雷公藤红素抑制LDL及HAEC细胞氧化损伤作用

目的考察雷公藤红素(celastrol)体外对低密度脂蛋白(LDL)氧化过程及动脉血管内皮细胞氧化损伤的抑制作用。方法采用体外Cu~(2+)诱导LDL氧化修饰的体外化学反应模型,设置阴性对照、模型对照及雷公藤各剂量组,测定Cu~(2+)诱导氧化LDL的动力学曲线,分析比较各实验组的曲线下面积(AUC)、延滞期持续时间(lag time)及脂质过氧化物产生量(TBARS值);MTT法测定细胞活性,以确定雷公藤红素对正常细胞的安全剂量;建立AAPH诱导的人主动脉内皮细胞HAEC氧化损伤的细胞模型,设置阴性对照、模型对照及雷公藤各剂量组,测定细胞的乳酸脱氢酶(LDH)漏出量、超氧化物岐化酶(SOD)及谷胱甘肽过氧化物酶(GPX)活性,Hoechst 33258荧光染色观察细胞核受损伤情况,RTq PCR法分析Nrf2、HO-1 mRNA表达水平。结果体外实验结果显示,celastrol在体外较低的剂量条件下(100 nmol·L~(-1)~1μmol·L~(-1))即能有效延长LDL氧化过程中的迟滞期,降低反应动力学曲线的AUC以及脂质过氧化物的生成,表明celastrol在体外能有效抑制Cu~(2+)诱导的LDL氧化。细胞实验结果显示,在100~400 nmol·L~(-1)剂量范围内,celastrol能有效降低AAPH所致HAEC细胞的LDH漏出量,维护细胞膜和细胞核的完整性;提高受损细胞的Nrf2和HO-1mRNA表达,提高受损细胞的SOD、GPX酶活,从而提升内皮细胞的抵抗氧化应激的能力。结论 celastrol可在体外有效抑制Cu~(2+)诱导人LDL氧化损伤,在无细胞毒安全剂量下(100~400 nmol·L~(-1))可抑制AAPH所致的HAEC细胞氧化应激损伤。     

抗氧化：防治动脉粥样硬化的新途径

动脉粥样硬化(atherosclerosis,AS)是一类严重威胁人类健康的疾病,是心脑血管疾病的重要病理基础,因而抗AS药的研究日益受到重视.AS传统的治疗措施多为对危险因素(高脂血症,高血压等)的治疗.近年来AS发生的氧化修饰脂蛋白学说日益受到重视.氧化修饰低密度脂蛋白(oxidizedmodified low density lipoprotein,OX-LDL)在AS中具有重要作用,因此,防止LDL氧化的药物成为近年研究抗AS的新途径.我们就近年来抗氧化剂对AS发生发展过程的影响作一阐述.1 AS发生的氧化修饰脂蛋白学说AS主要以内皮细胞损伤、血管平滑肌细胞增殖及内膜下移为特点.内皮细胞损伤为AS发生的始动环节.造成内皮细胞损伤的因素很多,其中高胆固醇血症仍被认为是最重要的危险因素之一.现已证实胆固醇的致AS效应主要在于胆固醇中的LDL,特别是OX-LDL.OX-LDL是由天然LDL(n-LDL)经过氧化修饰形成的.动脉壁中主要的3种类型细胞即内皮细胞、血管平滑肌细胞(SMC)及单核细胞都可氧化LDL.OX-LDL具有以下生物学特性:①细胞毒性作用,可使内皮细胞变性、坏死、脱落,造成内皮细胞损伤;②促进SMC增殖,OX-LDL可促进     

重组TGF_α-PE40对血管平滑肌细胞增殖的抑制作用(英文)

目的:探讨基因重组转换生长因子α-绿脓杆菌外毒素融合蛋白(TP40)对血管平滑肌细胞(SMC)增殖的抑制作用。方法:用RNA印迹法和免疫组化检测原代培养增殖期SMC及静止期SMC表皮生长因子受体(EGFR)的表达,用结晶紫染色法和[~3H]亮氨酸掺入法检测TP40对增殖期SMC和静止期SMC增殖及蛋白质合成的抑制作用,用过量EGF(TP40浓度的100倍)竞争拮抗TP40的细胞毒作用。结果:增殖期SMC EGFR的mRNA及受体蛋白质的表达显著高于静止期SMC。TP40浓度为10及100μg·L~(-1)时,对增殖期SMC增殖及蛋白质合成的抑制作用较静止期SMC强(P<0.01),对[~3H]亮氨酸掺入抑制的IC_(50)及其95％可信限分别为8.01(5.05-12.69)和121.95(90.98-163.47)μg·L~(-1)。过量EGF能完全拮抗TP40的细胞毒作用。结论:增殖期SMC能高水平地表达EGFR,TP40对增殖期SMC的增殖具有导向抑制作用,作用部位为细胞的EGFR。     

