点数。提示,Pb~(2+)能降低离体大鼠肾微粒体膜流动性和膜表面负电荷密度。     

四氯化碳体外与大鼠肝微粒体膜作用的研究

向大鼠肝微粒体膜悬液中加入CCl_4(0.05～1μl/ml),可致膜脂过氧化和膜脂流动性降低。二巯基苏糖醇(DTT)和普鲁卡因能拮抗上述效应。CCl_4与微粒体膜作用后,ANS荧光强度降低并出现红移。结果提示,CCl_4诱发的膜脂过氧化可致微粒体膜的物理状态发生改变。     

苯巴比妥诱导下大鼠肝微粒体药酶活性与膜流动性变化的相关性

本文用ANS和DPH为荧光探剂,研究苯巴比妥(PB)诱导下大鼠肝微粒体膜脂区流动性与膜药酶活性变化的相关性。结果表明,经PB诱导后在增加肝微粒体蛋白质含量,P-450含量及NADPH-细胞色素C还原酶等酶活性的同时,肝微粒体膜流动性明显增大,且膜深层流动性的增大与膜氨基比林N-脱甲基酶、细胞色素C还原酶活性增加有明显的直线正相关。膜胆固醇/碑脂比值明显降低。此结果提示,肝微粒体膜流动性的适当增大与PB增加单胺氧化酶系统活性之间可能存在着某种联系。     

苯巴比妥诱导下大鼠肝微粒体药酶活性与膜流动性变化的相关性

本文用ANS和DPH为荧光探剂,研究苯巴比妥(PB)诱导下大鼠肝微粒体膜脂区流动性与膜药酶活性变化的相关性。结果表明,经PB诱导后在增加肝微粒体蛋白质含量,P-450含量及NADPH-细胞色素C还原酶等酶活性的同时,肝微粒体膜流动性明显增大,且膜深层流动性的增大与膜氨基比林N-脱甲基酶、细胞色素C还原酶活性增加有明显的直线正相关。膜胆固醇/碑脂比值明显降低。此结果提示,肝微粒体膜流动性的适当增大与PB增加单胺氧化酶系统活性之间可能存在着某种联系。     

绞股蓝总皂甙对离体大鼠肝脏脂质过氧化及膜流动性损伤的保护作用

在体外实验中绞股篮总皂甙(GP)能抑制大鼠肝微粒体自发的和由Fe_-~(2+)-半胱氨酸、Vit C-NADPH和CCl_4诱发的脂质过氧化,其作用强于人参总皂甙。Fe_-~(2+)-半胱氨酸导致大鼠肝微粒体、线粒体膜流动性降低,同时加入GP可防止膜流动性的下降。     

胸腺因子D对老年大鼠肝微粒体,线粒体钙离子转运的影响

应用~(45)Ca研究了胸腺因子D(TFD)对老年大鼠肝脏亚细胞结构Ca~(2+)转运的影响,结果表明,与成年对照鼠(7月龄)相比,雄性老年大鼠(24月龄)肝微粒体,线枉体膜Ca(2+)主动摄取能力降低,肝微粒体Ca(2+)被动释放增多,给老年大鼠TFD 2 mg·kg~(-1)sc隔日一次共3月,可使其肝微枉体Ca(2+)主动摄取能力提高,Ca(2+)被动释放减少,有利于维持细胞内钙穗态,同时TFD还可逆转老年大鼠肝微粒体,线粒体膜流动性的降低及过氧化脂质的增高。     

利用ANS为探剂研究溴氰菊酯和杀灭菊酯与突触体膜的相互作用

利用ANS为荧光探剂研究了溴氰菊酯和杀灭菊酯对突触体膜表面性质的影响。这两种带α-氰基的Ⅱ亚型拟除虫菊酯杀虫剂均可进一步增强ANS-突触体膜复合物的荧光强度。双倒数作图分析表明,这一效应是由于膜上ANS 的结合量增加,而不是ANS 的荧光量子产率改变所致。通过Scatchard作图分析测知ANS-突触体膜复合物的结合常数(n,Kd),发现这两种化合物可增加突触体膜对ANS 的结合容量和亲和力,这是膜表面负电荷密度降低的结果。这一效应与溴氰菊酯和杀灭菊酯对膜脂流动性的影响是相关的。     

铅对发育中的脑脂质过氧化作用的影响

新生大鼠吸吮饮用含Pb~(2+)300 ppm和1000ppm水的母鼠乳汁(约含Pb~(2+)10～25ppm)连续21 d后,血铅和脑铅含量有显著增高,其血和脑ALAD活性亦有不同程度的抑制,说明Pb~(2+)容易由母体乳汁传递给新生大鼠引起铅中毒。另外还看到,新生大鼠脑匀浆、脑线粒体和微粒体的膜MDA含量及脂质过氧化荧光物质量比对照明显增加,血浆SOD活性抑制,均提示Pb~(2+)引起膜损伤(一是促进膜脂质过氧化作用;二是抑制SOD活性),因而出现Pb~(2+)对中枢神经系统的神经毒性。     

