血管紧张素-(1-7) 对高血压大鼠血管紧张素Ⅱ及其受体的影响

目的观察血管紧张素-(1-7)[Ang-(1-7)]对二肾一夹(2K1C)高血压大鼠血浆及肾组织血管紧张素Ⅱ及其受体的影响.方法采用微渗泵植入技术,建立Ang-(1-7)对高血压大鼠干预模型,放免法测定血浆及肾组织血管紧张素Ⅱ(AⅡ)浓度,RT-PCR检测肾组织内血管紧张素Ⅱ 1型受体(AT1)和2型受体(AT2)mRNA水平.结果 Ang-(1-7)减轻2K1C高血压大鼠肾脏病理损害,Ang-(1-7)对血浆及肾组织AⅡ浓度无显著影响,对肾组织内AT2受体表达无显著影响,减少肾组织内AT1受体表达.结论 Ang-(1-7) 对2K1C高血压大鼠肾损害具有保护作用,其机制之一是通过减少肾组织内AT1受体而实现.     

血管紧张素-(1-7)对乳鼠心肌细胞缺血再灌注损伤的影响

目的:探讨血管紧张素-(1-7)[Ang-(1-7)]对心肌细胞缺血再灌注损伤(I/R)的影响及其可能机制。方法:提取乳鼠原代细胞,按缺氧4 h后再灌注2 h的条件建立I/R模型。提前20 min加入10-8、10-7、10-6、10-5mmol/l的Ang-(1-7)作为预处理,并随机分为对照组、I/R组、Ang-(1-7)组、替米沙坦组、血管紧张素Ⅱ组、Ang-(1-7)+替米沙坦组及Ang-(1-7)+血管紧张素Ⅱ组,使用CCK-8法检测心肌细胞存活率。结果:10-5mmol/L浓度的Ang-(1-7)的预处理能让细胞存活率提高到77.65%。与I/R组相比,Ang-(1-7)组、Ang-(1-7)+替米沙坦组及Ang-(1-7)+血管紧张素Ⅱ组心肌细胞存活率均显著提高,但各组间均无明显差异。结论 :Ang-(1-7)减少心肌细胞在I/R中的损伤,但该保护机制与血管紧张素受体Ⅱ无关。     

血管紧张素-(1-7)对高血压大鼠内皮功能的影响

目的探讨血管紧张素(17)[Ang(17)]对高血压大鼠血管内皮功能的影响。方法采用腹主动脉缩窄术制成高血压大鼠模型,45只SD大鼠分为假手术组、模型对照组、Ang(17)治疗组[25μg/(kg·h),持续给药]。4周后检测动脉血压、血浆NO2-/NO3-、主动脉环对乙酰胆碱(Ach)的舒张反应及主动脉eNOS和iNOS的表达。结果与假手术组比较,模型对照组动脉血压及血浆NO2-/NO3-均明显增高,Ach诱导的主动脉环舒张反应下降,主动脉eNOS表达降低、iNOS表达增加。与模型对照组比较,Ang(17)治疗未改变动脉血压和血浆NO2-/NO3-水平,但改善了主动脉环对Ach的舒张反应,并改善了主动脉eNOS、iNOS的异常表达。结论Ang(17)可改善高血压大鼠的血管内皮功能。     

血管紧张素-(1-7)对肺动脉平滑肌细胞增殖的影响

目的探讨血管紧张素-（1—7）[ANG-（1—7）]对体外培养兔肺动脉平滑肌细胞增殖的影响。方法体外培养兔肺动脉平滑肌细胞，鉴定后传代培养，取4～7代细胞，应用不同浓度ANG-（1—7）干预，并与血管紧张素-Ⅱ（ANG—Ⅱ，浓度10^-6mol／L）、空白组对照。通过台盼蓝染色法细胞计数、四甲基偶氮唑蓝（MTT）比色法，确定肺动脉平滑肌细胞的生长趋势变化。结果10^-12～10^-10mol/L浓度ANG-（1—7）与相应对照组比较，细胞数、光吸收值（A值）变化不明显，无统计学意义，10^-9～10^-5mol／L浓度组，ANG-（1—7）＋ANG—Ⅱ（浓度均为10^-6）组与空白对照组比较，细胞数和A值均下降，差异有统计学意义，与血管紧张素-Ⅱ组比较差异也有统计学意义；10^-6、10^-5浓度组与ANG-（1—7）＋ANG—Ⅱ（浓度均为10^-6mol／L）组引起的变化差异不明显，无统计学意义。结论ANG-（1—7）呈剂量依赖性抑制胎牛血清诱导的兔肺动脉平滑肌细胞增殖，在浓度为10^-6时效果最明显，再增加浓度效果无明显增强，这种抑制作用与ANG-Ⅱ的存在无明显关系。     

