卡托普利、缬沙坦对兔动脉粥样硬化斑块的干预作用

目的观察高胆固醇饮食造成兔大动脉粥样斑块形成过程中卡托普利和缬沙坦对大动脉粥样斑块形成的干预作用。方法30只健康雄性新西兰兔随机分为高脂饮食组(A组),高脂饮食加卡托普利组(B组),高脂饮食加缬沙坦组(C组)和对照组(D组)喂养10周后,行超声检测腹主动脉内膜中膜的厚度。并行病理观察血管内膜以及血管内皮细胞情况。结果A组腹主动脉壁粥样斑块形成,血管内膜增厚;B组和C组血管壁有少量粥样斑块形成,血管内膜增厚均较A组明显减轻(P<0.01)。结论卡托普利和缬沙坦具有抗高胆固醇血症致动脉壁粥样斑块形成的确切效果。     

高脂饮食联合球囊内皮损伤术建立兔腹主动脉粥样硬化模型的可行性研究

目的:探讨高脂饮食联合球囊内皮损伤术在建立兔腹主动脉粥样硬化模型中的可行性以及应用价值。方法:24只新西兰大耳白兔,分为假手术组、单纯高脂饮食组、联合损伤4周组以及8周组共4组,每组6只。联合损伤两组均接受高脂喂养联合球囊内皮损伤术,并分别在术后4和8周处死。所有动物处死前行腹主动脉血管超声以及DSA检查,评估血管狭窄程度,并做斑块病理分析。结果:与单纯高脂饮食组比较,损伤8周组的斑块厚度(404.86μm∶67.89μm,P0.05)以及内膜增生指数(0.70∶0.09,P0.05)均显著升高,与4周组相比,损伤8周组动脉内膜增生程度进一步加重(P0.05)。损伤组斑块内可见大量中膜平滑肌细胞向内膜迁移增生,新生内膜见较多泡沫细胞,表面覆盖纤维细胞。结论:采用高脂饮食联合球囊内皮损伤术的方法建立兔腹主动脉粥样硬化模型简单易行、周期短、成功率高,斑块病理表现接近于人,可为研究人类的动脉粥样硬化疾病提供一种良好动物模型。     

阿司匹林对小型猪动脉粥样硬化的影响

目的探讨阿司匹林对早期动脉粥样硬化的干预作用。方法健康小型猪22头,随机分为对照组(n=6):给予正常猪饲料;高脂组(n=8):给予3%胆固醇高脂饮食;阿司匹林组(n=8):给予3%胆固醇高脂饮食 阿司匹林150 mg/d。高脂饮食4个月和6个月时,每组随机处死一半,定量测量动脉粥样硬化斑块厚度和斑块面积。结果3.0%胆固醇高脂饮食4个月就可以引起小型猪明显的动脉粥样硬化。高脂饮食4个月时,高脂组冠状动脉斑块厚度和截面积分别为107.2±45.7μm和0.113±0.05 mm2;阿司匹林组主动脉粥样硬化面积无明显减少,冠状动脉斑块厚度和截面积分别为74.2±24.7μm和0.093±0.05 mm2,与高脂组相比无统计学差异。高脂饮食6个月时,高脂组冠状动脉动脉粥样硬化斑块厚度为152.9±86.1μm、斑块/中膜厚度比0.85±0.49、斑块截面积为0.188±0.207 mm2、内膜/中膜面积比0.235±0.249;阿司匹林组主动脉粥样硬化面积明显减少,冠状动脉粥样硬化斑块厚度(47.8±19.8μm)、斑块/中膜厚度比(0.33±0.09)、斑块截面积(0.017±0.012 mm2)、内膜/中膜面积比(0.030±0.019),均明显低于高脂组(P<0.05或P<0.01)。结论阿司匹林对早期动脉粥样硬化有抑制作用。     

