蜂胶总黄酮对异丙肾上腺素致病理性心肌肥厚小鼠心功能的影响

目的探讨蜂胶总黄酮(TFP)对异丙肾上腺素(ISO)诱导的病理性心肌肥厚(PCH)小鼠心功能的影响。方法 8周龄雄性小鼠20只,适应性饲养1 w,随机分为对照组、ISO组、TFP组及ISO+TFP组。预先口服TFP(25 mg·kg-1·d-1)7 d之后持续给予ISO(25 mg·kg-1·d-1)7 d制备小鼠PCH模型。试验结束后24 h进行超声心动图检测,计算心脏重量/体重(HW/BW)比值,检测心房钠尿肽(ANP)的mRNA和蛋白表达水平。结果与对照组比较,ISO组小鼠收缩期左室内径(LVIDs)、舒张期左室内径(LVIDd)及左室收缩末期容积(LVVs)均明显升高,而射血分数(EF)、缩短分数(FS)明显降低,HW/BW及ANP蛋白、mRNA水平亦明显升高(P0.05);与ISO组比较,TFP+ISO组LVIDs、LVIDd及LVVs均明显降低,而EF、FS明显升高(P0.05),HW/BW及ANP蛋白、mRNA水平亦明显降低(P0.05)。结论 TFP可对抗ISO诱导的小鼠PCH,并对心功能损伤具有保护作用。     

MCP-1与CVB3相互作用参与病毒性心肌炎的发生

目的　研究单核细胞趋化蛋白 - 1(MCP- 1)在 B3型柯萨奇病毒 (CVB3)诱导病毒性心肌炎 (VMC)发病中的作用。方法　构建小鼠 MCP- 1真核表达质粒 p VM。 CVB3腹腔注射雄性 BAL B/c小鼠 ,随机分四组 :单独 CVB3感染 VMC组 (A组 )、10 μg过表达 MCP- 1组 (B组 )、4 0 μg过表达 MCP- 1组 (C)和空质粒对照组 (D组 )。并设未感染生理盐水对照组 (E组 )和未感染过表达组 (F组 )。比较各组小鼠心脏重量和体重的比值 (HW/BW)、心肌组织病理学积分 (PS)、心肌组织病毒载量、血清 CK- MB水平。结果　与 E组相比 ,A组的 HW/BW、PS、血清 CK- MB和心肌组织病毒载量均有明显改变。表明 CVB3感染后小鼠出现一系列的体征改变。与 A组相比 B组的 HW/BW、PS、血清 CK- MB和心肌组织病毒载量均未呈明显改变。但 C组 CVB3载量明显降低 (P<0 .0 5 ) ,血清 CK- MB水平升高 (P<0 .0 1) ,而 HW虽然升高(P<0 .0 5 ) ,但是 HW/BW未呈明显的改变 (P>0 .0 5 ) ,PS升高 (P<0 .0 5 )。 D组与 A组相比 ,CVB3载量、血清 CK-MB水平、HW/BW和 PS均未呈明显的改变 (P>0 .0 5 )。 F组的 HW/BW和血清 CK- MB水平与 E组相比未呈现显著性差异 ,而 PS升高 ,但低于 A组 (P<0 .0 1)。结论　单独在心肌组织过表达 MCP- 1仅引起心肌组织学改变 ,不能     

