大剂量前列腺素E_2与硒联用对体外培养的高脂血症兔主动脉平滑肌细胞的作用

采用离体细胞培养技术,从细胞和分子水平证实大剂量前列腺素 E_2 (56.74mol/L,20μg/ml)有抗动脉粥样硬化形成作用:抑制高脂血症性兔主动脉平滑肌细胞的增生及过氧化脂质形成,并在电镜下观察到相应变化。同时显示与抗氧化剂硒联用具明显协同作用。     

前列腺素E_2与雌二醇联合应用对动脉粥样硬化的影响和机理探讨

在本室以往研究的基础上,利用同位素技术、血清过氧化脂质(LPO)、血小板聚集性和血脂测定以及形态学和超微结构等方法,综合观察了大剂量前列腺素 E_2(PGE_2)和雌二醇联合应用对实验性动脉粥样硬化(AS)的影响,结果多种指标显示联合用药比单纯 PGE_2具有更明显的抑制 AS 的协同作用。文中根据各种检测指标的变化就其作用机理进行了讨论。     

野山杏果肉总有机酸体外抑制脂质过氧化活性研究

目的探讨野山杏果肉总有机酸(TOAWA)体外抑制脂质过氧化活性的作用。方法以维生素C为阳性对照,采用硫代巴比妥酸法,观察不同质量浓度的TOAWA对卵黄脂蛋白过不饱和脂肪酸(PUFA)过氧化体系中脂质过氧化活性以及小鼠肝脏自发性脂质过氧化及CCl4、Fe2+-维生素C和H2O2诱导的脂质过氧化活性的抑制作用。结果 TOAWA能够明显抑制PUFA过氧化体系中的脂质过氧化活性,可减轻小鼠肝脏自发性脂质过氧化及CCl4、Fe2+-维生素C和H2O2诱导的肝脏脂质过氧化程度,除了对PUFA过氧化体系中的脂质过氧化抑制作用与剂量无关外,其他抑制脂质过氧化活性均呈明显的剂量依赖性。结论野山杏总有机酸具有较强的抑制体外脂质过氧化活性的作用。     

巨噬细胞对低密度脂蛋白的修饰和PGE2抗AS作用的实验研究

目的研究巨噬细胞对低密度脂蛋白(LDL)的修饰和前列腺素E2(PGE2)对动脉粥样硬化形成的抑制作用。方法以巨噬细胞(Mp)作用LDL,并设PGE2(20mg/L)组,检测每组过氧化脂质含量,谷胱甘肽过氧化物酶活性,及形态计量学测定细胞变化和含脂量。结果细胞修饰组的脂质过氧化物含量高于给PGE2组,而谷胱甘肽过氧化物酶活性显著低于给药组。作用24小时的修饰组细胞面积明显增大,摄脂增加,均分别显著高于给药组和细胞对照组。结论提示Mp能够氧化修饰LDL并能摄取脂质,导致泡沫细胞形成。大剂量PGE2有抗LDL氧化修饰,抑制Mp细胞摄脂,和泡沫细胞形成,从而抑制动脉粥样硬化发生的作用。     

巨噬细胞对低密度脂蛋白的修饰和PGE2抗AS作用的实验研究

目的：研究巨噬细胞对低密度脂蛋白（LDL）的修饰和前列腺素E2（PGE2）对动脉粥样硬化形成的抑制作用。方法：以巨噬细胞（Mp）作用LDL,并没PGE2（20mg/L组）,检测每组过氧化脂质含量,谷胱甘肽过氧化物酶活性,及形态计量学测定细胞变化和含脂量。结果：细胞修饰组的脂质过氧化物含量高于给PGE2组,而谷胱甘肽过氧化物酶活性显著低于给药组。作用24小时的修饰组细胞面积明显增大,摄取增加,均分别显著高于给药组和细胞对照组。结论：提示Mp能够氧化修饰LDL并能摄取脂质,导致泡沫细胞形成。大剂量PGE2有抗LDL氧化修饰,抑制Mp细胞摄脂,和泡沫细胞形成,从而抑制动脉样硬化发生的作用。     