瑞舒伐他汀对ApoE-/-小鼠动脉粥样斑块中凋亡相关蛋白的影响

目的观察瑞舒伐他汀对Apo E-/-小鼠动脉粥样硬化斑块凋亡相关蛋白Bcl-2和Caspase-3表达的影响。方法 10只C57小鼠作为对照组,给予普通饮食,同品系22只Apo E-/-小鼠随机分为模型组(n=11)、干预组(n=11),高脂喂养8 w后,干预组给予瑞舒伐他汀悬液灌胃,模型组给予等量生理盐水。继续喂养12 w后所有老鼠处死,全自动生化仪检测血清血脂,光学显微镜观察各组小鼠主动脉斑块形态及面积,免疫组化法检测动脉粥样斑块Bcl-2和Caspase-3蛋白的表达。结果与对照组相比较,模型组总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)明显升高(P0.05),高密度脂蛋白胆固醇(HDL-C)明显降低(P0.05);主动脉可见明显粥样斑块;Bcl-2表达明显减少,Caspase-3表达明显增多(P0.05)。与模型组比较,TC、TG、LDL-C明显降低(P0.05);干预组小鼠动脉粥样斑块面积减小(P0.05),Bcl-2表达明显增多,Caspase-3表达明显减少(P0.05)。结论高脂饮食可引起Apo E-/-小鼠主动脉凋亡相关蛋白Bcl-2和Caspase-3的变化,瑞舒伐他汀可以通过上调Bcl-2、下调Caspase-3的表达,抑制Apo E-/-小鼠动脉粥样硬化斑块的进展。     

艾赛布考抑制兔动脉粥样硬化的作用及可能机制

目的:艾赛布考是普罗布考代谢稳定的衍生物,具有抗氧化、抗炎、抗增殖特性。本研究旨在探讨艾赛布考对高胆固醇血症兔腹主动脉损伤后动脉粥样硬化发展的影响。方法:45只雄性新西兰兔随机分为对照组、艾赛布考组、普罗布考组3组,每组15只,分别给予高脂饮食(对照组),高脂饮食+1%艾赛布考(艾赛布考组)或1%普罗布考(普罗布考组),2周后,行腹主动脉内膜球囊损伤术,继续药物干预10周。12周末,行血管内超声评价三组兔腹主动脉粥样硬化斑块面积和斑块负荷;通过免疫组织化学法观察斑块内巨噬细胞的含量,免疫组织化学法、实时定量聚合酶链式反应分别检测斑块组织内炎症因子细胞间黏附分子-1、单核细胞趋化蛋白-1、基质金属蛋白酶-9蛋白及信使核糖核酸的表达。结果:与对照组相比,艾赛布考组兔血中低密度脂蛋白胆固醇及氧化应激水平显著降低,腹主动脉粥样硬化斑块内巨噬细胞含量及炎症因子表达也降低,斑块面积及斑块负荷显著减少(P均0.01)。与普罗布考组相比,艾赛布考组兔腹主动脉斑块面积及斑块负荷降低更加显著,差异具有统计学意义(P均0.01)。结论:艾赛布考通过调脂、抗炎、抗氧化作用,抑制内膜损伤后动脉粥样硬化进展。     

原肌球蛋白4抗体靶向动脉粥样硬化合成型血管平滑肌细胞体内磁共振成像的实验研究

目的 观察合成型血管平滑肌细胞(VSMC)标记蛋白原肌球蛋白4(TPM-4)在动脉粥样硬化斑块形成过程中的表达变化及分布，探讨靶向合成型VSMC体内MRI的可行性。方法 选择雄性载脂蛋白E(apoE^-/-)小鼠45只为实验组(高脂饲料喂养),雄性6周龄C57BL/6小鼠25只为对照组(普通饲料喂养)。2组小鼠分别于不同时间点取腹主动脉进行苏木精-伊红、免疫组织化学及Masson染色。从实验组随机选取建模成功apoE^-/-小鼠各10只分别为靶向探针组[anti-TPM-4-单纯超微超顺磁性氧化铁纳米颗粒(USPIO)]及单纯USPIO组，在探针注射前及注射24 h后采用7.0 T磁共振采集腹主动脉图像，观察信号变化，扫描完成后取腹主动脉标本进行病理学验证。结果 对照组小鼠无斑块形成，实验组小鼠不同时间点斑块内均可见TPM-4表达，阳性表达主要在斑块周围及胶原纤维分布区域。斑块内TPM-4和胶原纤维阳性面积与斑块面积呈正相关(r=0.875,P<0.01;r=0.811,P<0.01)。靶向探针组腹主动脉斑块T₂...     