肝纤维化形成过程中还原型烟酰胺腺嘌呤二核苷酸磷酸氧化酶4与血管紧张素Ⅱ/血管紧张素-(1-7)比值的动态变化

目的研究肝纤维化形成过程中还原型烟酰胺腺嘌呤二核苷酸磷酸氧化酶(NOX)4m RNA表达与血管紧张素(Ang)Ⅱ/Ang-(1-7)比值的动态变化及其相互间的关系,探讨其在肝纤维化发病中的意义。方法制备四氯化碳(CCl4)诱导的肝纤维化大鼠模型,共8周。肝组织行常规HE及Masson染色,观察病理改变;双抗体夹心ABC-ELISA法分别测定肝匀浆AngⅡ、Ang-(1-7)浓度,计算其比值;RT-PCR检测肝组织NOX4 m RNA的表达量,所有数据采用SPSS 17.0统计软件进行分析。结果随着肝纤维化的形成及加重,模型组大鼠2、4、6、8周NOX4 m RNA相对表达量分别为6.53±0.89、5.49±1.24、14.49±2.39、31.78±3.96,均较正常对照组(2.03±0.31)升高(均P<0.05);同时,模型组大鼠AngⅡ/Ang-(1-7)比值逐渐增大(依次为0.65±0.06、0.66±0.07、0.79±0.07、0.82±0.04),均较对照组(0.59±0.04)增大,差异有统计学意义(均P<0.05),NOX4与AngⅡ/Ang-(1-7)比值的变化呈正相关(r=0.901,P<0.05)。结论在肝纤维化形成过程中,NOX4的表达进行性升高,同时AngⅡ/Ang-(1-7)比值逐渐增大,提示上述变化可能参与了肝纤维化的发生。     

三七总皂苷对氧化型低密度脂蛋白诱导的人脐静脉内皮细胞血管细胞黏附分子1表达的影响

背景：氧化低密度脂蛋白能诱导血管内皮细胞活化和黏附分子表达,在动脉粥样硬化形成早期起重要作用。三七总皂苷在心血管系统方面具有保护血管内皮细胞、显著改善动脉粥样硬化病变程度的药理作用。目的：验证三七总皂苷对氧化型低密度脂蛋白损伤内皮细胞后血管细胞黏附分子1的表达及与人单核细胞黏附的影响。设计、时间及地点：体外实验,分组对照,于2007—03／2008—05在北京中医药大学东直门医院中医内科学教育部重点实验室完成。材料：原代人脐静脉内皮细胞为美国CascadeBiologics公司产品;三七总皂苷（血塞通冻干粉针）为黑龙江珍宝岛制药有限公司产品,成分为三七总皂苷,批号：20040207。方法：以培养原代人脐静脉内皮细胞作为靶细胞,用氧化型低密度脂蛋白造成人脐静脉内皮细胞损伤模型。将培养的人脐静脉内皮细胞分为5组：氧化型低密度脂蛋白组（100mg／L）、氧化型低密度脂蛋白＋三七总皂苷组（终浓度分别为200,100,50mg／L）、正常对照组。主要观察指标：光镜下观察细胞形态变化,四甲基偶氮唑盐法检测细胞活性;采用蛋白定量法检测人脐静脉内皮细胞与单核细胞的黏附率;用流式细胞仪测定人脐静脉内皮细胞的血管细胞黏附分子1的蛋白表达。结果：氧化型低密度脂蛋白作用人脐静脉内皮细胞后12,24．h时,人脐静脉内皮细胞损伤明显,细胞活性显著降低,人单核细胞与人脐静脉内皮细胞的黏附率显著升高,人脐静脉内皮细胞的血管细胞黏附分子1的蛋白表达水平也均明显升高,_均明显高于正常对照组（P〈0．05,P〈0．01）,而三七总皂苷能使氧化型低密度脂蛋白损伤的人脐静脉内皮细胞形态趋于正常,活性增强,并明显降低人单核细胞与人脐静脉内皮细胞的黏附率,以及显著降低血管细胞黏附分子1的蛋白的表达水平,与氧化型低密度脂蛋白组相比均有显著性差异（P〈0．05,P〈001）,这种作用随着剂量的增加而增强。结论：三七总皂苷能通过下调血管细胞黏附分子1的表达抑制单核一血管内皮细胞黏附,从而发挥对血管内皮细胞的保护作用,这可能是其治疗动脉硬化闭塞症的机制之一。     

