沙利度胺抑制异常剪切应力诱导的动脉粥样硬化形成

目的 研究沙利度胺对异常剪切应力诱导的兔颈总动脉粥样硬化病变形成的作用.方法 新西兰兔分为3组,每组13只:正常饮食组、高脂组(给予2%高胆固醇饮食)和高脂加药组(2%高胆固醇饮食+20 mg/kg沙利度胺).39只新西兰兔均予以右颈总动脉硅胶管套环,套环长度为8咖,内径为1.4mm.9周后处死动物,0周和第9周收集血清测量总胆固醇、低密度脂蛋白、高密度脂蛋白及甘油三酯等血脂指标水平.2个月后宰杀动物,取整条颈总主动脉行苏丹Ⅳ染色检测癌变面积,HE染色检测病变的病变程度.结果 0周和9周时三组动物体重差异没有显著性,一般体征无明显变化,表明动物对沙利度胺有很好耐受性.高脂组和高脂加药组总胆固醇、低密度脂蛋白、高密度脂蛋白及甘油三酯血清水平较对照组明显升高,高脂组和高脂加药组血脂指标间差异无显著性.颈总动脉苏丹Ⅳ染色结果发现,高脂组远心段和近心段有明显的红染区域示动脉粥样硬化病变形成,且近心段动脉粥样硬化病变更加明显,狭窄段基本上没有动脉粥样硬化病变形成;高脂加药组主要在近心段有少量动脉粥样硬化病变存在;正常饮食组整条颈总动脉都无可见动脉粥样硬化病变.HE染色发现,高脂组近心段有明显的动脉粥样硬化病变存在,管腔明显狭窄,动脉粥样硬化病变中有大量的脂质蓄积和细胞浸润;高脂组套环段管壁明显变薄,元明显动脉粥样硬化病变存在;高脂组远心段动脉粥样硬化病变程度较近心段轻.高脂加药组仅在近心段有内膜增生病变存在.正常饮食组内膜无明显改变.结论 剪切应力改变可以导致不同程度动脉粥样硬化病变的形成;沙利度胺对异常剪切应力诱导的兔颈总动脉粥样硬化病变的形成有抑制作用.     

异常剪切应力上调组织蛋白酶L在动脉粥样硬化斑块中表达

目的观察组织蛋白酶L(Cathepsin L)在异常剪切切应力诱导的动脉粥样硬化斑块中的表达,探讨Cathepsin L在动脉粥样硬化病变中的作用。方法采用套环法建立兔颈总动脉局部狭窄的动物模型,喂养4周;数值模拟法模拟局部狭窄远心端和近心端流场特性以及剪切应力分布;酶法测定血浆中总胆固醇、甘油三酯以及HDL水平;HE染色观察病理学改变;油红O染色观察病变处脂质的蓄积;免疫组织化学法检测Cathepsin L的表达。结果 4周后,兔血脂水平没有明显改变。套环形成局部狭窄后,颈总动脉血流流场发生显著的扰动,狭窄远心端有涡流以及二次流形成;狭窄近心端形成局部高剪切应力区域,而在远心端形成振荡的低剪切应力区域(0～0.3 Pa)。HE染色显示颈总动脉狭窄的近心端和远心端均有明显的内膜增生以及动脉粥样硬化斑块形成,近心端比远心端病变更严重。油红O染色显示有大量的脂质沉积;免疫组织化学染色结果表明病变中有大量的Cathepsin L表达,主要分布于斑块中的巨噬细胞和平滑肌细胞,并且近心端Cathepsin L的表达量明显高于远心端量,而对照侧血管仅有微量的Cathepsin L表达。结论切应力特性调节Cathepsin...     