肺炎衣原体感染增强C57BL/6J小鼠氧化应激加速动脉粥样硬化发展

目的研究肺炎衣原体感染对C57BL/6J小鼠氧化应激及动脉粥样硬化形成的影响。方法48只C57BL/6J小鼠分为感染高脂组、高脂组、感染组和对照组,每组12只,喂养40周,作血清抗CP抗体和血脂水平检测,取主动脉根部标本分析动脉粥样硬化斑块面积,主动脉弓部标本检测超氧阴离子的产生。结果所有接种CP的小鼠,抗CP抗体IgG滴度均大于1∶128,未接种CP者抗CP抗体阴性,感染高脂组和高脂组小鼠血清总胆固醇、低密度脂蛋白水平明显高于对照组,感染高脂组、高脂组和感染组超氧阴离子的产生明显高于对照组[(1974.25±650.49)、(701.00±105.16)、(455.62±77.54)counts·mg-1·min-1比(142.25±31.82)counts·mg-1·min-1,P<0.001],氧化荧光染料定位分析发现感染高脂组、高脂组和感染组小鼠主动脉超氧阴离子产生明显增多,且感染高脂组小鼠平均粥样硬化斑块面积大于高脂组[(135249±43748)μm2比(96378±30945)μm2,P<0.05]。结论肺炎衣原体感染可加速高脂饮食C57BL/6J小鼠的主动脉粥样硬化发展,并引起C57BL/6J小鼠主动脉超氧阴离子产生增多,提示活性氧产生增多、氧化应激增强可能是肺炎衣原体感染加速动脉粥样硬化发展的机制之一。     

消瘀片消退兔腹主动脉粥样斑块作用的研究

目的 观察消瘀片对兔腹主动脉粥样斑块的消退作用。方法 采用高脂饮食８ｗ加主动脉内膜剥脱术帛成兔腹主动脉粥样硬化模型,通过血管腔内超声技术、光镜和电镜,检查口服消瘀片１６ｗ后兔腹主动脉粥样斑块的消长变化。结果 血管腔内超声检查显示,粥样硬化组管壁呈弥漫性增厚,腔内有环形或半月状粥样斑块低回声区,用消瘀片治疗后,管壁增厚不明显,仅可见散在或短弧形粥样斑块回声区,粥样斑块厚度和斑块面积与粥样硬化组相比明     

降脂药物对小鼠颈动脉粥样硬化斑块内基质金属蛋白酶3表达的影响

目的研究降脂药物对小鼠颈动脉粥样硬化斑块内基质金属蛋白酶(MMP)-3表达的影响,分析降脂药物对颈动脉粥样硬化斑块的作用。方法对照组:10只28周龄SPF级普通雄性小鼠,给予普通饮食,喂养12 w。实验组:20只28周龄载脂蛋白E基因(Apo E)敲除雄性小鼠,给予高脂饮食,喂养12 w后,随机分为非治疗组(10只),直接进入实验程序;治疗组(10只)给予阿托伐他汀钙片灌胃+普通饮食,继续喂养12 w,进入实验程序:检测各组小鼠血清MMP-3,并分离各组小鼠颈动脉,通过免疫组化分析斑块内MMP-3的表达。结果与对照组比较,非治疗组血清MMP-3明显升高(P0.01)。非治疗组斑块内MMP-3的表达明显增加(P0.01)。与非治疗组比较,治疗组血清MMP-3明显下降(P0.05)。治疗组斑块内MMP-3的表达明显下降(P0.05)。结论动脉粥样硬化发展过程中,MMP-3起到重要作用,动脉粥样硬化斑块的不稳定与MMP-3的表达增高密切相关。降脂治疗可使斑块内MMP-3降低,使斑块缩小。     

