慢性间歇低氧激活载脂蛋白E基因敲除小鼠补体系统促进动脉粥样硬化进展的研究

目的:观察慢性间歇低氧(CIH)下载脂蛋白E(ApoE-/-)小鼠补体系统激活情况,探讨CIH激活补体系统的机制.方法:将18只ApoE-/-小鼠,随机分为常氧组(n=9)和低氧组(n=9),给予所有小鼠高脂饮食喂养,以电脑程序控制低氧舱内氧浓度在5％～21％内循环以建立CIH诱导的动脉粥样硬化模型.HE染色检测斑块面...     

有氧运动对高同型半胱氨酸血症载脂蛋白E基因敲除小鼠动脉粥样硬化的影响

目的观察有氧运动训练对高同型半胱氨酸血症(HHcy)小鼠血浆同型半胱氨酸水平(Hcy)的影响,探讨有氧运动是否能够延缓HHcy致动脉粥样硬化。方法 6周龄雌性载脂蛋白E基因敲除(ApoE-/-)小鼠随机分为三组:对照组、HHcy组和HHcy+有氧运动组。饮用水中加入Hcy制作HHcy模型。HHcy+有氧运动组在1周适应性训练后进行8周跑台训练(0°,15 m/min,60 min/d,每周训练5天)。采用酶法检测血浆Hcy和血脂水平。主动脉根部切片,油红O染色,计算动脉粥样硬化斑块面积。结果 HHcy组血浆Hcy水平与对照组相比明显增高(20.88±5.79μmol/L比7.80±1.10μmol/L,P=0.001),HHcy+有氧运动组血浆Hcy水平较HHcy组明显下降(14.01±2.30μmol/L比20.88±5.79μmol/L,P=0.016)。三组之间体重增长、饮水量及血浆总胆固醇、低密度脂蛋白胆固醇、高密度脂蛋白胆固醇、甘油三酯水平无显著性差异。与对照组相比,HHcy组动脉粥样硬化斑块面积[(9.24±9.02)×10-4 mm2比(15.55±4.64)×10-4 mm2,P=0.034]及斑块负荷(12.20%±12.09%比19.86%±6.30%,P=0.047)明显增加,HHcy+有氧运动组较HHcy组斑块面积[(15.55±4.64)×10-4mm2比(8.62±7.55)×10-4mm2,P=0.024]及斑块负荷(19.86%±6.30%比10.62%±9.06%,P=0.021)明显降低。结论有氧运动可以降低HHcyApoE-/-小鼠血浆Hcy水平,延缓动脉粥样硬化进展,该作用独立于血脂水平的改变。     

细胞外基质金属蛋白酶诱导因子和尿激酶型纤溶酶原激活物在载脂蛋白E基因敲除小鼠主动脉粥样硬化斑块中的表达

目的探讨细胞外基质金属蛋白酶诱导因子(EMMPRIN)与尿激酶型纤溶酶原激活物(uPA)在载脂蛋白E基因敲除(ApoE-/-)小鼠主动脉粥样硬化斑块中的表达,并探讨两者的相互关系。方法研究对象采用ApoE-/-小鼠,共喂养18周,分别于6周、10周、14周和18周4个时间点处死小鼠行HE染色切片观察动脉粥样硬化斑块形态;并采用RT-PCR及Western blot检测主动脉粥样硬化斑块内EMMPRIN和uPA的表达。结果成功建立动脉粥样硬化模型;在主动脉粥样硬化斑块中检测到EMMPRIN和uPA表达均增高,与普通饮食组比较有统计学意义(P<0.05)。EMMPRIN和uPA表达随喂养时间延长而增高。结论 EMMPRIN和uPA在ApoE-/-小鼠主动脉粥样硬化斑块中随着斑块病变程度的严重性增加表达增高,两者可能共同参与粥样硬化斑块的发生发展过程。     