剪切应力对家兔血管内膜增生及动脉粥样硬化斑块形成的影响

目的设计局部狭窄而导致血流动力学改变的实验模型,探讨剪切应力对血管内膜增生以及动脉粥样硬化斑块形成的影响。方法兔颈总动脉平直段套环形成狭窄度为40%的局部狭窄,饲以正常饮食4周;数值计算的方法模拟血流流场和剪切应力分布及其特征;HE染色检测颈总动脉病理改变;Verhoeff法染色观察血管弹力纤维分布;油红O染色观察斑块内的脂质沉积;高效液相色谱检测血管壁脂质含量。结果套环形成局部狭窄后,颈总动脉血流流场发生显著的扰动,狭窄远心端有涡流以及二次流形成;狭窄近心端形成局部高剪切应力区域(6Pa),而在远心端形成振荡的低剪切应力区域(0～0.3Pa);HE染色显示颈总动脉狭窄的近心端和远心端均有明显的内膜增生以及动脉粥样硬化斑块形成,近心端比远心端病变更严重,近心端增生内膜厚度为165.6±28.3μm,远心端增生内膜厚度为38.5±12.7μm,并且近心端增生内膜的细胞成分主要为圆形的泡沫细胞而远心端增生内膜的细胞成分主要为梭形平滑肌细胞;Verhoeff染色显示病变处弹力纤维排列紊乱,部分内弹力板断裂;油红O染色发现增生的斑块中有大量的脂质沉积;高效液相色谱检测也表明狭窄近心端胆固醇含量(7.6±2.1mg/g)以及远心端胆固醇含量(5.6±1.8mg/g)较对照侧(1.3±0.5mg/g)明显增加。结论高剪切应力以及低振荡剪切应力均引发动脉粥样硬化病变的形成,但不同的剪切应力对斑块的组成和特性有着不同的作用。     

低剪切应力上调基质细胞衍生因子1受体在动脉粥样硬化斑块中表达

目的观察基质细胞衍生因子1受体CXCR4在低切应力诱导的动脉粥样硬化斑块中的表达，探讨CXCR4在动脉粥样硬化病变中的作用。方法建立颈总动脉套环的局部狭窄动物模型，喂养4周；数值模拟局部狭窄远心端流场以及剪切应力分布；酶法测定血浆中总胆固醇、甘油三酯以及HDL水平；HE染色观察局部狭窄远心端病理学改变，油红O染色观察病变处脂质的蓄积，免疫荧光观察病变处CXCR4的表达。     

PKA介导的血管扩张刺激磷蛋白磷酸化对细胞迁移的影响及其调控机制

目的论证不同程度和不同形式的剪切应力的改变可以引起不同程度的动脉粥样硬化病变以及阐明体内异常剪切应力对血管壁Caveolin-1和VEGFR-2表达的调节作用。方法给予26只新西兰兔右颈总动脉硅胶管套环后雌雄均等分为2组,对照组(给予正常饮食)和高脂组(2%的高胆固醇饮食),9周后处死动物,0周和第9周收集血清测量总胆固醇、低密度脂蛋白、高密度脂蛋白和甘油三酯;采集标本,苏丹Ⅳ和HE染色观察颈总动脉动脉粥样硬化斑块面积;RT-PCR、....     

凝集素样氧化型低密度脂蛋白受体在兔颈动脉狭窄模型中的表达及血流动力的作用

目的 探讨凝集素样氧化型低密度脂蛋白受体在兔颈动脉狭窄模型中的表达及血流动力的作用.方法 健康日本大耳白兔15只,随机分为狭窄组、高脂组、对照组,每组5只.狭窄组及高脂组采用显微缝合加高脂饮食法建立实验性兔颈动脉狭窄模型,对照组给予标准饲料.共12 w.多普勒超声检测狭窄血管的血流动力学参数,采用RT-PCR检测狭窄近心端、狭窄处及狭窄远心端LOX-1表达.结果 在颈动脉狭窄处及狭窄远心端分别形成高切应力和低切应力区.高脂环境下LOX-1表达有升高趋势,LOX-1在血管狭窄处及狭窄远心端呈高表达.结论 血管狭窄后血流动力学改变影响LOX-1表达,低切应力水平促进LOX-1表达.     