肝细胞生长因子对四氯化碳损伤原代培养大鼠肝细胞的保护作用

采用大鼠离体肝细胞原代培养24 h，并利用CCl₄造成急性肝细胞损伤模型，检定肝细胞生长因子(HGF)对肝细胞损伤的影响. 结果表明：HGF可显著降低中毒肝细胞及细胞膜脂质过氧化物水平, 抑制肝细胞脂质过氧化, 并降低谷丙转氨酶和谷草转氨酶水平, 稳定质膜；显著促进中毒肝细胞RNA和DNA的合成；超微病理证实HGF能减轻CCl₄对肝细胞质膜，染色质, 线粒体, 内质网及核蛋白体的损害.     

冠心病人过氧化脂质与前列腺素代谢关系初步探讨

本文测定了48例正常人和67例冠心病人血浆过氧化脂质、6—Keto—PGF_1α、TXB_2、血小板聚集四项指标,分析了过氧化脂质与另外三项指标的关系。结果表明:冠心病血浆过氧化脂质明显升高;过氧化脂质与6—Keto—PGF_1α呈负相关,与T/K比值、血小板聚集呈正相关。提示,冠心病高过氧化脂血症可能通过对前列腺素代谢和血小板聚集的影响参与冠心病病理生理过程。     

8-羟基喹啉酮对HepG2细胞氧化性DNA损伤的诱导作用(英文)

目的评估8-羟基喹啉酮(CuQ)对HepG2细胞的DNA损伤作用并阐明其可能的作用机制。方法 CuQ 0～4μmol.L-1处理HepG2细胞不同时间后,通过单细胞凝胶电泳实验检测细胞DNA损伤;分光光度法测定过氧化氢酶活性;苯二醛法测定细胞内谷胱甘肽(GSH)水平;硫代巴比妥酸反应物(TBARS)法检测细胞内脂质过氧化水平;Western印迹法检测NF-κB p65的变化;免疫组化方法检测细胞内8-羟基脱氧鸟苷(8-OHdG)的表达水平。结果 HepG2细胞与CuQ 0.5～4μmol.L-1作用1 h后,DNA的迁移距离明显增加(P<0.05),提示CuQ可引起DNA链断裂。CuQ能够造成细胞内GSH水平以及过氧化氢酶活性的降低。随着CuQ剂量的增加及染毒时间的延长,NF-κB由细胞浆逐渐转移至细胞核。CuQ还可以引起细胞内TBARS水平增高及8-OHdG表达水平的增强。采用GSH合成特异抑制剂DL-甲硫氨酸磺酰亚胺(BSO)预处理细胞,可明显增强CuQ对HepG2细胞DNA的损伤(P<0.05)。结论 CuQ可造成HepG2细胞氧化性DNA损伤,其作用机制与氧化应激及NF-κB p65在细胞核蓄积增高有关。     

蜂胶总黄酮镇痛作用及其机制研究

目的:研究蜂胶总黄酮(TFP)镇痛作用及其机制。方法:镇痛实验采用甲醛法、热板法、温浴法、扭体法。随机将小鼠分为生理盐水(NS)对照组、吗啡阳性对照组及不同剂量TFP组,各组灌胃给药后分别测定各实验条件下各项疼痛指标。结果:与NS对照组比较,TFP组用药后疼痛评分降低(15min后),扭体反应数减少(50、100mg/kg),舔足潜伏期延长(50、100mg/kg),缩尾反应潜伏期延长(50mg/kg),小鼠血清和脑组织中丙二醛、前列腺素-2合成及一氧化氮含量明显降低。结论:TFP具有明显的镇痛作用,其机制可能与抑制前列腺素-2和脂质过氧化及减少脑组织一氧化氮释放有关。     