阿托伐他汀对高同型半胱氨酸血症诱发动脉粥样硬化的干预作用

目的:观察阿托伐他汀对动脉粥样硬化斑块的影响, 并对其作用机制进行初步探讨。方法: 20 g/L L-蛋氨酸灌胃法建立ApoE基因敲除小鼠高同型半胱氨酸血症(hyperhomocysteinemia,HHcy)模型,按实验分组, 给予不同剂量阿托伐他汀治疗1个月后,用高效液相色谱荧光法测定血浆同型半胱氨酸(Hcy)水平,相差显微镜下观察小鼠主动脉根部病理学形态,免疫组织化学法检测主动脉血管平滑肌SM-α-actin的表达,TUNEL法检测小鼠主动脉斑块中的细胞凋亡指数,NBT及光泽精化学发光法检测血管局部活性氧(reactive oxygen species,ROS)水平, 光泽精化学发光法检测主动脉血管NADPH氧化酶(NADPH oxidase,Nox)活性,Western印迹法检测Nox4蛋白表达。结果: ApoE-/-小鼠蛋氨酸喂养3个月后,血浆Hcy水平升高,AS斑块形成。阿托伐他汀治疗1个月后,呈剂量依赖性地降低小鼠血浆Hcy水平,延缓AS病变的进程,减少斑块内凋亡细胞数量,降低了血管壁局部ROS水平,Nox活性及Nox4蛋白表达（均P<0.05）。结论: 阿托伐他汀治疗后,HHcy ApoE-/-小鼠AS病变进程延缓,其作用机制与其下调Nox4来源的ROS水平、抑制血管内皮细胞凋亡有关。     

多聚二磷酸腺苷核糖合成酶抑制剂对血管紧张素Ⅱ刺激培养心肌细胞异常基因表达的阻止作用

目的:观察多聚二磷酸腺苷(ADP)核糖合成酶(PARP)抑制剂对血管紧张素Ⅱ(AngⅡ)刺激的乳鼠心脏心肌重构的预防作用.方法:新生大鼠心肌细胞原代培养,传代,用PARP抑制剂3-AB预处理细胞,观察PARP抑制剂对AngⅡ诱导心肌细胞PARP激活、PARPl表达,细胞内ROS产生和c-fos,ANP,β/aMHC基因表达的影响.结果:AngⅡ显著诱导心肌细胞PARP激活,ROS产生增加,PARPl、c-los、β/a-MHC、ANP基因表达增加.给予3-AB预处理可显著抑制AngⅡ诱导的上述变化.结论:AngⅡ可以诱导培养的心肌细胞内PARP激活,PARPl蛋白表达增加,3-AB预处理可以明显降低AngⅡ诱导的心肌细胞内异常基因表达增加,提示PARPl参与了心室重构的发生发展过程.     

2-羟基苄胺改善衰老相关动脉粥样硬化的机制研究

目的探索不同浓度2-羟基苄胺(2-HOBA)对动脉粥样硬化和血管平滑肌细胞衰老的影响及相关作用机制。方法使用载脂蛋白E基因缺陷(ApoE-/-)小鼠14只建立动脉粥样硬化模型, ApoE-/-小鼠数字抽签法分为2组(每组7只):高脂饮食(HD)组和高脂饮食加2-HOBA(1 mg/ml)饮水喂药(HD+HOBA)组。脉搏波传导速度检测血管硬度, 同时使用跑步机检测运动耐力, 油红O染色法检测动脉粥样斑块的大小及数量, Masson染色检测斑块内部胶原纤维、弹力纤维的形态, 斑块核心坏死区域的大小及纤维帽的厚度。小鼠平滑肌细胞分别使用不同浓度的2-HOBA(100 μmol/L、250 μmol/L和500 μmol/L)干预过氧化氢诱导的应激衰老模型, 衰老相关β-半乳糖苷酶染色检测细胞衰老程度, 应用实时荧光定量聚合酶链式反应(RT-qPCR)检测衰老相关分泌表型因子的mRNA表达水平, 同时使用免疫印迹法检测衰老相关信号蛋白表达水平。结果与高HD组小鼠比较, HD+HOBA组小鼠在2-HOBA的干预下主动脉粥样斑块面积与数量减小, 同时稳定粥样斑块。此外, 与HD组小鼠主动脉血管硬...     