金属硫蛋白对ApoE基因缺陷小鼠血脂、动脉粥样硬化及主动脉SR-AⅠ表达的影响

目的观察金属硫蛋白对ApoE基因缺陷小鼠血脂、动脉粥样硬化以及主动脉AⅠ型清道夫受体(SR-AⅠ)表达的影响。方法将20只6周龄雄性ApoE基因缺陷小鼠随机分为高脂模型组、金属硫蛋白组各10只,高脂饮食喂养13周;取10只野生雄性小鼠作为正常对照组,正常饮食喂养13周。13周后摘眼球取血测定血清总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)。处死小鼠后取主动脉,HE染色及SR-AⅠ免疫组织化学染色后观察主动脉血管壁形态学变化;用Western Blot和RT-PCR法检测主动脉壁组织中的SR-AⅠ蛋白和mR-NA表达。结果金属硫蛋白组TC、TG、LDL-C与高脂高脂模型组比较P均>0.05;金属硫蛋白组小鼠肝肾功能和肌酸磷酸激酶指标与高脂模型组相比P均>0.05。与正常对照组相比,高脂模型组主动脉粥样硬化病变程度明显加重,主动脉壁SR-AⅠ蛋白和mRNA表达均明显增加(P均<0.05);与高脂模型组相比,金属硫蛋白组主动脉粥样硬化程度减轻,SR-AⅠ蛋白和mRNA的表达均降低(P均<0.05)。结论金属硫蛋白对ApoE基因缺陷小鼠血脂无明显影响,但可降低其主动脉壁SR-AⅠ蛋白和mRNA,降低粥样硬化病变程度。     

瑞舒伐他汀对载脂蛋白E基因敲除小鼠动脉粥样硬化的影响

目的 探讨瑞舒伐他汀对载脂蛋白E基因敲除(apoE-/-)小鼠主动脉粥样硬化的影响.方法 取apoE-/-小鼠18只建立动脉粥样硬化模型,C57BL/6小鼠12只为对照组.apoE-/-小鼠予高脂饲料,C57BL/6小鼠予普通饲料.12周后,随机抽取C57BL/6小鼠和apoE-/-小鼠各6只,判断是否成模.将成模后余下的12只apoE-/-小鼠随机分为模型组和瑞舒伐他汀治疗组(瑞舒伐他汀10 mg·kg-1·d-1灌胃),每组6只.余下的6只C57BL/6小鼠作为对照组.再过12周后处死小鼠,行血脂及主动脉HE、Masson、油红O染色观察动脉斑块,免疫组织化学方法检测主动脉组织平滑肌肌动蛋白(α-SMA)、转化生长因子β1(TGF-β1)、巨噬细胞表面分子-3(Mac-3)表达.结果 模型组小鼠胆固醇、低密度脂蛋白水平均高于对照组(P均＜0.01),甘油三酯水平与对照组比较差异无统计学意义.模型组小鼠主动脉组织内可见明显动脉粥样硬化斑块形成,α-SMA、TGF-β1和Mac-3表达均较高于对照组(P均＜0.01).瑞舒伐他汀治疗组小鼠胆固醇、低密度脂蛋白、甘油三酯水平与模型组比较差异无统计学意义,但斑块内脂肪含量少于模型组,胶原含量多于模型组.治疗组α-SMA表达与模型组比较差异无统计学意义,治疗组TGF-β1、Mac-3表达均低于较模型组(P均＜0.01).结论 瑞舒伐他汀可以减轻apoE-/-小鼠动脉粥样硬化模型中的脂质沉积和炎症反应,可以增加其胶原含量,利于斑块的稳定,具有抗动脉粥样硬化的作用,对血脂无影响.