丁苯酞修饰新型自组装短肽对氧化低密度脂蛋白损伤血管内皮细胞的影响

目的 研究丁苯酞修饰新型自组装短肽（NBP-SAP）对氧化低密度脂蛋白（ox-LDL）损伤血管内皮细胞的影响及与信号通路关系。方法 体外培养人脐静脉内皮细胞（HUVECs）并分为NBP-SAP+LY组、NBP-SAP组、oxLDL组和对照组,分别给予NBP-SAP+LY450139+ox-LDL、NBP-SAP+ox-LDL、ox-LDL及对照处理。Realtime-qPCR法检测不同措施处理后HUVECs中血管内皮生长因子（VEGF）/血管内皮生长因子受体-2(VEGFR-2)-Notch1/DLL4通路相关基因表达,Western blot法检测VEGF/VEGFR2-Notch1、DLL4通路相关蛋白表达量,CCK-8法、Annexin-V/PI双染法、Transwell法分别检测各组细胞活力、细胞凋亡率及细胞侵袭力等。结果 NBP-SAP组较ox-LDL组48 h细胞活力及细胞侵袭力增强,细胞凋亡率下降（t分别=3.59、2.91、2.44,P均<0.05）,VEGFR-2、B淋巴细胞瘤-2(Bcl-2)蛋白表达量上调（t分别=12.57、14.49,P均<0.05...     

三七总皂苷对氧化型低密度脂蛋白诱导的人脐静脉内皮细胞血管细胞黏附分子1表达的影响水

背景:氧化低密度脂蛋白能诱导血管内皮细胞活化和黏附分子表达,在动脉粥样硬化形成早期起重要作用.三七总皂苷在心血管系统方面具有保护血管内皮细胞、显著改善动脉粥样硬化病变程度的药理作用.目的:验证三七总皂苷对氧化型低密度脂蛋白损伤内皮细胞后血管细胞黏附分子1的表达及与人单核细胞黏附的影响.设计、时间及地点:体外实验,分组对照,于2007-03/2008-05在北京中医药大学东直门医院中医内科学教育部重点实验室完成.材料:原代人脐静脉内皮细胞为美国Cascade Biologics公司产品;三七总皂苷(血塞通冻干粉针)为黑龙江珍宝岛制药有限公司产品,成分为三七总皂苷,批号:20040207.方法:以培养原代人脐静脉内皮细胞作为靶细胞.用氧化型低密度脂蛋白造成人脐静脉内皮细胞损伤模型.将培养的人脐静脉内皮细胞分为5组:氧化型低密度脂蛋白组(100 mg/L)、氧化型低密度脂蛋白+三七总皂苷组(终浓度分别为200,100,50 mg/L)、正常对照组.主要观察指标:光镜下观察细胞形态变化,四甲基偶氮唑盐法检测细胞活性;采用蛋白定量法检测人脐静脉内皮细胞与单核细胞的黏附率;用流式细胞仪测定人脐静脉内皮细胞的血管细胞黏附分子1的蛋白表达.结果:氧化型低密度脂蛋白作用人脐静脉内皮细胞后12,24 h时,人脐静脉内皮细胞损伤明显,细胞活性显著降低,人单核细胞与人脐静脉内皮细胞的黏附率显著升高,人脐静脉内皮细胞的血管细胞黏附分了1的蛋白表达水平也均明显升高,均明显高于正常对照组(P<0.05,P<0.01),而三七总皂苷能使氧化型低密度脂蛋白损伤的人脐静脉内皮细胞形态趋于正常,活性增强,并明显降低人单核细胞与人脐静脉内皮细胞的黏附率,以及显著降低血管细胞黏附分子1的蛋白的表达水平,与氧化型低密度脂蛋白组相比均有显著性差异(P<0.05,P<0.01),这种作用随着剂量的增加而增强.结论:三七总皂苷能通过下调血管细胞黏附分子1的表达抑制单核-血管内皮细胞黏附,从而发挥对血管内皮细胞的保护作用,这可能是其治疗动脉硬化闭塞症的机制之一.     