银杏叶提取物体外对铜离子诱导的人血清低密度脂蛋白氧化修饰的抑制作用(英文)

本文在体外对EGb761能否抑制钢离子诱导的人血清低密度脂蛋白氧化修饰进行了研究。低密度脂蛋白（LDL）用EGb76140,80,160mg·L(-1)‘预处理1h,然后用CuSO410μmol·(-1)氧化修饰10h。结果表明LDL被钢离子氧化修饰后低密度脂蛋白中维生素E（VE）被耗竭,丙二醛（MDA）及自身荧光物质（LF）含量升高,载脂蛋白B（apoB）的电泳迁移速率加快。EGb761剂量依赖性地抑制VE的含量降低和MDA及自身荧光物质的含量升高,载脂蛋白B的电泳迁移速率依次减慢。可见在体EGb761能抑制钢离子诱导的人血清低密度脂蛋白氧化修饰。     

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。     

前列腺素E1和E2对体外内皮细胞修饰低密度脂蛋白的作用

低密度脂蛋白(LDL)的氧化修饰是动脉粥样硬化形成(AS)的重要机制之一。细胞对LDL的修饰作用是近年来研究的热点。我们利用体外培养的免主动脉内皮细胞与LDL共同孵育,以探讨内皮细胞对LDL的氧化作用。有研究表明,大剂量前列腺素EZ(PGE2)(2～20mg/L)抑制AS,小剂量则促进AS[1];亦见有PGE1抗AS作用的报道。因此,本研究拟从抗LDL氧化修饰的角度探讨二者的抗AS机理。 材料与方法 1.家兔主动脉内皮细胞的培养　健康幼龄雌性白色家兔,体重 1.2kg,气栓处死。迅速于无菌条件下取出主动脉,洗净血迹,去除外膜及结缔组织。纵行剪开管壁,将…     

丹酚酸-A体外对人血清低密度脂蛋白氧化修饰的抑制作用

目的研究丹酚酸-A(Sal-A)对人血清低密度脂蛋白(LDL)氧化修饰的抑制作用。方法用Cu²⁺体外诱导LDL过氧化,观察Sal-A对MDA,脂褐素和维生素E含量,氧化LDL电泳迁移率以及对LDL氧化过程中自由基的产生及Sal-A螯合Cu²⁺的作用。结果LDL经Cu²⁺诱导过氧化后,丙二醛和脂褐素的生成增加,维生素E含量下降,LDL电泳迁移速度加快,LDL氧化过程中自由基的生成增加。10^-6～10^-4 mol·L^-1 Sal-A可剂量依赖性地抑制上述改变,并且Sal-A能螯合Cu²⁺。结论丹酚酸-A可有效地抑制Cu²⁺诱导的人LDL氧化,该作用可能与其清除自由基及螯合铜离子的能力有关。     

洛伐他汀对氧化修饰低密度脂蛋白刺激U937细胞缺氧诱导因子-1α表达的影响

目的：研究氧化修饰低密度脂蛋白（ox—LDL）刺激U937细胞表达缺氧诱导因子-1α（HIF-1α）的变化,并观察洛伐他汀对其的影响。方法：用油红染色的方法检测泡沫细胞的形成,采用实时定量PCR（Real—timePCR）及蛋白印记杂交技术（Westernblotting）检9n,4细胞HIF-1α表达的变化。结果：未加ox—LDL刺激的U937细胞未见泡沫细胞形成;U937细胞加入ox-LDL刺激24h后,全部转化为泡沫细胞。ox—LDL刺激下,U937细胞HIF-1α表达量显著升高,加入洛伐他汀后,HIF-1α的表达量显著降低,随剂量增加,抑制作用显著增强,有明显的剂量依赖关系。结论：ox-LDL氧化损伤导致巨噬细胞HIF—1α高表达,洛伐他汀可抑制U937细胞HIF-1α的表达,抑制泡沫细胞的形成。     