Abstract：

Objective To investigate the effect of rosuvastatin on atherosclerosis in apoE-knockout ( apoE - / - ) mice. Methods Eighteen 6-week-old apoE - / - mice fed with high fat diet were used as atherosclerosis models, twelve 6-week-old C57BL/6 mice fed with normal diet were used as control. After twelve weeks, six apoE -/ - mice were used to observe the formation of atherosclerosis. Another 12 apoE -/- mice were divided into placebo treated group (n =6) and rosuvastatin group (n =6,10 mg· kg-1 ·d -1 per gavage) and treated for 12 weeks. Then, blood was collected for measuring lipid, aorta was prepared for morphologic study (HE, Oil red O, Masson) and immunohistochemical analysis (α-smooth activor protein, transforming growth factor β1, macrophage surface molecule-3 ). Results Serum cholesterol and low density lipoprotein levels were significantly higher in apoE -/- mice fed with high fat diet than in C57/ BL6 mice( all P ＜0. 01 )while triglyceride level was similar between the two groups, these were not affected by rosuvastatin. Similarly, atherosclerotic lesion area in apoE -/ - mice fed with high fat diet was also not significantly reduced by rosuvastatin, while lipid deposition could be significantly reduced and collagen deposition could be significantly increased in the aortic atherosclerotic lesions by treatment with rosuvastatin.Upregulated TGF-β1 and Mac-3 expression in the aortic atherosclerotic lesions in apoE -/- mice fed with high fat diet could also be significantly reduced by rosuvastatin (all P ＜ 0. 01 ), suggesting reduce inflammatory responses in the atherosclerotic lesion and stable atherosclerotic plaque post rosuvastatin treatment. Conclusion Reducing inflammatory responses and stabilizing plaque properties might contribute to the anti-atherosclerosis effects of rosuvastatin in mice high fat diet fed apoE -/- mice.     

Low carbohydrate, high protein diet promotes atherosclerosis in apolipoprotein E/low-density lipoprotein receptor double knockout mice (apoE/LDLR(-/-))

Although in apoE/LDLR(-/-) mice atherosclerotic plaques develop spontaneously, various atherogenic diets (e.g. Western diet) are frequently used to accelerate the disease in this model. The objective of this study was to compare the effects on atherosclerosis of Western diet and other types of high-fat, high cholesterol, hypertriglyceridemic diets with the effects of the low carbohydrate, high protein (LCHP) diet. 16-18 week old mice with pre-established atherosclerosis were assigned to experimental groups and fed for the next 10 weeks with control diet, margarine diet (margarine 7%), hypertrigliceridemic diet (fructose 62%), high-fat diet (Western diet), high cholesterol diet (egg yolk diet) or with LCHP diet. No differences in body weight were observed among experimental groups. Plasma cholesterol concentration was significantly increased in egg yolk diet- and LCHP diet-fed apoE/LDLR(-/-) mice as compared to other types of diets. Plasma concentration of triacylglycerols was significantly elevated in egg yolk diet- and LCHP diet-fed apoE/LDLR(-/-) mice. The area of atherosclerotic plaques in the aortic root was substantially increased in LCHP diet-fed mice as compared to other types of diets. Furthermore, in brachiocephalic arteries of LCHP diet-fed mice there was evidence of plaque rupture. In conclusion, the LCHP diet promoted atherosclerosis in apoE/LDLR(-/-) mice more intensively than classical Western diet and favored the development of unstable lesions.     

In vivo uptake of radiolabeled MDA2, an oxidation-specific monoclonal antibody, provides an accurate measure of atherosclerotic lesions rich in oxidized LDL and is highly sensitive to their regression