低密度、氧化低密度脂蛋白对内皮细胞分泌内皮素的影响

目的 观察低密度脂蛋白（LDL）、氧化低密度脂蛋白（ox-LDL）对内皮细胞分泌内皮素（ET）的影响，以及后者在体外是否对前者具有氧化修饰作用.方法 采用不同浓度的LDL、ox-LDL及LDL＋ox-LDL与脐静脉内皮细胞株ECV-304进行孵育，24 h后分别收集细胞和上清液，采用放免分析法测定ET含量.结果 LDL、ox-LDL均能促进内皮细胞合成、分泌ET，但ox-LDL的作用更显著，而LDL＋ox-LDL组上清ET浓度大于两者单独作用之和.结论 LDL、ox-LDL均能促进内皮细胞合成、分泌ET，但后者的作用更为明显，且在体外对LDL具有氧化修饰作用。     

Pioglitazone decreased CD40/CD40L expression on human umbilical vein endothelial cells induced by oxidized low-density lipoprotein

BACKGROUND: The CD40/CD40 ligand pathway mediated inflammatory processes are important in atherogenesis and the formation of the intraplaque lipid pool. We tested the hypothesis that pioglitazone could decrease lectin-like oxLDL receptor-1 (LOX-1) and CD40/CD40L expression on human umbilical vein endothelial cells (HUVECs) induced by oxidized low-density lipoprotein (oxLDL). METHODS: HUVECs were incubated with oxLDL for 24h with or without pretreated by pioglitazone. Expression of CD40/CD40L on the cell surface was detected by flow cytometry. CD40/CD40L and LOX-1 mRNA expression were evaluated by RT-PCR. The expression of LOX-1 on HUVECs was determined by cell immunohistochemistry. RESULTS: OxLDL increased the expression of CD40 and CD40L in a dose- and time-dependent manner. Pretreatment of HUVECs with pioglitazone (1 and 10 micromol/l) for 60 min decreased the expression of CD40 mRNA induced by oxLDL by 16% and 52%, respectively (both P<0.05). Pretreatment of HUVECs with pioglitazone (1 and 10 micromol/l) for 60 min decreased the expression of CD40L mRNA induced by oxLDL by 16% and 43% (both P<0.05). Also, pretreatment of HUVECs with pioglitazone (1 and 10 micromol/l) for 60 min also significantly decreased CD40 and CD40L expression on HUVECs induced by oxLDL in a concentration-dependent manner. Pretreatment of HUVECs with pioglitazone (1 and 10 micromol/l) decreased oxLDL induced upregulation mRNA of LOX-1 by 11% and 28%, respectively. Furthermore, through immunohistochemistry, we found that pioglitazone could decrease the LOX-1 expression on HUVECs induced by oxLDL. CONCLUSION: Pioglitazone inhibited the upregulation of LOX-1 on HUVECs elicited by oxLDL and subsequently decreased HUVECs CD40/CD40L expression induced by oxLDL. These observations provided novel insight into a potential novel anti-inflammatory pathway of thiazolidinediones.     