Compound48/80对载脂蛋白E基因敲除小鼠颈总动脉套环诱导斑块的影响

目的采用肥大细胞脱颗粒剂———Compound 48/80作用于颈总动脉套环的载脂蛋白E基因敲除小鼠,以探讨肥大细胞脱颗粒对动脉粥样硬化斑块的影响及其可能作用机制。方法载脂蛋白E基因敲除小鼠高脂高胆固醇饲料喂养,行右颈总动脉套环术后分为实验组和对照组,分别腹腔注射Compound 48/80或D-hank’s。第4次注射后30 min,安乐死,取材。全自动生物化学分析仪测定血清中脂质含量,比色法测定血清中类胰蛋白酶活性,苏木素—伊红染色观察颈总动脉病理改变,甲苯胺蓝肥大细胞染色,免疫组织化学检测平滑肌肌动蛋白和巨噬细胞特异性抗原在斑块内的表达。结果Compound 48/80对血清脂质水平无明显影响。Compound 48/80明显刺激肥大细胞脱颗粒(80.6%±17.8%比13.5%±4.1%,P<0.01),升高血清中类胰蛋白酶活性(0.57±0.13 u/L比0.36±0.10 u/L,P<0.05)。套环能加速颈总动脉斑块形成(未套环侧颈总动脉斑块面积均为0,套环侧颈总动脉均有斑块形成),Compound 48/80增大套环侧颈总动脉斑块最大横截面积(58 500±7 500μm2比8 600±2 800μm2,P<0.01),并使管腔最大狭窄程度加重(81%±15%比41%±12%,P<0.05)。Compound 48/80使颈总动脉斑块内α平滑肌肌动蛋白表达量增加(1 219±364 iu比522±137 iu,P<0.05)和巨噬细胞特异性抗原表达量增加(426±133 iu比169±38 iu,P<0.05)。结论套环能加速载脂蛋白E基因敲除小鼠颈总动脉斑块形成。Compound 48/80使套环侧颈总动脉斑块最大横截面积和颈总动脉最大狭窄程度增加,其机制可能与其刺激肥大细胞脱颗粒促使平滑肌细胞增殖和巨噬细胞聚集有关。     

脂肪分化相关蛋白在兔动脉粥样硬化模型中的表达

研究脂肪分化相关蛋白与动脉粥样硬化发生和发展的关系。使用高胆固醇饲料喂养新西兰白兔 12周 ,复制动脉粥样硬化模型。用生物化学法测定血清总胆固醇、低密度脂蛋白胆固醇、高密度脂蛋白胆固醇、甘油三酯及动脉壁胆固醇含量 ;苏丹Ⅳ染色观察主动脉斑块面积 ;HE染色观察主动脉及肝脏的病变 ;免疫组织化学法观察脂肪分化相关蛋白在主动脉病变区及肝脏中的表达。结果发现 ,喂高胆固醇饲料的动物血清总胆固醇、低密度脂蛋白胆固醇、甘油三酯及动脉壁胆固醇含量显著升高 ,主动脉病变面积为 4 0 .1%± 7.3% ,脂肪分化相关蛋白在主动脉动脉粥样硬化病变区免疫组织化学染色呈强阳性 ,在肝脏中染色呈阴性。喂高胆固醇饲料能成功复制出兔动脉粥样硬化模型。脂肪分化相关蛋白在兔动脉粥样硬化病变中表达明显增高 ,提示脂肪分化相关蛋白与动脉粥样硬化的发生发展密切相关     

家兔颈总动脉不稳定斑块模型的建立

目的 建立家兔颈总动脉斑块模型。方法 选取60只雄性纯种的新西兰大白兔,随机分为3组,即球囊损伤+高脂组、高脂喂养组及普通饲料喂养组,每组20只。喂养12周后,分别给予中国斑点蝰蛇毒和组胺药物触发,诱发斑块破裂及血栓形成。结果 球囊损伤+高脂组存活17只白兔中,有38处病变狭窄程度超过50％,并且脂质核心较大、纤维帽的厚度小于65 μm,故判定以上38处病变为易损斑块。高脂喂养组中的19只白兔仅8处可判定为易损斑块;普通饲料喂养组中未见易损斑块。结论 高脂饮食饲养后,进行颈总动脉球囊拉伤制作兔易损斑块模型是切实可行的方法。     