辛伐他汀抑制RhoA蛋白表达、Rho GTPase活性表达逆转兔心室重构

目的:在兔前后负荷增加心力衰竭模型,观察辛伐他订对心肌肥厚、心功能的影响,探讨辛伐他订抑制心肌肥厚、改善心功能的机制。方法:24只新西兰白兔分为4组,一组假手术组,为健康对照。2、3、4组通过破坏主动脉瓣和缩窄腹主动脉,增加左心室前、后负荷,建立慢性心力衰竭模型;2组:心力衰竭对照组;3组:心力衰竭早干预组,术后每天给与辛伐他汀5 mg/kg灌胃,观察8周;4组:心力衰竭晚干预组:手术4周后每天给与辛伐他汀5 mg/kg灌胃,观察4周。各组术后及观察结束时行超声心动图检查;Western blot分析心肌细白膜RhoA蛋白表达,[γ-32P]GTP结合分析检测Rho GTPase活性。结果:早干预组及晚干预组室间隔厚度(IVST)、左心室舒张期内径(LVIDd)、左心室后壁厚度(LVPwd)、左心室收缩期内径(LVIDs)、心脏质量(HW)、左心室质量(LVW)、心脏/体质量比(HW/BW radio)、显著低于心力衰竭对照组,射血分数(EF)、左室长轴缩短率(FS)显著高于心衰对照组。早干预组左心室/体质量比(LVW/BW radio)显著低于心力衰竭对照组。心力衰竭组心肌细胞膜RhoA蛋白表达、Rho GTPase活性明显高于健康对照组,辛伐他汀早干预组及晚干预组心肌细胞膜RhoA蛋白表达及Rho GTPase活性显著低于心力衰竭对照组。结论:辛伐他订通过抑制RhoA蛋白由胞浆转至新胞膜、抑制Rho GTPase活性而抑制心肌肥厚,改善心功能。     

稳心颗粒对大鼠心肌肥厚的影响及作用机制研究

目的 观察稳心颗粒对大鼠心肌肥厚的影响,并探讨其相关机制.方法 将30只大鼠随机分为对照组、异丙肾上腺素(ISO)组和ISO +稳心颗粒组,每组10只.检测心脏质量/体质量(HW/BW)及左室质量/体质量(LVW/BW),观察心肌细胞β-连环蛋白(β-catenin)及c-myc蛋白的变化被观察.结果 与对照组比较,ISO组大鼠HW/BW和 LVW/BW明显增加(P<0.05),β-catenin及c-myc蛋白表达明显增加(P<0.05);与ISO组比较,ISO+稳心颗粒组大鼠HW/BW和 LVW/BW明显降低(P<0.05),β-catenin及c-myc蛋白表达明显减少(P<0.05).结论 稳心颗粒可明显减轻大鼠心肌肥厚,这可能与β-catenin及c-myc蛋白表达的变化有关.     

辛伐他汀对心肌肥厚的防治作用及其与JAK激酶/信号转录活化因子通路关系的实验研究

目的 探讨辛伐他汀对心肌肥厚的防治作用及其与JAK激酶/信号转录活化因子(JAK/STAT)信号转导通路的关系.方法 采用心肌营养素-1(CT-1)诱导新生大鼠心肌细胞肥大模型和腹主动脉缩窄术建立心肌肥厚动物模型.通过改良Lowry法测定心肌细胞总蛋白含量.相差显微镜测定心肌细胞表面积.逆转录聚合酶链法检测血管紧张素原(AGT)mRNA及c-fos mRNA表达.尾动脉无创测量大鼠收缩压的变化.称量心脏重量/体重(HW/BW)、左心室重量/体重(LVW/BW)比值.Western blot方法 检测磷酸化-JAK激酶(p-JAK2)和磷酸化-信号转录活化因子(p-STAT3)蛋白表达.结果 (1)辛伐他汀能明显抑制CT-1诱导的心肌细胞总蛋白含量增加(9.20 μg/105cell降至6.66 μg/105cell)和心肌细胞表面积增加(1741.63 μm2降至826.76 μm2).(2)辛伐他汀、JAK激酶抑制剂AG490均可明显抑制CT-1诱导的心肌细胞p-JAK2和p-STAT3蛋白表达以及AGT mRNA和c-fos mRNA表达(P<0.01).(3)辛伐他汀可明显降低腹主动脉缩窄大鼠的收缩压[186.64 mm Hg(1 mm Hg=0.133 kPa)降至132.56 mm Hg]、HW/BW比值(3.87 mg/g降至3.29 mg/g)、LVW/BW比值(2.74 mg/g降至2.32 mg/g).(4)辛伐他汀可明显抑制腹主动脉缩窄大鼠心肌p-JAK2和p-STAT3蛋白表达(P<0.01).结论 辛伐他汀对CT-1诱导的大鼠心肌细胞肥大和腹主动脉缩窄所致心肌肥厚均具有明显的防治作用,其作用机制可能与其抑制JAK/STAT信号通路的激活,减少肥厚相关基因AGT mRNA、c-fos mRNA表达有关.     