血清SAM/SAH在Hcy引起动脉粥样硬化基因组DNA甲基化中的作用

目的探讨血清S-腺苷甲硫氨酸(SAM)/S-腺苷同型半胱氨酸(SAH)比值在同型半胱氨酸(Hcy)致载脂蛋白E基因敲除(Apo E―/―)小鼠血管动脉粥样硬化(As)B1重复序列DNA甲基化改变中的作用。方法 36只饲养4周龄Apo E―/―小鼠,随机分为三组:模型对照组、高蛋氨酸组、叶酸+Vit B12干预组,每组12只,分别给予不同饮食;另取健康4周龄雄鼠(SPF级C57BL/6J)12只作为正常对照组,饲以普通饮食。饲养15周后,HE染色观察血管内动脉斑块的形成,高效液相色谱检测血清中Hcy、SAM、SAH的水平改变,n MS-PCR检测各组小鼠动脉粥样硬化斑块中Bl重复序列DNA甲基化改变。结果高蛋氨酸组血清Hcy与正常对照组相比升高约2.39倍(P0.01),HE染色可见高蛋氨酸组中有动脉斑块形成;与正常对照组相比,模型对照组、高蛋氨酸组SAM/SAH增加了1.68倍和2.75倍(P0.01);高蛋氨酸组B1重复序列DNA甲基化水平降低11.8%(P0.05),且与SAM/SAH比值呈明显负相关(r=-0.3638,P=0.0210)。结论 ApoE―/―小鼠中B1重复序列发生DNA低甲基化改变,且与SAM/SAH呈负相关,提示血清SAM/SAH可作为一个判断血管As的生物学指标。     

脑梗死认知障碍与颈动脉粥样硬化及尿酸、同型半胱氨酸的相关性

目的 研究脑梗死认知障碍与颈动脉粥样硬化、尿酸(UA)、同型半胱氨酸(Hcy)水平的相关性。方法 本研究以我院2021年1月至2022年1月收治的脑梗死患者75例为研究对象,按照认知功能水平分为认知功能障碍组(n=45)与认知功能正常组(n=30),分别设置为观察组与对照组,比较两组患者的粥样硬化指标、尿酸及同型半胱氨酸表达水平差异。结果 观察组患者颈动脉内膜中层厚度(IMT)为(1.69±0.21)mm、斑块面积为(38.59±7.97)mm²,对照组IMT为(1.43±0.14)mm、斑块面积为(11.49±2.52)mm²,两项数据观察组均大于对照组(P<0.05)。观察组患者颈动脉狭窄程度百分比为(73.39±12.54)%,显著高于对照组的(38.64±8.41)%,狭窄程度较对照组更严重(P<0.05);观察组尿酸、同型半胱氨酸表达水平分别为(458.59±53.49)μmol/L、(26.18±7.01)μmol/L,均显著高于对照组的(375.43±49.85)μmol/L、(17.24±4.17)μmol/L,差...     

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。     

多聚二磷酸腺苷核糖合成酶抑制剂对血管紧张素Ⅱ诱导心脏成纤维细胞基质金属蛋白酶表达的影响

目的:观察多聚二磷酸腺苷核糖合成酶(PARP)抑制剂对血管紧张素Ⅱ(AngⅡ)刺激的乳鼠心脏成纤维细胞基质金属蛋白酶-2(MMP-2)、基质金属蛋白酶-9(MMP-9)和金属蛋白酶组织抑制剂-1(TIMP-1)基因转录的影响.方法:新生SD大鼠心脏成纤维细胞原代培养,传代.用PARP抑制剂--3-氨基苯甲酰胺(3-AB)预处理细胞,观察3-AB对AngⅡ诱导心脏成纤维细胞MMP-2、MMP-9及TIMP-1基因表达的影响.结果:AngⅡ刺激心脏成纤维细胞MMP-2、MMP-9及TIMP-1基因表达明显增加,成纤维细胞内PARP活性及PARP1的表达显著增强.使用3-AB抑制PARP1的活性及表达,可以明显降低AngⅡ诱导的心脏成纤维细胞MMP-2、MMP-9及TIMP-1基因表达的增加.结论:PARP在AngⅡ诱导的心脏重构过程中发挥了重要的调控作用.     