铅、镉对微粒体谷胱甘肽转移酶抑制机理的探讨

在纯化大鼠肝脏微粒体谷胱甘肽转移酶的基础上,我们研究了铅、镉在体外条件下,对纯化酶的影响,并初步探讨了影响机理。 结果表明,Pb~(2+)、Cd~(2+)对微粒体谷胱甘肽转移酶有明显的抑制作用,存在剂量效应、时间效应关系。按动力学方法鉴别Pb~(2+)、Cd~(2+)对纯化酶抑     

联苯双酯对人红细胞膜流动性的影响

本文用荧光探剂ANS,NPN和DPH研究联苯双酯对人红细胞膜不同层次流动性的影响。结果表明:该药可降低膜表层流动性(ANS为探剂),增加膜中层(NPN为探剂)和深层(DPH为探剂)的流动性。此外,还发现该药对由丙二醛诱发的溶血有保护作用。综合以上结果,作者对联苯双酯的药理作用进行了扼要的讨论。     

川芎嗪对兔血小板膜流动性、电泳迁移率的影响及其与抗凝作用的关系

已有报道,川芎嗪是川芎有效成分之一,对其结构已进行了鉴定。实验证明,川芎嗪有抑制血管平滑肌痉挛、改善急性心肌缺血等作用,并能抑制血小板聚集、降低血小板活性。但对于抑制聚集的机理特别是对血小板膜的作用未见报道。因此本实验研究川芎嗪对兔血小板膜流动性、电泳迁移率的影响及其与抗凝作用的关系,并初步探讨以上作用与血小板膜上生理过程的联系。     

Lipid bilayer condition abnormalities following Macrovipera lebetina obtusa snake envenomation

Viper bites is an endemic public health problem in Armenia, even in the cities. Human envenomation is often characterized by clotting disorders, hypofibrinogenemia, and local tissue necrosis. In this original study, we assess some changes of cell membranes plastic properties (namely, its microviscosity, thickness, permeability) in a rat envenomation model using the biophysical approaches. We describe the interaction of Macrovipera lebetina obtusa (MLO) venom with giant unilamellar vesicles (GUVs) composed of the native phospholipid mixtures visualized through fluorescent microscopy. GUVs with a mean diameter of 30 μm have a minimum curvature and mimic cell membranes in this respect.The membrane fluorescence probe, ANS and pyrene, were used to assess the state of membrane and specifically mark the phospholipid domains. Independent of their lipid composition, GUVs were enlarged in size as venom-dependent lipid hydrolysis proceeded. Except of the visible morphological changes, ANS and pyrene also allows us to quantify the fluidity changes in the membrane by measuring of the fluorescence intensity. The presence of viper venom in GUVs media reveals a noticeable decreasing of membrane fluidity compare the control, while the binding of fluorophores with GUVs modified by venom lead to appearance of channel activity. These studies also emphasize the importance of a membrane surface curvature for its interaction with enzymatic components of venom.     

Effects of blowing sand fine particles on plasma membrane permeability and fluidity, and intracellular calcium levels of rat alveolar macrophages

Ambient fine particulate matter (PM2.5, particulates with an aerodynamic diameter < or = 2.5 microm) can suppress alveolar macrophage (AM) functions, but the data concerning the effects of blowing sand PM2.5 on AMs remain limited. The aim of the present study is to investigate the influences of blowing sand PM2.5 on AM plasma membranes and intracellular calcium ion concentration ([Ca2+]i), and explore the mechanisms of the observed toxicological effects. The samples of normal PM2.5 (collected on sunshiny and non-blowing sand days) and blowing sand PM2.5 were collected in Wuwei city, Gansu Province, China. After AMs from rat bronchoalveolar lavage fluid (BALF) were treated in vitro for 4 h with the suspensions of these samples, the cell viability, plasma membrane permeability and fluidity, cytosolic free Ca2+ levels, and oxidative stress were examined. It was observed a dose-dependent decrease in cell viability, plasma membrane Ca2+Mg2+-dependent adenosinetriphosphatase (Ca2+Mg2+-ATPase) and Na+K+-dependent adenosinetriphosphatase (Na+K+-ATPase) activities, cellular glutathione (GSH) levels, fluorescence intensities of lipid probe 8-anilino-1-naphthalene-sulfonic acid (ANS) and fluorescence polarization of lipid probe 1,6-diphenyl-1,3,5-hexatriene (DPH) combined with cell membranes in the treatment groups of normal and blowing sand PM2.5 as compared to the control (saline group); and also observed a dose-dependent increase in the leakage of lactate dehydrogenase (LDH) and acid phosphatase (ACP), and intracellular [Ca2+]i and malondialdehyde (MDA) levels. These observations indicate blowing sand PM2.5, as similar to urban normal ones, could induce oxidative stress on AMs, enlarge plasma membrane permeability and membrane lipid fluidity, and elevate intracellular [Ca2+]i levels, resulting in cytotoxicity. A two-way ANOVA showed the toxic effects of normal and blowing sand PM2.5 on AMs were only relative to treatment dosages but not to dust types, suggesting the blowing sand PM2.5 whose airborne mass concentrations were much higher should be more harmful.     