老龄载脂蛋白E基因敲除小鼠血脂及病理组织学观察

目的:观察用普食喂养而非以往研究中的高脂饮食喂养的载脂蛋白E基因敲除小鼠(Apo E-/-)的血脂及病理组织学变化特点。方法:各选取20只8周龄雄性小鼠和同龄同性C57BL/6J小鼠为对照,普食喂养6~8个月,测定血清中总胆固醇(TC)、三酰甘油(TG)、低密度脂蛋白(LDL)和高密度脂蛋白(HDL)的含量。常规制备主动脉的病理切片,进行HE染色,观察病理学变化。结果:Apo E-/-小鼠血清中TC、TG、LDL含量明显高于对照组(P0.05),且Apo E-/-小鼠主动脉根部病理切片明显脂质斑块形成。结论:普食喂养8月龄Apo E-/-小鼠是研究动脉粥样硬化(AS)的理想动物模型,为AS性心血管疾病研究者提供了参考资料。     

MST1启动子区DNA低甲基化在ApoE－/－小鼠肾损伤中的作用

目的探讨哺乳动物不育系20样激酶1(MST1)及其DNA甲基化在载脂蛋白E基因敲除(Apo E-/-)小鼠肾损伤中的作用及意义。方法实验动物分为2组:(1)Apo E-/-组(n=10):雄性Apo E-/-鼠饲以高蛋氨酸饮食;(2)对照组(n=10):雄性C57BL/6J鼠饲以高蛋氨酸饮食。喂养14周后,全自动生物化学分析仪测定小鼠血清肌酐和尿素氮水平;PAS染色及透射电子显微镜观察小鼠肾脏组织损伤情况;实时定量PCR及Western blot分别检测小鼠肾脏中MST1 mRNA和蛋白表达水平。巢式甲基化特异性PCR(n MS-PCR)检测小鼠肾脏MST1 DNA甲基化水平。结果与对照组比较,Apo E-/-组血清肌酐和尿素氮分别升高了1.1倍和1.6倍(P0.01);PAS染色和透射电镜结果显示,Apo E-/-组较对照组肾脏明显损伤;Apo E-/-小鼠肾脏MST1表达分别与血清肌酐和尿素氮水平呈正相关(R2=0.7571,P=0.0012;R2=0.7342,P=0.0015);n MS-PCR结果显示,Apo E-/-组肾脏中MST1 DNA甲基化水平较对照组显著降低(P0.01)。结论 MST1表达上调可能在Apo E-/-小鼠肾损伤中发挥重要作用,而MST1启动子区DNA低甲基化改变可能是MST1表达上调的重要机制。     