To determine whether labeled antibodies against oxidized LDL (OxLDL) offer advantages for quantifying atherosclerosis, we compared in vivo aortic uptake of (125)I-labeled MDA2, a monoclonal antibody against malondialdehyde-lysine epitopes), atherosclerotic surface area, and aortic weight in Watanabe heritable hyperlipidemic and New Zealand White rabbits and in low density lipoprotein receptor-deficient (LDLR(-/-)) and apolipoprotein E-deficient (apoE(-/-)) mice. Absolute and specific uptakes of (125)I-MDA2 were significantly greater in plaque than in normal aortas. Uptake of (125)I-MDA2 significantly correlated with aortic weight and percent atherosclerotic surface area in rabbits and mice. To assess whether (125)I-MDA2 uptake reflects changes in lesion content of OxLDL, in a separate study, extensive atherosclerosis was induced in 4 groups of LDLR(-/-) mice by feeding them a high fat/cholesterol diet for 6 months. A baseline group was euthanized at this time. The remaining groups were fed "regression" diets (chow or chow+1% vitamin E+0.05% vitamin C) or the high fat/cholesterol diet for 6 more months. When atherosclerosis was measured as percent surface area or aortic weight, there was strong progression in the high fat/cholesterol group, moderate progression in the chow group, and no progression in the chow+vitamin E+vitamin C group compared with the baseline group. The (125)I-MDA2 method also yielded a significant increase in atherosclerosis in the high fat/cholesterol group but significant decreases in the chow and chow+vitamin E+vitamin C groups. Immunocytochemistry showed fewer oxidation-specific epitopes in lesions from the chow and chow+vitamin E+vitamin C groups. Thus, the uptake of (125)I-MDA2 correlates well with traditional measures of atherosclerosis but also reflects reduced plaque OxLDL content after hypocholesterolemic intervention.     

Orchidectomy, but not ovariectomy, regulates angiotensin II-induced vascular diseases in apolipoprotein E-deficient mice

In humans, the incidence and severity of abdominal aortic aneurysms (AAA) are greater in males than in females. Chronic infusion of angiotensin II (AngII) into apolipoprotein E-deficient (apoE(-/-)) mice promotes atherosclerosis and causes the formation of AAAs. Just as human males are more susceptible to developing AAAs, male mice are more susceptible to AngII-induced AAAs. We hypothesized that sex steroid hormones mediate gender differences in AngII-induced AAA through regulation of the renin-angiotensin system. To define the role of ovarian hormones, female apoE(-/-) mice were subjected to ovariectomy or sham operation and infused with AngII (1000 ng/kg x min) for 28 d. Ovariectomy had no effect on AngII-induced atherosclerosis, nor did it influence the incidence or severity of AAA. To define the role of testicular hormones, male apoE(-/-) mice were subjected to orchidectomy (orx) or sham operation and infused with AngII (1000 ng/kg x min) for 28 d. Orx resulted in a profound reduction in AAA incidence (85% vs. 18%, sham vs. orx; P = 0.003) to the level observed in females (25%). However, orx had no effect on AngII-induced reductions in plasma renin concentration or spleen AngII receptor density. In contrast, orx resulted in an increase in atherosclerosis (0.46 +/- 0.07 vs. 1.20 +/- 0.21 mm(2), sham vs. orx; P = 0.002). These results suggest that estrogen does not mediate gender differences in AngII-induced AAA. In contrast, androgens mediate a higher incidence of AngII- induced AAA, through mechanisms that do not appear to involve circulating renin or angiotensin receptor density.     

Site-specific antiatherogenic effect of probucol in apolipoprotein E-deficient mice

-The lipid-lowering antioxidant probucol can inhibit atherosclerosis in animals and restenosis in humans. However, probucol has been shown to promote atherosclerosis in the aortic root of apolipoprotein E-deficient (apoE-/-) mice. In the current study, we examined the effects of probucol on both lesion formation at 4 sites along the aorta and lipoprotein oxidation in the plasma and aortas of apoE-/- mice receiving a diet containing 21.2% (wt/wt) fat and 0. 15% (wt/wt) cholesterol without or with 1% (wt/wt) probucol. After 6 months, controls had developed lesions at all sites investigated. Lesion development was strongly (P=0.0001) affected by probucol, but this effect was not uniform: lesion size was increased in the aortic root but significantly decreased in the arch, the descending thoracic aorta, and proximal abdominal aorta. Plasma and aortas of probucol-treated mice contained high concentrations of probucol and its metabolites (bisphenol and diphenoquinone); increased vitamin C; markedly decreased very low density lipoprotein (but not low density lipoprotein and high density lipoprotein); and decreased cholesterol, cholesteryl esters, triglycerides, vitamin E, and oxidized lipids compared with controls. Interestingly, probucol treatment did not decrease the proportion of aortic lipids that were oxidized. Plasma vitamin C and bisphenol, but not probucol, protected plasma lipids from ex vivo oxidation by peroxyl radicals. These results show that as in other species, probucol can inhibit lesion formation in most parts of the aorta of apoE-/- mice. This effect may involve lipid oxidation-independent mechanisms localized within the vessel wall as well as lipid lowering.     