氯化镉对大鼠肝线粒体和微粒体膜功能的影响

体外观察ＣｄＣｌ２对大鼠肝线粒体和微粒体膜流动性，膜结合酶活性，脂质过氧化产物丙二醛（ＭＤＡ）生成的影响以及维生素Ｃ的拮抗作用。结果表明，Ｃｄ２＋可在较短时间内引起膜流动性的降低和ＭＤＡ的增高，并伴有膜结合酶活性的抑制；维生素Ｃ处理不能改善膜流动性的降低。但能完全拮抗ＭＤＡ的增高，并部分缓解Ｃｄ２＋对葡萄糖－６－磷酸酶的抑制，提示Ｃｄ２＋膜毒性并非单纯由脂质过氧化所致，其中包括了对膜脂双层的直接作用。     

INTERACTION OF SOME DRUGS, METAL IONS, AND ALCOHOLS WITH RAT LIVER MICROSOMES AS STUDIED WITH A FLUORESCENT PROBE

SUMMARY 1. The effects of various compounds on the fluorescence of microsome-bound 1-anilino-8-naphthalene sulphonate (ANS) have been studied.
2. Cationic drugs and divalent metal cations enhance the fluorescence of microsome-bound ANS whereas anionic drugs and primary aliphatic alcohols decrease it.
3. No changes were observed in the fluorescence lifetime or emission maximum of ANS and it was concluded that there were no significant changes in the quantum yield of ANS fluorescence.
4. The changes in fluorescence are shown to be related to changes in ANS binding.
5. The results suggest that drug-induced changes in the binding of ANS to the microsomal membrane reflect a change in the net charge on the membrane as a result of the binding of a charged drug and that changes in ANS fluorescence cannot be directly interpreted as changes in the structure of the membrane.
6. Primary aliphatic alcohols displace ANS from the microsomal membrane but cause no change in quantum yield. It is suggested that the alcohols change the net charge on the membrane either by exposure of negative charges or occlusion of positive charges.
7. The changes in ANS fluorescence can be used as a measure of the interaction of various drugs with the microsomal membrane. Apparent binding constants determined by this method for various drugs fall in the concentration ranges over which the drugs are reported to induce changes in membrane function in various in vitro systems.     

肝移植术后患者环孢素A药物动力学与红细胞膜脂流动性的动态观察

目的探讨肝移植术后患者细胞膜脂流动性与环孢素A(CsA)药物动力学相关性,减少药物引起的不良反应.方法采用FPLA法测定CsA全血药物浓度,DPH荧光探针法测定红细胞膜脂流动性.结果红细胞膜脂流动性的动态改变与血中CsA药物浓度的变化呈负相关.结论CsA可使细胞膜脂流动性降低,长期低水平的膜脂流动性是导致肝损害的病理学基础.     

氯丁二烯吸入染毒致大鼠急性肝损害的氧化应激机理

大鼠吸入浓度为6.08 mg·L~(-1)氯丁二烯4 h后。2,12和24 h处死.染毒后2 h时血清SDH即明显升高,继而ALT升高,前者增高的幅度大于后者,肝匀浆GSH明显下降,然后升高,脂质过氧化产物MDA形成增多,肝线粒体膜脂流动性下降,与线粒体膜结合的ANS荧光增强,表明氯丁二烯所致急性肝损害可能与氧化应激机理有关。     

灯盏花乙素对超氧阴离子引起的大鼠脑突触体氧化应激的保护作用

目的：研究灯盏花乙素对超氧阴离子引起的大鼠脑突触体氧化应激的保护作用．方法：采用与黄嘌呤(0．3mmol／L)和黄嘌呤氧化酶(0．02U)体系在37℃下孵育30min,建立大鼠脑突触体超氧阴离子氧化损伤模型．通过测定脂质过氧化产物丙二醛评价脂质过氧化程度．通过脂溶性荧光探针DPH的各向异性判断突触体膜的流动性．胞内钙离子的测定采用荧光光度法,以Fura2-AM为荧光探针．测定ATP酶解释放的无机磷确定Na~ ／K~ -ATP酶的活性．结果：超氧阴离子使大鼠脑突触体的脂质过氧化产物丙二醛及胞内钙离子浓度显著上升,突触体的膜流动性和Na~ ／K~ -ATP酶的活性则显著下降,预先加入灯盏花乙素(25-100μmol／L)则能显著缓解超氧阴离子引起的氧化性损伤,表现为丙二醛的水平和胞内钙离子浓度下降,膜流动性增加及Na~ ／K~ -ATP酶活性的恢复．结论：灯盏花乙素对超氧阴离子引起的大鼠脑突触体氧化应激具有良好的保护作用．