依普利酮对鸟苷酸环化酶偶联受体A基因敲除小鼠心肌纤维化的作用

背景鸟苷酸环化酶偶联受体A(GC-A)为心钠素(ANP)和脑钠素(BNP)的共有受体,ANP和BNP通过与GC-A结合引起利尿、利钠及扩血管作用,并可抑制肾素和醛固酮分泌,GC-A基因敲除小鼠表现为高血压、心室肥厚和心肌纤维化。目的探讨高选择性醛固酮受体拮抗剂依普利酮对鸟苷酸环化酶偶联受体A基因敲除(GC-A-KO)小鼠心肌纤维化的作用。方法12周龄GC-A-KO雄性小鼠21只分成对照组(n=7)、依普利酮组[e-KO组,n=7,100mg/(kg.d)×4周]和肼苯哒嗪组[h-KO组,n=7,10mg/(kg·d)×4周],另有野生型(WT)小鼠7只用于测定血压、心率及组织学分析。小鼠于16周龄时处死,计算心脏与体质量比值(HW/BW);利用图像分析系统测量心肌胶原容积分数(CVF)和心肌血管周围胶原面积和管腔面积之比(PVCA);半定量RT-PCR法检测心室胶原纤维Ⅰ和胶原纤维ⅢmRNA在心肌组织表达。结果依普利酮组和肼苯哒嗪组收缩压较对照组明显降低[分别为(103.2±4.2)和(99.6±6.2)vs(130.6±9.2)mm Hg,P均<0.01];依普利酮组的HW/BW为(4.7±0.3)mg/g低于对照组(5.9±0.5)mg/g(P<0.05),而肼苯哒嗪组HW/BW为(6.8±0.3)mg/g高于对照组(P<0.05);与对照组比较,依普利酮组的CVF、PVCA及胶原纤维Ⅰ和胶原纤维ⅢmRNA的表达下降(P<0.01、0.05和0.05),纤维化程度减轻;肼苯哒嗪组尽管血压下降程度与依普利酮组相似,但CVF、PVCA及胶原纤维Ⅰ和胶原纤维Ⅲ mRNA的表达均增加(P均<0.05),纤维化程度加重。结论依普利酮可独立于血压改善心肌纤维化和心室重构。     

辛伐他汀对高糖损伤乳鼠心肌细胞NADPH氧化酶亚基基因表达的影响

取原代培养的SD雄性乳鼠心肌细胞在高糖刺激下加入10-7、10-6和10-5mol/L辛伐他汀作用72 h.结果显示,与对照组比较,高糖组心肌细胞活力明显降低(P＜0.01),乳酸脱氢酶(LDH)活性显著增加(P＜0.01),NADPH氧化酶亚基p22phox、p47phox mRNA表达和活性氧簇(ROS)水平明显增高(均P＜0.05);与高糖组比较,辛伐他汀各组心肌细胞活力明显增加(P＜0.05),LDH活性显著降低(P＜0.05),p22phox、p47phox mRNA表达和ROS水平明显降低,且辛伐他汀浓度对心肌细胞活力的影响呈剂量依赖效应.这些结果提示辛伐他汀能够抑制NADPH氧化酶亚基的基因表达,减轻高糖引起的心肌损伤.     

葡萄籽原花青素对自发性高血压大鼠左室重塑和氧化应激的影响

目的观察葡萄籽原花青素(GSP)对自发性高血压大鼠(SHR)左室重塑和氧化应激的影响。方法 8周龄雄性SHR 24只随机分成4组(每组6只):SHR组、GSP低剂量组(50 mg·kg~(-1)·d~(-1))和GSP高剂量组(200 mg·kg~(-1)·d~(-1))及卡托普利组(30 mg·kg~(-1)·d~(-1))。6只同龄雄性Wistar-Kyoto大鼠设为对照组。治疗8 w后,测定尾动脉收缩压(SBP)、全心重量指数(HW/BW)和左心室重量指数(LVW/BW);生化法检测左室心肌组织中丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性和抑制羟自由基(OH·)能力;HE和Masson染色下观察心肌细胞形态和胶原分布,并测定心肌细胞横截面积(CSA)与心肌胶原容积分数(CVF);Western印迹法检测左室心肌组织p47phox蛋白表达。结果 GSP能显著降低SHR的SBP(P0.01),改善左室重塑参数、减少心肌组织MDA含量及p47phox蛋白表达(P0.05),提高SOD活性及抑制OH·能力(P0.05),GSP高剂量组作用尤为显著(P0.01)。结论 GSP对SHR左室重塑有减轻作用,可能与降低SBP、抑制氧化应激及下调p47phox蛋白表达有关。     