绿谷灵芝对人脐静脉内皮细胞ICAM-1和VCAM-1表达的影响

目的　采用血清药理学的方法研究绿谷灵芝含药血清对氧化型低密度脂蛋白 (ox LDL)和糖化白蛋白诱导的内皮细胞表面血管细胞粘附分子 (VCAM 1)和细胞间粘附分子 (ICAM 1)表达的影响。方法　通过细胞ELISA和流式细胞仪技术检测细胞表面VCAM 1和ICAM 1表达的变化。结果　细胞ELISA结果显示 0 2 4 g·kg-1、0 72 g·kg-1绿谷灵芝连续灌胃给药 10d后取血分离得到的血清可降低糖化白蛋白诱导的内皮细胞表面VCAM 1和ICAM 1表达 (P <0 0 5 ) ,降低ox LDL诱导的ICAM 1表达 (P <0 0 5 ) ;流式细胞技术检测结果显示 0 72 g·kg-1绿谷灵芝含药血清可降低ox LDL和糖化白蛋白诱导的内皮细胞表面ICAM 1表达(P <0 0 5 ) ,0 12 g·kg-1绿谷灵芝含药血清和无药血清对内皮细胞表面粘附分子的表达无影响。结论　绿谷灵芝含药血清可降低糖化白蛋白和ox LDL诱导的内皮细胞表面粘附分子的表达     

前胡丙素对牛主动脉平滑肌细胞增殖的抑制作用

目的:探讨前胡丙素(pra-C)对牛主动脉平滑肌细胞(SMC)增殖的影响 方法:细胞DNA的合成量由~3H-胸腺嘧啶核苷[~3H]TdR)掺入试验测定,应用流式细胞术测定细胞周期,用乳酸脱氢酶活性测定观察药物的毒性.结果:无论有无血管紧张素Ⅱ(AngⅡ),在0.01μmol/L到10μmol/L浓度范围内,pra-C均可呈浓度依赖性地抑制SMC的增殖,抑制作用主要与阻止细胞进入有丝分裂期有关,而与细胞毒性无关.结论:pra-C能够完全阻断Aug Ⅱ诱导SMC的增殖效应,部分阻止小牛血清诱导的细胞分裂,这对于血管增生性疾病的防治有重要意义.     

Pitavastatin inhibits lysophosphatidic acid-induced proliferation and monocyte chemoattractant protein-1 expression in aortic smooth muscle cells by suppressing Rac-1-mediated reactive oxygen species generation

Lysophosphatidic acid (LPA), a product generated during oxidative modification of low-density lipoprotein (LDL) and a major lipid extracted from human atherosclerotic plaques, has been shown to elicit smooth muscle cell (SMC) proliferation and inflammation, thereby being involved in atherogenesis. Recently, statins, an inhibitor of 3-hydroxy-methylglutaryl coenzyme A (HMG-CoA) reductase, have been reported to reduce the risk of cardiovascular events and slows the progression of atherosclerosis, at least partly, via pleiotropic effects. However, the effect of statin on the LPA-signaling in SMCs remains to be elucidated. In this study, we investigated whether and how pitavastatin could inhibit the LPA-induced proliferation and monocyte chemoattractant protein-1 (MCP-1) expression in cultured human aortic SMCs. LPA dose-dependently increased intracellular reactive oxygen species (ROS) generation in SMCs, which was blocked by diphenylene iodonium (DPI), an inhibitor of NADPH oxidase or pitavastatin. The anti-oxidative property of pitavastatin was prevented by simultaneous treatment of geranylgeranyl pyrophosphate. Furthermore, overexpression of dominant negative Rac-1 mutant was found to inhibit the LPA-induced ROS generation in SMCs. LPA induced Rac-1 activation in SMCs, which was suppressed by pitavastatin or LPA receptor antagonist. Pitavastatin, DPI, and an anti-oxidant N-acetylcysteine inhibited the LPA-induced proliferation and MCP-1 gene expression in SMCs. These results suggest that pitavastatin could block the LPA-induced proliferation and MCP-1 expression in SMCs by suppressing Rac-1-mediated NADPH oxidase-dependent ROS generation. Our present study provides a novel beneficial aspect of pitavastatin; pitavastatin may act as a blocker of the LPA-signaling in SMCs.     