Reduced atherosclerosis in chow-fed mice expressing high levels of a catalytically inactive human hepatic lipase

Increased expression of catalytically inactive hepatic lipase (ciHL) lowers remnants and low-density lipoproteins (LDL) and may reduce atherosclerosis in mice lacking both LDLreceptors (LDLR) and murine (m) HL. However, in a previous study, ciHL expression failed to reduce atherosclerosis but increased liver fat accumulation after a 3-month high-fat diet, suggesting that diet-induced metabolic changes compromised the antiatherogenic effects of ciHL. Therefore, we hypothesized that reduced dietary fat would reduce atherosclerosis in ciHL expressing mice. Mice lacking both LDLR and mHL, alone, or expressing ciHL were fed a low-fat (chow) diet for 9 months to match the cumulative cholesterol exposure resulting from a 3-month high-fat diet. Plasma lipids and lipoproteins as well as atherosclerosis were determined at sacrifice. Also, liver expression of receptors and proteins contributing to cholesterol delivery including the LDLreceptor related protein (LRP), scavenger receptor (SR)-B1 and apoE were determined. At 9 months, ciHL expression reduced plasma cholesterol by approximately 20% and atherosclerosis by 79% (from 2.67+/-0.61% of aortic surface, Ldlr-/-hl-/-, n=9, to 0.55+/-0.32% of aortic surface, Ldlr-/-hl-/-ciHL, n=7, P=0.01). Also, LRP-expression increased approximately 4-fold, whereas SR-B1 and apoE remained unchanged. These results demonstrate that ciHL expression reduces atherosclerosis. Also, these results demonstrate that ciHL increases LRP expression and suggest increased LRP-mediated lipoprotein clearance as a pathway for ciHL-mediated atherosclerosis reduction.     

Angiotensin II, type 2 receptor is not involved in the angiotensin II-mediated pro-atherogenic process in ApoE-/- mice

OBJECTIVE: Angiotensin II (Ang II) accelerates atherogenesis in ApoE mice via the angiotensin II, type 1 receptor (AT1) while the type 2 receptor (AT2) is suggested to counteract atherogenesis. To confirm and further explore this possibility, we studied the effect of AT2 receptor antagonism on Ang II-accelerated atherosclerosis. METHODS: ApoE mice were fed a standard or high cholesterol diet (1.25%) for 4 weeks. Mice on each diet were treated with either Ang II (0.5 microg/kg per min) or Ang II in combination with PD123319 (3 mg/kg per day). Plaque distribution was assessed by en face quantification of the thoracic aorta and in cross-sections of the aortic root. Mean arterial pressure (MAP) was measured. AT1 and AT2 receptor expression were analysed using real-time polymerase chain reaction (PCR) and the localization of the AT2 receptor protein confirmed with immunohistochemistry. RESULTS: Ang II infusion increased MAP only in mice on a standard diet (P < 0.001). Regardless of diet, Ang II-infused mice had 22-30 times increased plaque area in the thoracic aorta (P < 0.001 for both). Ang II had no effect on plaque in the aortic root. Plaque area was not affected by PD123319. AT2 receptor was heavily expressed in the plaques and increased six- to ninefold by a high cholesterol diet and Ang II infusion (P < 0.01). CONCLUSION: Ang II increases the extent of atherosclerosis in ApoE mice. Despite up-regulation of the AT2 receptor, we found no support for an effect of the AT2 receptor on atherogenesis in this model.     