达肝素对载脂蛋白E基因缺陷小鼠肾动脉粥样硬化病变的影响

目的在动脉粥样硬化模型鼠中,观察达肝素对肾动脉粥样硬化病变进展及对植物血凝素样氧化型低密度脂蛋白受体1(LOX-1)和血管内皮生长因子(VEGF)的表达影响,探讨达肝素可能的抗动脉粥样硬化机制。方法以6周龄雄性C57BL/6J小鼠24只为对照,随机分为普通饲料组及高脂饲料组。雄性6周龄载脂蛋白E基因缺陷(Apo E-/-)小鼠36只,均予高脂饲料喂养至12周龄,随机分为模型组、低剂量肝素组[达肝素钠100 IU/(kg.d)]、高剂量肝素组[达肝素钠200 IU/(kg.d)],皮下注射连续4周(16周龄)后各组随机取6只处死。分离肾动脉,制成石蜡切片行HE及免疫组织化学染色,观察斑块情况及LOX-1蛋白的表达。用RT-PCR方法,检测肾动脉LOX-1 mRNA及VEGF mRNA的表达。用Western Blot分析法,检测肾动脉中LOX-1蛋白的表达。剩余小鼠继续原方案喂养4周(20周龄)后处死,肾动脉石蜡切片行HE染色,观察斑块情况。结果 Apo E-/-模型组在16周龄时出现轻度肾动脉粥样硬化。低剂量及高剂量达肝素均抑制肾动脉粥样硬化的形成(P<0.05)。Apo E-/-模型组LOX-1 mRNA、VEGF mRNA及LOX-1蛋白的表达水平较C57BL/6J普通饲料组的表达水平明显升高(P<0.05)。低剂量及高剂量达肝素治疗后,LOX-1 mRNA、VEGF mRNA及LOX-1蛋白的表达水平表达较模型组明显下降(P<0.05)。结论达肝素钠可能通过抑制LOX-1蛋白及VEGF表达的途径,抑制肾动脉粥样硬化的进展。     

丹参多酚酸盐对ApoE基因敲除小鼠血清脂质的干预作用

目的:观察中药丹参多酚酸盐对高脂饮食ApoE-/-小鼠脂质代谢的影响,探讨丹参多酚酸盐抗动脉粥样硬化作用机制。方法:将4周龄雄性C57BL/6J ApoE-/-小鼠喂食高脂饮食,随机分为4组。模型组腹腔注射生理盐水、丹参多酚酸盐干预分为低剂量组(60 mg/kg)、中剂量组(120 mg/kg)和高剂量组(240 mg/kg)腹腔注射丹参多酚酸,另设C57BL/6J野生型小鼠为对照组。于24周末时处死各组小鼠,留取血清,检测各组小鼠血清总胆固醇(TC)、三酰甘油(TG)、高密度脂蛋白胆固醇(HDL-C)和低密度脂蛋白胆固醇(LDL-C)水平。结果:与对照组比较,ApoE-/-鼠血清TC、LDL-C均明显升高(P<0.05),表明敲除ApoE基因能导致血脂代谢紊乱。应用丹参多酚酸盐后,各干预组TC、LDL-C水平均明显降低(P<0.05),但TG和HDL-C水平无明显改变,中、高剂量组尤为显著。结论:丹参多酚酸盐可降低ApoE-/-小鼠血清TC和LDL-C水平,可能是其抗动脉粥样硬化的作用机制之一。     