烟酸对实验性动脉粥样硬化兔主动脉斑块形成和MK2表达的影响

目的探讨烟酸对动脉粥样硬化斑块形成及动脉壁MK2 mRNA表达的影响。方法 16只雄性新西兰大白兔给予高脂饮食8周后,随机分为高脂血症组(n=8)和烟酸组(n=8),高脂血症组继续饲以高脂饲料6周,烟酸组在高脂饮食基础上给予烟酸[200 mg/(kg.d)]6周。另选8只兔给予普通饮食14周作为正常对照组。14周末处死动物进行主动脉病理学检测,采用实时定量PCR检测各组兔主动脉壁MK2 mRNA的表达。结果与正常对照组相比,高脂血症组总胆固醇和低密度脂蛋白胆固醇水平明显升高,主动脉内膜厚度和斑块面积显著增加,MK2 mRNA表达显著增加(P0.01)。与高脂血症组相比,烟酸组总胆固醇和低密度脂蛋白胆固醇水平显著降低,高密度脂蛋白胆固醇水平升高,主动脉内膜厚度和斑块面积显著减少,MK2 mRNA表达也显著减少(P均0.01)。MK2 mRNA表达量与动脉粥样硬化斑块面积(r=0.919,P0.01)和内膜厚度(r=0.863,P0.01)呈正相关。结论烟酸抗动脉粥样硬化作用除与其降脂作用有关外,还可能与其降低MK2 mRNA水平有关。     

Role of group II secretory phospholipase A2 in atherosclerosis: 1. Increased atherogenesis and altered lipoproteins in transgenic mice expressing group IIa phospholipase A2.

Some observations have suggested that the extracellular group IIa phospholipase A2 (sPLA2), previously implicated in chronic inflammatory conditions such as arthritis, may contribute to atherosclerosis. We have examined this hypothesis by studying transgenic mice expressing the human enzyme. Compared with nontransgenic littermates, the transgenic mice exhibited dramatically increased atherosclerotic lesions when maintained on a high-fat, high-cholesterol diet. Surprisingly, the transgenic mice also exhibited significant atherosclerotic lesions when maintained on a low-fat chow diet. Immunohistochemical staining indicated that sPLA2 was present in the atherosclerotic lesions of the transgenic mice. On both chow and atherogenic diets, the transgenic mice exhibited decreased levels of HDLs and slightly increased levels of LDLs compared with nontransgenic littermates. These data indicate that group IIa sPLA2 may promote atherogenesis, in part, through its effects on lipoprotein levels. These data also provide a possible mechanism for the observation that there is an increased incidence of coronary artery disease in many chronic inflammatory diseases.     

Reduced progression of atherosclerosis in apolipoprotein E-deficient mice with phenylhydrazine-induced anemia.

Epidemiological and experimental studies suggest that circulating erythrocytes play a role in the incidence of coronary heart disease. We investigated the influence of phenylhydrazine (PHZ)-induced anemia on the formation of atherosclerotic lesions in apo E-deficient mice on regular chow and on a high-fat, high-cholesterol diet during 10 weeks. The repeated doses of PHZ caused sustained anemia throughout the study, changes in the physical characteristics of erythrocytes and increased reticulocyte count. The lesions of the anemic animals were smaller than in the controls and this was even more evident in mice fed with the atherogenic diet. A positive correlation was found between circulating red blood cells at the end of the experiment and the area of aortic lesion. There was also a negative association between the lesion and the reticulocyte count. This reduced progression of atherosclerotic lesions is independent of nutritional status or the lipoprotein cholesterol distribution. The results suggest that mechanisms related to the number of circulating red blood cells may have a significant influence on the development of atherosclerosis.     

光学相干断层成像与二维超声对实验性早期动脉粥样硬化诊断的灵敏度比较

目的:通过颈动脉粥样硬化模型评价二维超声与光学相干断层成像(optical coherence tomography,OCT)在早期病变中的检测效果。方法:选择新西兰大耳白兔40只。高脂饮食2周后,进行球囊损伤,术后继续高脂喂养4周。第6周时对兔的右侧颈总动脉进行二维超声检测和OCT检测。检查完成后猝死所有动物,取病理进行HE染色,免疫组化观察巨噬细胞含量。随后处理各组动物,留取动物的颈总动脉组织,进行免疫组化(CD68)及HE染色。结果:病理证实17只(43%)兔出现Ⅲ型病变:OCT证实发生动脉粥样硬化改变15只;超声检测到有内膜增厚7只,检测的灵敏度(即真阳性的检出率,88%vs.41%,P0.01)。病理证实8只兔(20%)出现Ⅱ型病变,OCT发现Ⅱ型病变5只;超声未检测到血管壁有异常改变,灵敏度(62%vs.0%,P0.05)。病理证实13只兔(33%)有Ⅰ型病变:OCT检测发现I型病变5只;超声未检测出管壁有异常改变,灵敏度(38%vs.0%,P0.05)。结论:OCT诊断实验性早期的动脉粥样硬化的灵敏度高于二维超声。     