Protection of low density lipoprotein oxidation at chemical and cellular level by the antioxidant drug dipyridamole.

1. The oxidative modification of low density lipoprotein (LDL) is thought to be an important factor in the initiation and development of atherosclerosis. Natural and synthetic antioxidants have been shown to protect LDL from oxidation and to inhibit atherosclerosis development in animals. Synthetic antioxidants are currently being tested, by they are not necessarily safe for human use. 2. We have previously reported that dipyridamole, currently used in clinical practice, is a potent scavenger of free radicals. Thus, we tested whether dipyridamole could affect LDL oxidation at chemical and cellular level. 3. Chemically induced LDL oxidation was made by Cu(II), Cu(II) plus hydrogen peroxide or peroxyl radicals generated by thermolysis of 2,2'-azo-bis(2-amidino propane). Dipyridamole, (1-10 microM), inhibited LDL oxidation as monitored by diene formation, evolution of hydroperoxides and thiobarbituric acid reactive substances, apoprotein modification and by the fluorescence of cis-parinaric acid. 4. The physiological relevance of the antioxidant activity was validated by experiments at the cellular level where dipyridamole inhibited endothelial cell-mediated LDL oxidation, their degradation by monocytes, and cytotoxicity. 5. In comparison with ascorbic acid, alpha-tocopherol and probucol, dipyridamole was the more efficient antioxidant with the following order of activity: dipyridamole > probucol > ascorbic acid > alpha-tocopherol. The present study shows that dipyridamole inhibits oxidation of LDL at pharmacologically relevant concentrations. The inhibition of LDL oxidation is unequivocally confirmed by use of three different methods of chemical oxidation, by several methods of oxidation monitoring, and the pharmacological relevance is demonstrated by the superiority of dipyridamole over the naturally occurring antioxidants, ascorbic acid and alpha-tocopherol and the synthetic antioxidant probucol.     

紫杉醇对兔血管内皮和平滑肌细胞增生影响的差异及意义

目的探讨紫杉醇对兔血管内皮和平滑肌增生影响的差异及意义.方法将兔血管平滑肌细胞接种于共培养体系上室、内皮细胞接种于下室建立体外内膜修复模型,观察紫杉醇对兔血管平滑肌和内皮细胞3H-TdR掺入、细胞计数和迁移率的影响,用直线回归法计算紫杉醇对平滑肌和内皮细胞增生迁移的半数有效抑制浓度IC50.结果在1 nmol·L-1～1 μmol·L-1之间,紫杉醇呈浓度依赖地抑制平滑肌细胞3H-TdR掺入、细胞计数和迁移(n=6, P＜0.01).在10 nmol·L-1～1 μmol·L-1之间,紫杉醇呈浓度依赖地抑制内皮细胞3H-TdR掺入、细胞计数和迁移(n=6, P＜0.01).1 nmol·L-1紫杉醇对内皮细胞3H-TdR掺入和细胞计数有抑制倾向,但与对照组相比无统计学差异.而1 nmol·L-1的紫杉醇却已显著抑制内皮细胞迁移(n=6, P＜0.01).紫杉醇对兔血管平滑肌细胞增生、迁移抑制的IC50分别为 10.09±0.47、9.16±0.54 nmol·L-1,对内皮细胞增生、迁移抑制的IC50分别为 19.05±0.35、5.37±0.51 nmol·L-1.10 nmol·L-1紫杉醇作用 20 min 在观察时间内能持续抑制融合内皮组平滑肌增生,而对数内皮组平滑肌增殖在10 d时明显高于对照组.结论紫杉醇在抑制兔血管平滑肌细胞增生的同时也抑制内皮增生,紫杉醇干预后平滑肌细胞增生延迟与内皮细胞再生延迟密切相关.     

Protective effects of Peganum harmala L. extract, harmine and harmaline against human low-density lipoprotein oxidation

Oxidative modification of low-density lipoprotein (LDL) particles has been implicated in the process of atherogenesis. Antioxidants that prevent LDL from oxidation may reduce atherosclerosis. We have investigated the protective effect of Peganum harmala-extract (P-extract) and the two major alkaloids (harmine and harmaline) from the seeds of P. harmala against CuSO4-induced LDL oxidation. Through determination of the formation of malondialdehyde (MDA) and conjugated diene as well as the lag phase, the extract (P-extract) and compounds were found to possess an inhibitory effect. Moreover, harmaline and harmine reduced the rate of vitamin E disappearance and exhibited a significant free radical scavenging capacity (DPPH*). However, harmaline had a markedly higher antioxidant capacity than harmine in scavenging or preventive capacity against free radicals as well as inhibiting the aggregation of the LDL protein moiety (apolipoprotein B) induced by oxidation. The results suggested that P. harmala compounds could be a major source of compounds that inhibit LDL oxidative modification induced by copper.     