肝再生刺激因子对D-氨基半乳糖所致大鼠急性肝衰竭的实验研究

参照LaBrecque等的报道,用超滤、层析技术从新鲜乳猪肝脏中提取出一种低分子量多肽类物质,具有肝再生刺激因子(HSS)的特性和作用。该因子可明显提高D-氨基半乳糖(D-GalN)所致大鼠急性肝衰竭(ALF)的存活率,经14d治疗,观察肝的组织学情况发现基本上恢复正常状态。经体内外~3H-TdR掺入DNA合成试验证明,HSS可使[~3H]掺入DNA的量明显增加,其掺入指数分别是生理盐水对照组的2.59倍和3.67倍。可明显降低肝脏脂质过氧化产物丙二醛的含量,提高肝脏还原型谷胱甘肽含量。临床资料表明:肿瘤坏死因子与重型肝炎的发病有密切关系,经葡萄球菌肠毒素B(SEB)诱生的肿瘤坏死因子(TNF-α)作用于L-929小鼠成纤维细胞的细胞毒性试验证明,HSS具有抑制TNF的活性作用。因而,HSS对急性肝衰竭的作用可能与其促进肝细胞DNA合成,提高肝枯否氏细胞吞噬功能,消除内毒素血症,抗脂质过氧化反应和抑制TNF对肝细胞的损伤有关。     

Minocycline inhibits smooth muscle cell proliferation, migration and neointima formation after arterial injury

The tetracyclines are antimicrobials that also inhibit expression of certain matrix metalloproteinases (MMPs). We conducted a series of experiments to determine if minocycline could inhibit MMP expression and limit human aortic smooth muscle cell (SMC) proliferation and migration. Analysis of SMC proliferation was performed after cells were grown in minocycline-incubated media. SMC migration activity was assayed in a micro-Boyden chamber. Western blotting revealed that minocycline reduced SMC production of MMP-2 in a dose dependent manner. Increasing doses of minocycline progressively reduced SMC proliferation to 49% of control values and limited SMC migration to 15% of control. When administered to rats with balloon injured carotid arteries, intraperitoneal doses of minocycline (70-100 mg/kg) reduced neointima formation by 76%, but were associated with liver toxicity. Higher doses were lethal and lower doses were ineffective. Minocycline, applied to injured arteries in a pluronic gel with a low pH, was also ineffective. In summary, minocycline lowers MMP-2 expression, reduces SMC proliferation and migration, and inhibits neointimal hyperplasia, but its efficacy is limited by systemic toxicity.     

Effect of heparin-like compounds on the in vitro proliferation and protein synthesis of various cell types

Previous studies have shown that heparin and heparin-like compounds inhibit the proliferation of arterial smooth muscle cells (SMC) both in vivo and in vitro. This anti-proliferative effect seems to be exerted almost exclusively on arterial SMC and related cell types. In the present study the effect of heparin (HTh) is compared with that of two sulfated glycosaminoglycans with low anticoagulant activity, sulodexide (SDX) and low molecular weight heparin (OP/LMWH) on cell proliferation and protein synthesis of 3 cell types: human arterial smooth muscle cells (SMC), fibroblast-like cells (BHK-21) and epithelial cells (rat hepatoma cells, FAO). HTh, SDX and OP/LMWH (5-100 micrograms/ml) are equally effective in reducing the proliferation of human arterial SMC. This inhibition is dose dependent and reversible. BHK-21 and FAO cells are even more sensitive than SMC to heparin-like compounds. For example 1 microgram/ml of heparin-like compounds is sufficient to produce 40-60% inhibition of FAO cell proliferation. In all types of cells HTh, SDX and OP/LMWH do not reduce the incorporation of 35S-methionine into cellular and medium proteins; they increase the radioactivity incorporated into some proteins secreted into the medium. In the case of SMC this effect is dependent on the concentration and the length of exposure to heparin-like compounds. These findings demonstrate that several cell types are sensitive to the anti-proliferative effect of heparin-like compounds.     