久强脑立清对人脐静脉内皮细胞一氧化氮和内皮素分泌的影响

目的观察久强脑力清 (JNQ)含药血清对人脐静脉内皮细胞 (HUVECs)分泌一氧化氮 (NO)和内皮素 (ET 1)的影响 ,探讨其对HUVECs血管活性分子分泌的调节作用。方法取原始JNQ含药血清体积分数的 80 %、40 %、2 0 %、10 %和 5 %作用于原代培养的HUVECs 2 4h后 ,分别检测上清中的NO和EI 1的含量。结果不同浓度的JNQ含药血清作用组的NO、ET 1含量与正常血清对照组比较增加 (P <0 0 5 ) ;NO/ET 1比值随着含药血清浓度的增加 ,比正常血清组增高 (P <0 0 5 )。结论JNQ含药血清通过提高HUVECs分泌NO和ET 1,具有保护内皮细胞功能和维持NO/ET 1平衡的作用     

恒磁场对人脐静脉内皮细胞增殖的影响

目的　研究不同强度的恒磁场对人脐静脉内皮细胞增殖的影响。方法　体外培养的第 3代人脐静脉内皮细胞 ,分为对照组及不同剂量磁场组。各剂量磁场作用组的磁感应强度分别为 0 .0 5mT、0 .1mT、1mT、10mT、30mT、60mT和 10 0mT ,磁场作用时间均为 48h。用3H TdR法及MTT法测定细胞增殖。结果　 0 .0 5mT组细胞增殖显著高于对照组 (0 .2 92± 0 .0 10对 0 .2 2 0± 0 .0 0 8,P <0 .0 5 ) ;0 .1mT组细胞增殖与对照组相比无明显差异 (0 .2 31± 0 .0 0 9对 0 .2 2 0± 0 .0 0 8,P >0 .0 5 ) ;其余剂量组细胞增殖均显著低于对照组 (P <0 .0 5 )。结论　 0 .0 5mT的恒磁场可以促进人脐静脉内皮细胞的增殖     

抑制胞浆型磷脂酶A2活性对内毒素诱导人脐静脉内皮细胞分泌瘦素的影响

目的 通过改变胞浆型磷脂酶A2(cPLA2)的活性,检测细菌脂多糖(LPS)及Ca2+载体A23187诱导的人脐静脉内皮细胞株(ECV-304)上清液中瘦素(Leptin)水平的变化,探讨在体外炎症状态下cPLA2活性与细胞分泌Leptin的关系.方法 体外培养ECV-304细胞.实验1:将细胞分为空白对照组,LPS 3个浓度5、10、20 μg/ml刺激组,Ca2+载体A23187 3个浓度0.1、 1.0、10.0 μmol/L刺激组共7个组,分别作用6、12、24 h后收集上清液.实验2:根据实验1结果将细胞分为空白对照组,LPS 20 μg/ml刺激组,cPLA2特异性抑制剂AACOCF3 3个浓度0.1、1.0、10.0 μmol/L与LPS合用刺激组,丝裂素活化蛋白激酶上游激酶1/2(MEK1/2)抑制剂 U0126 3个浓度0.1、1.0、5.0 μmol/L与LPS合用刺激组共8个组,在LPS刺激前1 h加入AACOCF3或U0126,LPS刺激24 h后收集上清液.采用放射免疫分析法检测Leptin水平.结果 实验1:随LPS刺激浓度增加和时间延长,细胞释放Leptin浓度逐渐减少,LPS 20 μg/ml组作用24 h后Leptin浓度(ng/ml)较空白对照组显著下降(0.540±0.109比0.823±0.048,P<0.05).但A23187对细胞分泌Leptin并无显著影响.实验2:LPS刺激能使细胞分泌Leptin浓度(ng/ml)明显下降(0.558±0.069比0.825±0.067,P<0.05);而用不同浓度AACOCF3或U0126干预后,细胞分泌Leptin的浓度(ng/ml)有所回升,且呈浓度依赖性(AACOCF3 0.1、1.0、10.0 μmol/L组分别为0.673±0.135、 0.723±0.055、 0.797±0.062;U0126 0.1、 1.0、5.0 μmol/L组分别为0.698±0.112、 0.862±0.184、0.935±0.145),AACOCF3 1.0 μmol/L、10.0 μmol/L组和U0126 1.0 μmol/L、5.0 μmol/L组Leptin浓度均显著高于LPS 20 μg/ml刺激组(均P<0.05).结论 在由LPS诱导的体外炎症状态下,Leptin的分泌与cPLA2的活性具有一定的关系.