参麦注射液对培养大鼠主动脉平滑肌细胞增殖的影响和机理研究

目的 研究参麦注射液对血管平滑肌细胞增殖的影响和机理。方法 以培养的大鼠主动脉血管平滑肌细胞为模型，通过细胞计数及测量3H-胸腺嘧啶核苷掺入量观察细胞增殖情况，同时测定培养液中超氧化物歧化酶(SOD)活性、脂质过氧化物、前列环素(PGI2)的含量，比较分析加入不同剂量参麦注射液后上述指标的变化和相互关系。结果 不同剂量参麦注射液组的平滑肌细胞增殖及3H—胸腺嘧啶核苷掺入量均显著低于对照组，SOD活性及PGI2含量显著高于对照组，脂质过氧化程度显著降低。结论 参麦注射液对血管平滑肌细胞增殖具有抑制作用，并呈剂量依赖关系，其作用可能与增加SOD活性、降低脂质过氧化物水平，升高PGI2／TXA2有关。     

Mulberry leaf extract inhibits the oxidative modification of rabbit and human low density lipoprotein

In a previous study, we demonstrated that the intake of mulberry leaves or their 1-butanol extract (MLBE) reduced the concentration of serum lipids and atheromatous thickening of arterial intima in hypercholesterolemic rabbits. In the present study, we investigated the antioxidative activity of MLBE and isoquercitrin, the main component of MLBE. First, we determined the effect on a stable radical agent, finding that quercetin, isoquercitrin and MLBE scavenged the DPPH radical. We then determined the copper-induced oxidative modification of rabbit and human low-density lipoprotein (LDL). Oxidation of LDL was spectrophotometrically monitored by changes in absorbance at 234 nm accompanied by the formation of conjugated dienes, and measured the formation of thiobarbituric acid reacting substances (TBARS). Quercetin, an aglycone of isoquercitrin, inhibited the formation of conjugated dienes and TBARS by copper-induced oxidative modification of rabbit and human LDLs. MLBE and isoquercitrin also inhibited the oxidation of LDL. These results indicate that mulberry leaves inhibit the oxidative modification of LDL and suggest that mulberry leaves may had prevent atherosclerosis.     

Fluvastatin reduces modification of low-density lipoprotein in hyperlipidemic rabbit loaded with oxidative stress

The in vivo antioxidant effect of fluvastain, a 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, was investigated using Watanabe heritable hyperlipidemic (WHHL) rabbits subjected to nicotine-free cigarette smoke extracts as oxidative stress. Fluvastatin was given orally at doses of 10 and 30 mg/kg per day for 5 months. The cigarette smoke extracts were prepared by bubbling the gas phase of smoke into phosphate-buffered saline and was injected daily into the rabbit ear vein. The rabbits chronically treated with the cigarette smoke extracts showed an increase in plasma lipid peroxide levels, estimated as thiobarbituric acid-reactive substances. Oxidative modification of plasma low-density lipoprotein (LDL) was assessed by anion-exchange high-performance liquid chromatographic analysis, LDL susceptibility to oxidation, LDL incorporation into macrophages and thiobarbituric acid-reactive substances levels in LDL. Treatment with fluvastatin significantly reduced these effects induced by the cigarette smoke extracts in a dose-related manner and exerted a cholesterol-lowering effect. At the end of the experiment, the cigarette smoke extracts caused accumulation of cholesteryl ester in the thoracic aorta, while fluvastatin significantly prevented this accumulation. These results indicate that fluvastatin can exert an antioxidant effect in vivo, with a strong effect on oxidative stress such as smoking, a major risk factor of atherosclerosis.     

The inhibition of the oxidation of low density lipoprotein by (+)-catechin, a naturally occurring flavonoid.