动脉粥样硬化斑块内FIZZ1表达促进平滑肌细胞清道夫受体-A上调

目的探讨ApoE基因敲除鼠动脉粥样硬化斑块内FIZZ1表达情况及其对平滑肌细胞清道夫受体A(SR-A)表达的影响.方法C57BL/6J ApoE基因敲除鼠及C57BL/6J野生型小鼠各9只,分别喂养高脂饲料及普通饲料,24周后处死小鼠,石蜡包埋血管后做连续切片,行HE染色及FIZZ1免疫组化.用氧化型低密度脂蛋白(ox-LDL)以及终浓度分别为3×10-6mmol/L、9×10-6mmol/L、2.7×10-5mmol/L的FIZZ1刺激培养的平滑肌细胞,激光共聚焦显微镜确认SR-A表达后,流式细胞术检测FIZZ1对ox-LDL诱导的平滑肌细胞SR-A表达的影响.结果ApoE基因敲除鼠高脂饲养24周后,主动脉根部明显形成动脉粥样硬化,可见FIZZ1在动脉粥样硬化斑块内明显表达,同龄野生型C57BL/6J鼠正常血管壁内,未见FIZZ1表达,重组FIZZ1能明显促进ox-LDL诱导的平滑肌细胞SR-A表达(与对照组比较,P<0.01).结论C57BL/6J野生型小鼠正常血管不表达FIZZ1,C57BL/6JApoE基因敲除鼠动脉粥样斑块表达FIZZ1,FIZZ1促进ox-LDL诱导的平滑肌细胞SR-A表达,提示FIZZ1可能在ApoE基因敲除鼠动脉粥样硬化进展中起一定的促进作用.     

Poly (ADP-ribose) Polymerase Inhibition Improves Endothelial Dysfunction Induced by Hyperhomocysteinemia in Rats

Introduction  We investigated the possible protective effect of poly (ADP-ribose) polymerase (PARP) inhibition in preventing endothelial dysfunction induced by hyperhomocysteinemia (Hhcy). Methods  Sprague–Dawley rats were divided into Hhcy group, Hhcy + 3-aminobenzamide(3-AB) group, control group and control + 3-AB group. A high-methionine diet was given to induce hyperhomocysteinemia. In Hhcy + 3-AB and control + 3-AB groups, rats were injected intraperitoneally with 3-AB (inhibitor of PARP). After 45 days, ultrastructural changes of aortas were observed by transmission electron microscope. Vascular reactivity of thoracic aortic rings was measured in organ chambers. PARP activity was detected. The levels of plasma total homocysteine, nitrite/nitrate, endothelin (ET)-1 and malondialdehyde were assayed. Results  Rats in Hhcy group developed severe hyperhomocysteinemia and significant loss of endothelial function as measured by both vascular rings and levels of nitrite/nitrate and ET-1. Malondialdehyde levels increased significantly in Hhcy rats compared with control rats. 3-AB improved Ach-induced, NO-mediated vascular relaxation and stabilized the level of nitrite/nitrate and ET-1. Obvious improvement of ultrastructure can be observed in Hhcy + 3-AB group. Conclusions  These results suggest that pharmacological inhibition of PARP prevents the development of endothelial dysfunction in rats with hyperhomocysteinemia which may represent a novel approach to improve vascular dysfunction associated with hyperhomocysteinemia. Xian Yu and Xiang Cheng contribute to the work equally. This work was supported by grants from Chenguang plan of Wuhan in China (NO:[2006] 40) and National Basic Research Program of China (973 Program): 2007CB512000;2007CB512005.     

Differential effects of PARP inhibition on vascular cell survival and ACAT-1 expression favouring atherosclerotic plaque stability