Abstract：

Objective To determine Leptin levels in supernatant fluid of culture of human umbilical vein endothelial cells (ECV-304) after being challenged by lipopolysaccharide (LPS) and calcium ion vector A23187, and to explore the possible relation between Leptin release and cytosolic phospholipase A2 (cPLA2) activity in an inflammatory cell model. Methods ECV-304 cells were cultured in vitro. Experiment 1: the cells were divided into seven groups: blank control group, LPS 5, 10, 20 μg/ml stimulation groups, A23187 0.1, 1.0, 10.0 μmol/L stimulation groups. The supernatants were collected at 6, 12 and 24 hours. Experiment 2: according to the results of experiment 1, the cells were divided into eight groups: blank control group, LPS 20 μg/ml stimulation group, the inhibitor of cPLA2 AACOCF3 0.1, 1.0, 10.0 μmol/L plus LPS stimulation groups, the inhibitor of mitogen-activated protein/extracellular signal-regulated protein kinase kinase 1/2 (MEK1/2) U0126 0.1, 1.0, 5.0 μmol/L plus LPS stimulation groups, with AACOCF3 or U0126 added 1 hour before the addition of LPS, and the supernatants were collected 24 hours after the addition of LPS. Leptin level was determined by radioimmunoassay. Results Experiment 1: with increase in LPS concentration and prolongation of time, Leptin release was decreased gradually. After 24 hours of interaction the concentration of Leptin (ng/ml) in LPS 20 μg/ml group was decreased significantly compared with the blank control group (0.540±0.109 vs. 0.823±0.048, P<0.05). However, A23187 had no significant effect on Leptin release. Experiment 2: LPS rendered cells to release less Leptin (ng/ml: 0.558±0.069 vs. 0.825±0.067, P<0.05); by adding AACOCF3 or U0126 in different concentration before adding LPS rendered the cells to release more Leptin (ng/ml), and it showed concentration-dependent (the AACOCF3 0.1, 1.0, 10.0 μmol/L groups were 0.673±0.135, 0.723±0.055, 0.797±0.062, respectively; the U0126 0.1, 1.0, 5.0 μmol/L groups were 0.698±0.112, 0.862±0.184, 0.935±0.145, respectively). The release of Leptin in AACOCF3 1.0 μmol/L, 10.0 μmol/L and U0126 1.0 μmol/L, 5.0 μmol/L groups was significantly higher than LPS 20 μg/ml stimulation group (all P<0.05). Conclusion There is a possible relation between Leptin release and cPLA2 activity in inflammatory cells induced by LPS.     

血小板微颗粒对人脐静脉内皮细胞组织因子表达影响的初步探讨

目的探讨血小板微颗粒（PMPs）可刺激人脐静脉内皮细胞（ECV-304）表达组织因子（TF）。方法将一定数量分离于人富血小板血浆（PRP）的PMPs加到ECV-304细胞作用一定时间后,应用逆转录聚合酶链反应（RT-PCR）、流式细胞术检测细胞TF表达。结果一定数量PMPs可刺激ECV-304细胞表达TF,但与相同反应条件下一定浓度内毒素（LPS）作用于ECV-304细胞表达的TF量有所不同。结论PMPs可刺激ECV-304细胞表达TF。     

血小板微颗粒对人脐静脉内皮细胞组织因子表达影响的初步探讨

目的探讨血小板微颗粒(PMPs)可刺激人脐静脉内皮细胞(ECV-304)表达组织因子(TF)。方法将一定数量分离于人富血小板血浆(PRP)的PMPs加到ECV-304细胞作用一定时间后,应用逆转录聚合酶链反应(RT-PCR)、流式细胞术检测细胞TF表达。结果一定数量PMPs可刺激ECV-304细胞表达TF,但与相同反应条件下一定浓度内毒素(LPS)作用于ECV-304细胞表达的TF量有所不同。结论PMPs可刺激ECV-304细胞表达TF。     