丙丁酚对动脉粥样硬化小鼠抗氧化作用的比较

目的观察丙丁酚对高脂高胆固醇饲养的C57BL/6J小鼠和载脂蛋白E基因缺陷(载脂蛋白E-/-)小鼠抗氧化作用的影响,比较丙丁酚对两种小鼠的作用差异。方法以高脂高胆固醇饲料饲喂小鼠,制作高脂血症模型。采用酶比色法及相关检测试剂盒分别测定小鼠血脂水平及与氧化应激相关的指标;采用双抗夹心ELISA法测定氧化型低密度脂蛋白的水平;采用改良的Eckerson方法测定对氧磷酶1的活性,采用逆转录聚合酶链式反应检测对氧磷酶1mRNA的表达。结果与两种小鼠各自的基础饲料组比较,高脂高胆固醇组血脂水平均有升高;与各自的高脂高胆固醇组比较,丙丁酚处理后,C57BL/6J小鼠血清的甘油三酯、总胆固醇、高密度脂蛋白胆固醇和低密度脂蛋白胆固醇水平分别降低了41.0%、43.6%、44.8%和41.3%(P<0.05),载脂蛋白E-/-小鼠血清的甘油三酯、总胆固醇、高密度脂蛋白胆固醇和低密度脂蛋白胆固醇水平,分别降低了36.2%、28.2%、31.3%、33.9%(P<0.05)。小鼠主动脉内膜的动脉粥样硬化病变与各自高脂高胆固醇组比较,C57BL/6J小鼠经丙丁酚处理后病变面积减少了61.1%,载脂蛋白E-/-小鼠经丙丁酚处理后病变面积减少了27.2%(P<0.05)。与各自基础饲料组比较,高脂血症小鼠丙二醛及氧化型低密度脂蛋白的水平增高,而总抗氧化能力和超氧化物歧化酶水平降低(P<0.05);与各自的高脂高胆固醇组比较,丙丁酚处理组小鼠的总抗氧化能力和超氧化物歧化酶水平上升,丙二醛及氧化型低密度脂蛋白的水平则降低(P<0.05)。两组小鼠高脂高胆固醇组血清对氧磷酶1的活性较基础饲料组均下降,经高脂饮食加丙丁酚处理后对氧磷酶1活性比单纯高脂饮食组有所增加;肝脏对氧磷酶1mRNA的表达在高脂高胆固醇组下调,而丙丁酚处理组则上调(P<0.05)。结论丙丁酚可以减轻高脂血症小鼠动脉粥样硬化病变,减轻高脂高胆固醇饮食诱导的氧化应激,而载脂蛋白E基因缺陷则一定程度减弱丙丁酚的上述作用。     

Simvastatin inhibits expression of tissue factor in advanced atherosclerotic lesions of apolipoprotein E deficient mice independently of lipid lowering: potential role of simvastatin-mediated inhibition of Egr-1 expression and activation

Recent studies suggest that the beneficial effects of 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitors (statins) in reducing cardiovascular events may in part, be independent of their capacity to lower plasma lipids. To test this hypothesis, simvastatin (50 mg/kg/d) was administered to 30-week-old apolipoprotein E deficient mice (apo E-/-) for 12, 18 and 24 weeks. In contrast to other experimental models and humans, simvastatin treatment increases plasma cholesterol levels in apo E-/- mice. Quantitative real-time polymerase chain reaction was used to quantify expression of tissue factor (TF) and monocyte chemoattractant protein-1 (MCP-1) in the aorta of each mouse. Expression of TF was reduced to 34, 24, and 13% of control levels at 12, 18 and 24 weeks, respectively, of simvastatin administration. Advanced lesions in the innominate arteries of the simvastatin treated mice had reduced levels of TF, fewer macrophages and reduced expression of early growth response-1 (Egr-1). In vitro studies in mouse macrophages demonstrated decreased lipopolysaccharide induced binding of nuclear proteins to the Egr-1 consensus DNA sequence following pretreatment with simvastatin. RNA levels for MCP-1 were reduced to 30% of control values following 24 weeks of simvastatin treatment. In conclusion, these data suggest that chronic administration of simvastatin to older apo E-/- mice can inhibit the expression of pro-thrombotic/pro-inflammatory genes within established atherosclerotic lesions via mechanisms that are independent of reductions in plasma lipids.     