L-精氨酸抗家兔动脉粥样硬化内皮损伤

将新西兰兔分成三组：正常组、高胆固醇组、高胆固醇加Ｌ－精氨酸组。分别喂养４周和８周。扫描电镜下观察到：高胆固醇组与高胆固醇加Ｌ－精氨酸组相比，内皮细胞排列不规则，细胞间隙银染较粗，内膜损伤和增生明显。说明补充Ｌ－精氨酸可减轻内膜损伤。     

Artery interposed to vein did not develop atherosclerosis and underwent atrophic remodeling in cholesterol-fed rabbits

Autologous vein grafts interposed to arteries are susceptible to the development of accelerated atherosclerosis. The effect of grafted artery interposed to vein on the atherosclerosis development and vascular remodeling is unknown. We investigated, therefore, the morphologic changes of artery grafts to vein in hyperlipidemic rabbits. Left common carotid artery grafts, approximately 5 cm long, were placed in the right external jugular vein position of 24 New Zealand White rabbits. After surgery, rabbits were fed with high lipid diet for 1, 2, 4 and 12 weeks, respectively. Serum lipid levels were measured and the right common carotid artery and grafted left common carotid artery were harvested at above mentioned time points. Serum lipid levels were also measured in six rabbits receiving normal chow. Vessel wall thickness was measured and analyzed by image processing system. Hyperlipidemia occurred in all rabbits fed with high lipid diet. Fatty streak and atherosclerotic plaques were observed and lipid drops enriched in medial smooth muscle cells in control right common carotid arteries 4 weeks after surgery. In the grafted arteries, no fatty streak and atherosclerotic plaque were seen and the vessel wall thickness decreased continuously after surgery (before surgery: 107.32 +/- 4.57 microm; 1 week: 94.50 +/- 5.78 microm*; 2 weeks: 87.00 +/- 5.32 microm*; 4 weeks: 40.17 +/- 5.11 microm*;12 weeks: 18.00 +/- 4.93 microm*, *p <0.05 versus before surgery). Three months after surgery, grafted arteries possess similar structures as that of veins. The artery interposed to vein did not develop atherosclerosis and underwent atrophic remodeling in cholesterol-fed rabbits suggesting that local hemodynamic load was the most important determinant influencing the development of atherosclerosis.     

Upregulation of lectinlike oxidized low-density lipoprotein receptor-1 expression contributes to the vein graft atherosclerosis: modulation by losartan

Vein grafts interposed to arteries are susceptible to the development of accelerated atherosclerosis. The role of lectinlike oxidized LDL (ox-LDL) receptor-1 (LOX-1) expression in the atherosclerotic lesions of vein grafts has not been clarified. The current study was designed to examine the expression of LOX-1 in vein grafts atherosclerosis and the modulating effect of losartan on it. Autologous external jugular veins were grafted to common carotid arteries in 30 male New Zealand White rabbits. After surgery, rabbits were fed with high cholesterol diet (HC), high cholesterol diet plus losartan (10 mg/kg/day, LHC) or regular chow (control, n = 10 in each group) for 12 weeks. LOX-1 expressions in the grafts were examined by immunohistochemistry, semi-quantitative RT-PCR and Western blot. Neointimal hyperplasia was observed in all vein grafts characterized by extensive intimal thickening. Atherosclerotic lesions were found in vein grafts of HC group, which were attenuated by losartan. Losartan also reduced the vein grafts atherosclerotic plaque vulnerability. LOX-1 expression was low in the endothelium and neointima of vein grafts in control group and was significantly increased in the endothelium and atherosclerotic lesions in HC group but not in LHC group. In conclusion, LOX-1 was expressed in endothelium and neointima of autologous vein grafts of rabbits. Increased LOX-1 expression was associated with vein grafts atherosclerosis development. Downregulation of LOX-1 by losartan might contribute to its attenuating effect on vein grafts atherosclerosis.     

Effects of dietary supplementation with fish oil on atherosclerosis and myocardial injury during acute coronary occlusion-reperfusion in diet-induced hypercholesterolemic rabbits.