替米沙坦对人血管内皮细胞血管紧张素转换酶-2表达的调节作用研究

目的 探讨替米沙坦对人血管内皮细胞血管紧张素转换酶-2（ACE2）表达的影响.方法 原代培养人脐静脉内皮细胞（HUVECs）,以替米沙坦（终浓度分别为10^-7、10^-6、10^-5 mol/L）刺激24 h;以替米沙坦（终浓度为10^-6 mol/L）分别刺激6、12和24 h;以2型血管紧张素Ⅱ受体特异性阻断剂PD123319（终浓度为10^-6 mol/L）单独或与相同终浓度的替米沙坦联合刺激12 h.以蛋白质免疫印迹法（Western blot）检测ACE2蛋白表达量,以逆转录-聚合酶链反应（RTPCR）检测ACE2 mRNA表达.结果 替米沙坦呈剂量（浓度）和时间依赖性使ACE2蛋白及基因表达量显著增加.与对照组比较,替米沙坦在终浓度分别为10^-7、10^-6、10^-5 mol/L时,可使ACE2蛋白表达量分别增加1.5、2.7和4.6倍,使ACE2 mRNA表达分别增加1.2、2.3和4.5倍;于6、12和24 h,替米沙坦（终浓度10-6 mol/L）分别使ACE2蛋白表达量增加1.6、2.7和4.2倍,使ACE2 mRNA表达分别增加1.3、2.3和4.0倍;与对照组及替米沙坦组比较,PD123319对ACE2蛋白及基因表达无影响.结论 替米沙坦呈剂量（浓度）和时间依赖性显著上调ACE2蛋白及基因表达,此作用可能与阻断血管紧张素Ⅱ受体无关.     

Melatonin attenuates homocysteine‐induced injury in human umbilical vein endothelial cells

Homocysteine (Hcy) is a major risk factor for vascular disease and is closely associated with endothelial dysfunction. Melatonin is a neurohormone that is mostly produced by the pineal gland. Studies have reported that melatonin exhibits neuroprotective effects in several neurodegenerative disorders. The aim of the current study was to investigate the possible protective effect of melatonin against Hcy‐induced endothelial cell apoptosis in human umbilical vein endothelial cells (HUVECs) and to explore the underlying mechanisms. HUVECs were exposed to Hcy in the presence or absence of melatonin. The effect of melatonin on viability was examined by MTT assay. Intracellular reactive oxygen species (ROS) levels were determined by 2′,7′‐dichlorofluorescein diacetate (DCF‐DA). Further, expression of Bax, Bcl‐2, and caspase‐3 was analyzed by Western blot analysis. Lipid peroxidation (LPO) levels, total antioxidant power (TAP), and total thiol molecules were also evaluated. The results of this study revealed that melatonin significantly prevented Hcy‐induced loss in cell viability in HUVECs. It was found that ROS significantly increased in the presence of Hcy, whereas melatonin reduced ROS production. Melatonin also downregulated Bax, upregulated Bcl‐2, and decreased the expression and activity of caspase‐3. Hcy increased the levels of LPO, and this effect was significantly attenuated by melatonin. Melatonin also increased the levels of TAP and total thiol molecules. It was concluded that melatonin played a protective role against Hcy‐induced endothelium cell apoptosis through inhibition of ROS accumulation and the mitochondrial‐dependent apoptotic pathway.     

The effect of folic acid on the homocysteine metabolism in human umbilical vein endothelial cells (HUVECs)

Mild hyperhomocysteinaemia is associated with increased risk for vascular disease. We studied homocysteine export from human umbilical vein endothelial cells (HUVECs) by measuring total homocysteine (tHcy) concentrations in the culture medium. Under standard culture conditions tHcy concentrations in the HUVEC culture medium increased by constant amounts after 24, 48 and 72 h [mean = 2.5 (SD ± 0.7) μmol L⁻¹ homocysteine every 24 h]. As the cells are the only source of homocysteine increase in the culture medium, we designate this as homocysteine export from HUVEC. Folic acid supplementation to the culture medium lowered the homocysteine export in a dose-dependent manner. Methyl-tetrahydrofolate (MeTHF) and folinic acid (a stable precursor of MeTHF) were in this respect about 10 times more effective than folic acid. A 50% reduction in the homocysteine export was seen with 10–30 nmol L⁻¹ MeTHF supplementation; reduction to almost zero was seen with 100–300 nmol L⁻¹ MeTHF. Additions to the culture medium of the other vitamins involved in the homocysteine metabolism, such as vitamin B₁₂, vitamin B₆ and flavin adenine dinucleotide, did not show any effect on homocysteine export. Because homocysteine export reflects an imbalance in the homocysteine metabolism, our observations showed a susceptible dependency of this metabolism on folic acid in endothelial cells.