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。     

Anti-atherosclerotic effect of simvastatin depends on the presence of apolipoprotein E

Low density lipoprotein receptor deficient (LDLR-KO) and apolipoprotein E deficient (apo E-KO) mice both develop hyperlipidemia and atherosclerosis by different mechanisms. The aim of the present study was to compare the effects of simvastatin on cholesterol levels, endothelial dysfunction, and aortic lesions in these two models of experimental atherosclerosis. Male LDLR-KO mice fed a high cholesterol (HC; 1%) diet developed atherosclerosis at 8 months of age with hypercholesterolemia. The addition of simvastatin (300 mg/kg daily) to the HC diet for 2 more months lowered total cholesterol levels by approximately 57% and reduced aortic plaque area by approximately 15% compared with the LDLR-KO mice continued on HC diet alone, P<0.05. Simvastatin treatment also improved acetylcholine (ACh)-induced endothelium-dependent vasorelaxation in isolated aortic rings, which was associated with an increase in NOS-3 expression by approximately 88% in the aorta measured by real time polymerase chain reaction (PCR), P<0.05. In contrast, in age-matched male apo E-KO mice fed a normal diet, the same treatment of simvastatin elevated serum total cholesterol by approximately 35%, increased aortic plaque area by approximately 15%, and had no effect on endothelial function. These results suggest that the therapeutic effects of simvastatin may depend on the presence of a functional apolipoprotein E.     

Hyperlipoproteinemia as a risk factor for ischemic heart disease

We analyzed serum lipoproteins and apolipoprotein E (apo E) from 199 patients in CCU, having ischemic heart disease, and from 211 healthy subjects. It was suggested that serum lipoprotein abnormalities, especially elevated low density lipoprotein (LDL) levels, are closely related to atherogenesis in relatively young patients and subjects with severe coronary lesions. The frequency of apo E-4 was higher and that of E-2 was lower in the CCU group than in the control group. Apo E mutants, E-7 (Glu244----Lys, Glu245----Lys) and E-5 (Glu3 (Glu3----Lys), were also frequent in the CCU group. Apo E isoproteins have higher pI in the order E-2, E-3, E-4, and we observed that LDL-cholesterol levels increased in the same order. The apo E mutants, E-5 and E-7, are also more basic than E-4. These findings suggest that basic apo Es were associated with the development of atherosclerosis. The prevalence of familial hypercholesterolemia (FH) in the CCU group was more than 10 times higher than the reported frequency of FH heterozygotes in normal population. The persistence of marked hypercholesterolemia from infancy probably makes FH patients susceptible to atherosclerosis. Based on the analysis of LDL-receptor protein synthesis, various types of mutations were observed even in phenotypically homozygous FH patients. FH homozygotes were divided into 2 groups, a receptor-negative group and a receptor-defective group. We found a great difference in the frequency of coronary heart disease depending on whether even a small number of receptors were present or not.     

载脂蛋白E基因敲除小鼠动脉粥样硬化斑块中血小板因子4和Toll样受体2的表达

目的观察高脂饲养的载脂蛋白E基因敲除小鼠动脉粥样硬化斑块表达Toll样受体2和血小板因子4的情况,探讨血小板因子4对内皮细胞Toll样受体2表达的影响。方法高脂饲料喂养载脂蛋白E基因敲除小鼠12周,建立动脉粥样硬化模型。安乐死处死动物,原位灌流固定,取主动脉于10%中性缓冲福尔马林中固定,石蜡包埋连续切片,HE染色观察动脉粥样硬化斑块形态,免疫组织化学检测斑块中Toll样受体2和血小板因子4的表达。结果载脂蛋白E基因敲除小鼠血脂水平明显增高,主动脉HE染色可见态动脉粥样硬化病变。在载脂蛋白E基因敲除小鼠主动脉富含脂质斑块中Toll样受体2表达上调,其中血管内皮细胞、巨噬细胞表达Toll样受体2明显增多。载脂蛋白E基因敲除小鼠主动脉斑块中也发现有血小板因子4表达,主要在内皮细胞和动脉粥样硬化斑块肩部。结论1.载脂蛋白E基因敲除小鼠粥样斑块中Toll样受体2表达上调,并且Toll样受体2主要表达在粥样斑块的内皮细胞和巨噬细胞上。2.载脂蛋白E基因敲除小鼠动脉粥样硬化斑块中可见血小板因子4表达。     