We studied myocardial injury during acute coronary occlusion-reperfusion and atherosclerosis in rabbits fed a high cholesterol diet with or without fish oil supplementation. New Zealand white male rabbits were divided into 3 groups. Eight control rabbits fed with laboratory standard rabbit chow were group I. In addition to the standard chow, 15 rabbits fed with a 1% cholesterol-enriched diet for 6 weeks were group II, and 10 rabbits fed with a 1% cholesterol-enriched and 10% fish oil supplemented diet for 6 weeks were group III. Acute coronary occlusion was induced by ligating the marginal branch of the left circumflex coronary artery for 1 h, followed by reperfusion for 4 h. Myocardial injury was assessed by tissue creatine kinase activities and amino-nitrogen concentrations from the ischemic (infarct) and nonischemic (normal) myocardium, and the infarct area/risk area ratios of the left ventricle. The surface area of the atherosclerotic lesions of the aorta and pulmonary artery was measured by planimeter. There was significantly more myocardial loss of creatine kinase and amino-nitrogen in the cholesterol-fed rabbits than the controls (p less than 0.01 and 0.02, respectively). The cholesterol and fish oil-treated rabbits had a nonsignificant reduction in myocardial loss of both agents as compared to their corresponding cholesterol-fed ones. The same trend was also found in the infarct area/risk area ratio. Fish oil treated rabbits had a good effect on the reduction of atherosclerotic lesions and tissue cholesterol levels in the aorta and pulmonary artery, but not in the left ventricle.(ABSTRACT TRUNCATED AT 250 WORDS)     

A new murine model for atherosclerosis with inflammation in the periodontal tissue induced by immunization with heat shock protein 60.

It has recently become apparent that the anti-heat shock protein (HSP) antibody plays an important role in the pathogenesis of atherosclerosis. We studied whether immunization with human HSP60 could lead to atherosclerosis in mice. We attempted to induce atherosclerosis in C57BL/6NJcl mice by immunization with human HSP60 under a high-cholesterol diet. The size of fatty streak lesions was significantly enhanced in mice immunized with human HSP60 under a high-cholesterol diet relative to the number in control mice receiving a high-cholesterol diet alone. In addition, these new atherosclerotic model mice showed lesions of inflammation in the periodontal tissue. This new model may thus provide theoretical support for the clinical observation that patients suffering from periodontitis are frequently found to have atherosclerosis. The cytokine ratio of interferon-gamma/interleukin-4 in the high-cholesterol diet group was significantly higher than that in the standard chow group (p<0.05). This suggests the presence of a predominantly Th1-type immune response in atherosclerosis.     

Chronic intermittent hypoxia induces atherosclerosis

RATIONALE: Obstructive sleep apnea, a condition leading to chronic intermittent hypoxia (CIH), is associated with hyperlipidemia, atherosclerosis, and a high cardiovascular risk. A causal link between obstructive sleep apnea and atherosclerosis has not been established. OBJECTIVES: The objective of the present study was to examine whether CIH may induce atherosclerosis in C57BL/6J mice. METHODS: Forty male C57BL/6J mice, 8 weeks of age, were fed either a high-cholesterol diet or a regular chow diet and subjected either to CIH or intermittent air (control conditions) for 12 weeks. MEASUREMENTS AND MAIN RESULTS: Nine of 10 mice simultaneously exposed to CIH and high-cholesterol diet developed atherosclerotic lesions in the aortic origin and descending aorta. In contrast, atherosclerosis was not observed in mice exposed to intermittent air and a high-cholesterol diet or in mice exposed to CIH and a regular diet. A high-cholesterol diet resulted in significant increases in serum total and low-density lipoprotein cholesterol levels and a decrease in high-density lipoprotein cholesterol. Compared with mice exposed to intermittent air and a high-cholesterol diet, combined exposure to CIH and a high-cholesterol diet resulted in marked progression of dyslipidemia with further increases in serum total cholesterol and low-density lipoprotein cholesterol (124 +/- 4 vs. 106 +/- 6 mg/dl; p < 0.05), a twofold increase in serum lipid peroxidation, and up-regulation of an important hepatic enzyme of lipoprotein secretion, stearoyl-coenzyme A desaturase-1. CONCLUSIONS: CIH causes atherosclerosis in the presence of diet-induced dyslipidemia.