Fish oil increases antioxidant enzyme activities in macrophages and reduces atherosclerotic lesions in apoE-knockout mice

OBJECTIVES: The molecular and cellular mechanisms that fish oil (FO) exerts its physiological function are complicated. The present study brings evidence on the in vivo effect of FO on the development of atherosclerosis in apolipoprotein E knockout (apoE(-/-)) mice. We also test the hypothesis that the modulation of the cellular oxidative stress and antioxidant status contributes to the anti-atherosclerotic effect of FO. METHODS AND RESULTS: ApoE(-/-) mice were fed a diet rich either in FO or corn oil (CO) for 10 weeks. Both FO and CO had a plasma triacylglycerol-raising effect in apoE(-/-) mice, whereas aortic atherosclerotic lesions were significantly reduced in the mice that had consumed a high FO diet compared to those fed a high CO diet. The levels of hepatic superoxide dismutase (SOD) and catalase (CAT) activities were remarkably higher in the mice fed the FO diet than in mice fed the CO diet and the control diet. We then investigated the effects of FO and CO on the production of superoxide anion (O2*-)) and reactive oxygen species (ROS) in cultured J774 macrophages. Antioxidant status was assessed by the determination of antioxidant enzyme activities. Both FO and CO induced high levels of O2*-) and total ROS at a short time in macrophages. However, only the FO group restored the induction of O2*-) and ROS to near basal levels after oil treatment for 24 h. Throughout the time course experiments, antioxidant enzyme activities in the FO group mostly displayed a greater increase than in the corresponding CO group after the same time period of oil treatment. CONCLUSIONS: In the present study, FO reduced the formation of atherosclerotic lesions in the aortic arteries of apoE(-/-) mice not through any lipid-lowering effect. The protective role of FO in the development of atherosclerosis may result from its antioxidative defense mechanism through the induction of antioxidant enzyme activities.     

Disruption of tumor necrosis factor-alpha gene diminishes the development of atherosclerosis in ApoE-deficient mice

Inflammatory cytokines, including tumor necrosis factor-alpha (TNF-alpha) have been implicated in atherogenesis. However, the precise role of TNF-alpha in atherogenesis is still unclear. To examine the effect of TNF-alpha on atherogenesis, we generated compound-deficient mice in apolipoprotein E (apoE) and TNF-alpha (apoE-/-/TNF-alpha-/-) and compared them with apoE-/- mice. Although serum total cholesterol levels were markedly elevated in both apoE-/-/TNF-alpha-/- and apoE-/- mice compared to wild-type mice, no differences were observed between apoE-/-/TNF-alpha-/- and apoE-/- mice. The atherosclerotic plaque area in the aortic luminal surface of apoE-/-/TNF-alpha-/- mice (n=8, 3.1+/-0.4%) was significantly smaller than that of apoE-/- mice (n=7, 4.7+/-0.4%, p<0.001) despite the lack of difference in serum cholesterol levels. The atherosclerotic lesion size in the aortic sinus of apoE-/-/TNF-alpha-/- mice (n=10, 5.1+/-0.3 x 10(5)microm(2)) was also significantly smaller than that of apoE-/- mice (n=11, 7.0+/-0.3 x 10(5)microm(2), p<0.0001). RT-PCR analysis indicated that the expression levels of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and monocyte chemoattractant protein-1 (MCP-1) were significantly higher in apoE-/- than apoE-/-/TNF-alpha-/- mice. Macrophages from apoE(-/-) mice showed higher uptake level of oxidized LDL and increased expression level of scavenger receptor class A (SRA) compared to those from apoE-/-/TNF-alpha-/- mice. These results indicate that TNF-alpha plays an atherogenic role by upregulating the expressions of ICAM-1, VCAM-1 and MCP-1 in the vascular wall, and by inducing SRA expression and oxidized LDL uptake in macrophages.