AIMS: The aim of this study was to take a combination of animal and cell culture approaches to examine the individual responses of vascular cells to varying inflammatory factors in order to gain insights on the mechanism(s) by which poly(ADP-ribose) polymerase (PARP) inhibition promotes factors of plaque stability. METHODS AND RESULTS: Apolipoprotein (ApoE(-/-)) mice fed a high-fat diet were used as a model of atherosclerosis. Primary endothelial cells, smooth muscle cells (SMCs), and ex-vivo generated foam cells (FCs) were used in our in vitro studies. PARP inhibition significantly decreased the markers of oxidative stress and caspase-3 activation and increased smooth muscle actin within plaques from ApoE(-/-) mice fed a high-fat diet. PARP inhibition protected against apoptosis and/or necrosis in SMCs and endothelial cells in response to H(2)O(2) or tumour necrosis factor (TNF). Remarkably, PARP inhibition in FCs resulted in significant sensitization to 7-ketocholesterol (7-KC) by increasing cellular-toxic-free cholesterol, potentially through a down-regulation of acyl-CoA:cholesterol acyltransferase-1 (ACAT-1) expression. 7-KC induced necrosis exclusively in endothelial cells, which was, surprisingly, unaffected by PARP inhibition indicating that PARP inhibition does not prevent all forms of necrotic cell death. In SMCs, PARP-1 inhibition by gene deletion conferred protection against 7-KC or TNF, potentially by reducing caspase-3-like activation, preventing induction of c-Jun N-terminal protein kinase phosphorylation, and inducing extracellular signal-regulated kinase phosphorylation independently of PARP classical enzymatic activity. CONCLUSIONS: These data present PARP-1 as an important player in the death of cells constituting atherosclerotic plaques contributing to plaque dynamics. PARP inhibition may be a protective, a neutral, or a sensitizing factor. Additionally, PARP-1 may be a novel factor that can alter lipid metabolism. These novel functions of PARP not only challenge the current understanding of the role of the enzyme in cell death but also provide insights on the intricate contribution of PARP in cellular responses to predominant inflammatory factors within atherosclerotic plaques, presenting additional evidence for the viability of PARP inhibition as a therapeutic strategy for atherosclerosis.     

凝血因子V莱顿突变对载脂蛋白E基因敲除小鼠动脉粥样硬化的影响

目的 评价凝血因子V莱顿突变(FvL)对动脉粥样硬化的影响.方法 建立FvL与载脂蛋白E(ApoE)基因复合突变小鼠,并分析其动脉粥样硬化形成和纤维蛋白沉积情况.结果 小鼠52周龄时,FvL纯合子ApoE-/-(FvQ/Q APOE-/-)小鼠动脉粥样硬化范围明显大于野生型ApoE-/-(Fv+/+ApoE-/-),小鼠,FvQ/Q ApoE-/-比Fv+/+ApoE-/-为(5.0±1.1)%比(2.2±0.4)%,P＜0.005;FvL杂合子ApoE-/-(FvQ/+ApoE-/-)小鼠动脉粥样硬化范围位于FvQ/Q ApoE-/-小鼠和Fv+/+ApoE-/-小鼠之间,与两者的差异均无统计学意义,FvQ/+ApoE-/-比FvQ/QApoE-/-为(2.9±0.6)%比(5.0.±1.1)%,P＞0.05,FvQ/+ApoE-/-比Fv+/+ApoE-/-为(2.9±0.6)%比(2.2±0.4)%,P＞0.05.FvQ/Q ApoE-/-小鼠动脉粥样硬化斑块内的纤维蛋白沉积同样明显高于Fv+/+ApoE-/-小鼠,FvQ/Q ApoE-/-比Fv+/+ApoE-/-为(3.4±0.5)%比(1.8±0.4)%,P＜0.05.结论 FvL纯合子明显增加ApoE-/-小鼠动脉粥样硬化程度及动脉粥样硬化斑块内的纤维蛋白沉积,提示FvL突变可能是重要的促进动脉粥样硬化形成的因素,临床上患者出现严重的动脉粥样硬化可能合并FvL遗传基因缺陷.     

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.     

Reduced atherosclerotic plaque but enhanced aneurysm formation in mice with inactivation of the tissue inhibitor of metalloproteinase-1 (TIMP-1) gene