AMD3100促进载脂蛋白E~(-/-)小鼠动脉粥样硬化斑块形成

目的探讨AMD3100对载脂蛋白E-/-小鼠主动脉动脉粥样硬化斑块形成的影响及其可能机制。方法12只8周龄雄性载脂蛋白E-/-小鼠随机分为AMD3100组(2.5mg/kg,隔天注射)和对照组(PBS 0.1mL,隔天注射),高脂高胆固醇饲料喂养12周后,获取组织标本和骨髓细胞,石蜡切片HE染色检测小鼠主动脉根部动脉粥样硬化病变;通过计数典型内皮祖细胞克隆形成单位和观察次级集落单位的大小与细胞密度检测内皮祖细胞的克隆形成能力;逆转录聚合酶链反应和Western blotting检测内皮祖细胞CXCR4 mRNA和蛋白的表达。结果AMD3100组小鼠主动脉窦横切面粥样斑块面积与管腔面积之比与对照组比较增加了38.8%(37.2%±3.6%比26.8%±2.5%,P<0.05);AMD3100组小鼠骨髓源内皮祖细胞的克隆形成能力显著低于对照组(初级内皮祖细胞集落单位个数为9.67±2.16比21.83±2.64,次级内皮祖细胞集落单位个数为1.67±0.31比4.11±0.65,P<0.01);AMD3100组CXCR4 mRNA和蛋白的表达均显著低于对照组(P<0.01)。结论AMD3100促进载脂蛋白E-/-小鼠动脉粥样硬化斑块形成,可能与抑制骨髓源内皮祖细胞的克隆形成并下调CXCR4表达相关。     

The conformation of apolipoprotein E isoforms in phospholipid complexes and their interaction with human Hep G2 cells

The human hepatoma cell line, Hep G2, has been used to compare the metabolism by isolated liver cells of purified isoforms of human apolipoprotein E (apo E). Complexes of [125I]apo E-3/3, 2/2, 3/2 and 4/3 with dimyristoyl phosphatidylcholine (DMPC) were prepared by a detergent-dialysis method: discoidal, bilayer complexes with a stoichiometry of 125 +/- 15 mol DMPC/mol apo E resulted. The predominant phenotype apo E-3/3, and the phenotype apo E-2/2 characteristic of patients with Type III hyperlipoproteinemia, interact similarly with DMPC and adopt the same conformation with 60-70% alpha-helix, as monitored by circular dichroism spectroscopy. The uptake and degradation at 37 degrees C, and binding at 4 degrees C by Hep G2 cells, of [125I]apo E-3/3/DMPC and [125I]apo E-2/2/DMPC complexes were compared. Apo E-3/3 was degraded more rapidly than apo E-2/2 suggesting that the diminished catabolism of the latter phenotype by intact livers is due to lack of recognition by the hepatocytes. The observed degradation of apo E was 3-4 times greater than that which could be attributed to fluid phase endocytosis and low-affinity adsorptive endocytosis. The degradation of [125I]apo A-I by Hep G2 cells can be accounted for by the above endocytotic mechanisms. The distinction between apo E-3/3 and apo E-2/2 isoforms is attributed to the presence of a cell-surface receptor on Hep G2 cells which binds apo E-3/3 with a higher affinity than apo E-2/2.