Correlation between oxidation of low density lipoproteins and prostacyclin synthesis in cultured smooth muscle cells

The effect of antioxidants on the oxidation of low density lipoproteins in relation to prostacyclin synthesis was investigated in the prescence of rabbit smooth muscle cells (SMC) and Fe-containing culture medium. The lipid peroxidation of low density lipoproteins (LDL) assayed as thiobarbituric acid reactive substances was increased from 0.5 to 1.4 nmol malondialdehyde/mL by the presence of smooth muscle cells. Two potent antioxidants, nordihydroguairetic acid (NDGA) and butylated hydroxytoluene (BHT), inhibited lipoprotein oxidation by IC50 values of 0.2 and 0.8 microM, respectively. Inhibition of lipoprotein oxidation was associated with an increased prostacyclin synthesis by the SMC, the effect being more pronounced with nordihydroguairetic acid than with butylated hydroxytoluene. The stable metabolite of the lipid hydroperoxide, 15-hydroxyeicosatetraenoic acid (15-HETE), formed in the 15-lipoxygenase pathway was measured following antioxidant treatment and found to be eliminated or greatly reduced by both antioxidants. The results presented show that lipid hydroperoxides, formed as a consequence of lipoprotein oxidation and promoted by the smooth muscle cells through a lipoxygenase reaction, may regulate prostacyclin synthase, a process which may be influenced by the addition of antioxidants.     

Nebivolol induces a hyperpolarizing effect on smooth muscle cells in the mouse renal artery by activation of beta-2-adrenoceptors

Nebivolol is a highly selective beta(1)-adrenoceptor antagonist with vasodilator properties involving the vascular endothelium, but its effect on the smooth muscle cells (SMC) is still unclear. In this paper, we tested the effect of nebivolol on renal artery smooth muscle cells and investigated the cellular mechanism involved. To this purpose, the denuded renal arteries isolated from mice were studied in vitro using the myograph and the nitric oxide (NO) sensor techniques, while the SMC in culture were analyzed by the patch-clamp technique. The myograph technique was used to assay the vasodilator effect of nebivolol on the arterial muscular layer, and to establish the optimal dose of the drug to be tested on single SMC by the patch-clamp technique. Using both the myograph and the patch-clamp techniques, we examined the potential contribution of beta(2)-adrenoceptors and Ca(2+)-activated K(+) channels to the nebivolol-induced effects, by exposing the denuded arteries and SMC cultures to specific inhibitors such as butoxamine (100 micromol/l), tetraethylammonium (TEA, 1 mmol/l), and iberiotoxin (100 nmol/l). The direct measurement of NO using the NO sensor enabled us to evaluate if nebivolol induces/or not the release of NO in denuded renal arteries. The results of this study show that nebivolol exerts vasodilator effects on the SMC in the denuded renal arteries and the maximal response is achieved at a concentration of 50 micromol/l. Nebivolol effects involve binding to the beta(2)-adrenoceptors and the subsequent activation of Ca(2+)-activated K(+) channels in SMC, with no contribution of NO. Taken together, the study brings new insights into the mechanism underlying the nebivolol-induced arterial vasodilation.     

Extracellular matrix-mediated control of aortic smooth muscle cell growth and migration by a combination of ascorbic acid, lysine, proline, and catechins

Extracellular matrix (ECM) function and structure are severely compromised at atherosclerotic lesion sites, contributing to initiation and progression of the disease. This study investigated whether ECM biological properties would be beneficially affected by exposure to nutrients essential for collagen synthesis and posttranslational modification. Confluent layers of human aortic smooth muscle cells (SMC) grown on collagen substrate were cultured in the presence of the tested compounds for 7 to 10 days. Pretreated cells were removed from the ECM surface by differential treatment and replaced with secondary innocent SMC cultures. Secondary SMC growth rate and invasiveness were assayed in standard growth medium. ECM protein composition was assayed immunochemically. ECM produced in the presence of ascorbic acid reduced SMC proliferation in a dose-dependent manner. Plant-derived phenolic extracts expressed different degrees of SMC growth inhibition when present during ECM production. A combination of selected nutrients had a greater effect than did individual components. The ECM deposited by SMC in the presence of ascorbate, lysine, proline, and green tea catechins inhibited SMC migration rate up to 70%. The ECM produced under conditions of chronic essential nutrient deficiency can support proatherosclerotic SMC behavior. A combination of selected nutrients can counteract these adverse effects stronger than individual components.