Development and progression of atherosclerotic lesions and aneurysm formation were investigated in mice with single or combined deficiency of apolipoprotein E (ApoE) and tissue inhibitor of metalloproteinase-1 (TIMP-1) kept on a cholesterol-rich diet for 30 weeks. Atherosclerotic lesions throughout the thoracic aorta were significantly (P<0.001) larger in mice wild-type for TIMP-1 (ApoE-/-:TIMP-1+/+) than in mice deficient in TIMP-1 (ApoE-/-:TIMP-1-/-). Aneurysms in the thoracic and abdominal aortas were less frequent in ApoE-/-:TIMP-1+/+ mice than in ApoE-/-:TIMP-1-/- mice (11+/-3.0 versus 23+/-5.1 aneurysms per 100 sections analyzed, mean+/-SD, P<0.001). Immunocytochemistry revealed enhanced accumulation of Oil red O-stained lipids, colocalizing with macrophages in atherosclerotic lesions of ApoE-/-:TIMP-1-/- mice (P<0.05). In situ zymography using a casein substrate showed enhanced lysis in plaques of ApoE-/-:TIMP-1-/- mice as compared with ApoE-/-:TIMP-1+/+ mice (P<0.01). MMP activity was most pronounced at sites where degradation of the elastic lamina occurred. These data suggest that enhanced MMP activity, as a result of TIMP-1 deficiency, contributes to a reduction of atherosclerotic plaque size but promotes aneurysm formation.     

载脂蛋白E基因敲除小鼠动脉粥样硬化早期血管外膜血管细胞黏附分子1和细胞间黏附分子1的表达

目的探讨血管外膜血管细胞黏附分子1和细胞间黏附分子1在动脉粥样硬化病灶形成及发展中的作用。方法 6周龄载脂蛋白E基因敲除小鼠和野生型C57BL/6小鼠,高脂饮食喂养2、4和8周,选取升主动脉制备连续切片,部分切片行Movat染色,观察组织形态学变化并测量外膜厚度的变化;部分切片用免疫组织化学法观察不同阶段血管外膜及内膜血管细胞黏附分子1和细胞间黏附分子1表达的动态变化。结果 6周龄载脂蛋白E基因敲除小鼠和各个时间点的C57BL/6小鼠均未观察到内膜损伤的任何迹象,主动脉外膜厚度亦无显著变化,外膜均无血管细胞黏附分子1的表达;高脂喂养2周后,载脂蛋白E基因敲除小鼠血管外膜厚度增加,但在内膜仍无肉眼可见病灶,此时外膜血管细胞黏附分子1呈现弱阳性表达;高脂喂养4周和8周后,载脂蛋白E基因敲除小鼠血管外膜厚度逐渐增加,内膜出现泡沫细胞,纤维斑块,外膜及内膜损伤处血管细胞黏附分子1表达增强。载脂蛋白E基因敲除小鼠随着高脂喂养时间延长,主动脉外膜及内膜细胞间黏附分子1的表达也增加,但C57BL/6小鼠血管外膜细胞间黏附分子1表达量少且稳定,各时间点之间无明显差异。结论载脂蛋白E基因敲除小鼠随着高脂喂养时间延长血管外膜血管细胞黏附分子1和细胞间黏附分子1的表达增加。     

Increased hypercholesterolemia and atherosclerosis in mice lacking both ApoE and leptin receptor

Diabetes mellitus is one of the major risk factors associated with atherosclerosis and coronary heart disease but the mechanistic links between the disease and atherosclerosis are not well understood. In this study, we investigated the effect of the deletion of the long-form leptin receptor on the progression of atherosclerosis in ApoE-/- mouse. ApoE-/-;db/db double knockout mice as well as ApoE-/-;db/+ and ApoE-/- littermates were generated by crossing ApoE-/- and db/+ mice. On a regular chow diet, ApoE-/-;db/db mice at 20 weeks of age exhibited features typical of type 2 diabetes: obesity, hyperglycemia, hyperinsulinemia and dyslipidemia and had significantly accelerated atherosclerosis compared with their age-matched ApoE-/- littermates as assessed by either the percentage of the aorta bearing lesion (5.3+/-0.9% for ApoE-/-;db/db versus 1.5+/-0.5% for ApoE-/-) or by aortic lipid content ( approximately 1.5-2-fold increase in free cholesterol and approximately 3-4-fold increase in cholesteryl ester). The atherosclerosis in these ApoE-/-;db/db mice was further accelerated by feeding mice with a Western diet and markedly inhibited by fenofibrate with a 2.5- and 5.3-fold reduction of the lesion in male and female mice, respectively. The results from this study demonstrate that type 2 diabetes can accelerate atherogenesis in mice. This mouse model may provide insight into the mechanistic link between type 2 diabetes and atherosclerosis as well as serve as a valuable tool for evaluating therapeutics.