(+)-Catechin inhibited the copper-catalysed oxidation of human low density lipoprotein (LDL) in a dose-dependent manner with complete inhibition at 20 micrograms/mL. The flavonoid at a concentration of 50 micrograms/mL also inhibited oxidation of LDL induced by the mouse transformed macrophage J774, human monocyte-derived macrophages and vascular endothelial cells isolated from human umbilical cords. LDL modified by copper-catalysed or cell-induced oxidation was endocytosed and degraded by human macrophages at a much greater rate than native LDL. LDL reisolated from copper or cell incubations in the presence of (+)-catechin was endocytosed and degraded at rates similar to native LDL. (+)-Catechin appeared to inhibit the uptake and degradation by macrophages of cell-modified LDL. The actions of (+)-catechin on cell-induced oxidation of LDL are consistent with the ability of flavonoids of similar structure to inhibit lipoxygenases and with a role for lipoxygenases in cell-induced modification of LDL in vivo.     

Hibiscus anthocyanins-rich extract inhibited LDL oxidation and oxLDL-mediated macrophages apoptosis.

The oxidative modification of low-density lipoprotein (LDL) plays a key role in the pathogenesis of atherosclerosis. Anti-oxidative reagents, which can effectively inhibit LDL oxidation, may prevent atherosclerosis via reducing early atherogenesis, and slowing down the progression to advance stages. As shown in previous studies Hibiscus sabdariffa L. is a natural plant containing a lot of pigments that was found to possess anti-oxidative of activity. Therefore, in this study, we evaluated the anti-oxidative activity of Hibiscus anthocyanins (HAs) by measuring their effects on LDL oxidation (in cell-free system) and anti-apoptotic abilities (in RAW264.7 cells). HAs have been tested in vitro examining their relative electrophoretic mobility (REM), Apo B fragmentation, thiobarbituric acid relative substances (TBARS) and radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity assay. The anti-oxidative activity of HAs was defined by relative electrophoretic mobility of oxLDL (decrease of 50% at 2 mg/ml), fragmentation of Apo B (inhibition of 61% at 1mg/ml), and TBARS assay (IC(50): 0.46 mg/ml) in the Cu(2+)-mediated oxidize LDL. Furthermore, the addition of >0.1 mg/ml of HAs could scavenge over 95% of free DPPH radicals, HAs showed strong potential in inhibiting LDL oxidation induced by copper. In addition, to determine whether oxLDL-induced apoptosis in macrophages is inhibited by HAs, we studied the viability, morphology and caspase-3 expression of RAW 264.7 cells. MTT assay, Leukostate staining analysis and Western blotting reveals that HAs could inhibit oxLDL-induced apoptosis. According to these findings, we suggest that HAs may be used to inhibit LDL oxidation and oxLDL-mediated macrophage apoptosis, serving as a chemopreventive agent. However, further investigations into the specificity and mechanism(s) of HAs are needed.     

Accumulation of cholesterol ester in cultured smooth muscle cells of congenital hypercholesterolemic (WHHL) rabbits treated with normal and WHHL rabbit plasma LDL

The DNA content, thymidine incorporation into DNA, and free and esterified cholesterol contents of cultured aortic smooth muscle cells (SMCs) of normal and WHHL rabbits were compared. In the first series of experiments, 5 groups of cultured normal rabbit aortic SMCs were compared: control cells and cells treated with LDL from normolipemic rabbit plasma (LDLN) and (DL from hypercholesterolemic rabbit plasma (LDLW), LDLN plus esterastin and LDLW plus esterastin. In the second series, the same groups of hereditable hypercholesterolemic WHHL rabbit aortic SMCs were compared. Results obtained with normal aortic SMCs showed that internalization of LDLW was higher than that of LDLN. LDLW was also more effective than LDLN for elevating thymidine incorporation into DNA. LDLW plus esterastin caused increases of 5, 7 and 3 times the control values in thymidine incorporation, and esterified and free cholesterol contents of the cells, respectively. In the control groups, thymidine incorporation into DNA of WHHL SMCs was 12 times more than that into the normal cells, and the free cholesterol content of WHHL cells was twice that of normal cells. Addition of LDLN caused further increases in thymidine incorporation and the esterified and free cholesterol contents of the cells. Esterastin had only a slight effect on these extremely high values. LDLW itself had no effect except that when added with esterastin it increased the cholesterol ester content of WHHL cells. The results are discussed with respect to metabolic differences between cultured aortic SMCs of normal and WHHL rabbits, and LDLs prepared from normal and hypercholesterolemic (WHHL) rabbit plasma.