氧化低密度脂蛋白与内皮素在促进血管平滑肌细胞增生中的内在联系

本实验用培养的家兔血管平滑肌细胞探讨了在促进细胞增生过程中，氧化低密度脂蛋白（ｏｘｉｄｉｚｅｄｌｏｗｄｅｎｓｉｔｙｌｉｐｏｐｒｏｔｅｉｎ，ＯＬＤＬ）和内皮素之间的联系，发现二者都可刺激血管平滑肌细胞增生，内皮素Ａ受体拮抗剂ＢＱ１２３可显著抑印制ＯＬＤＬ的促细胞增生作用，￣３Ｈ－ＴｄＲ的掺入量较单纯ＯＬＤＬ组减少１３．３％；细胞培养液内皮素放射免疫测定表明，应用ＢＱ１２３能使内皮素释放量较单纯ＯＬＤＬ组降低２８．９％。免疫细胞化学检测结果亦与上述完全符合，提示在动脉粥样硬化发生中，ＯＬＤＬ促血管平滑肌细胞增生的作用可能部分是通过内皮素来实现的。     

内皮素-1及其受体拮抗剂对血管平滑肌细胞凋亡的影响

目的　探讨内皮素 - 1(ET- 1)及其特异性内皮素 A受体 (ETA- R)拮抗剂 (BQ12 3)对脐动脉血管平滑肌细胞(HUSMC)凋亡的影响。方法　组织块培养 HU SMC,传代后分为对照组、ET- 1组、BQ12 3+ET- 1组。流式细胞术测定细胞核 DNA降解规律、凋亡细胞数、及细胞周期中各时相细胞的变化。结果　 ET- 1组可见明显 Ap峰 ,凋亡细胞百分比 (13.86 %± 4 .85 % )较对照组 (1.5 8%± 0 .2 3% )显著增加 (P<0 .0 5 )。ET- 1组 HUSMC的 G0 / G1 期细胞百分数 (31.5 6 %± 2 .73% ) ,较对照组 (71.15 %± 1.34% )明显降低 (P <0 .0 1)。 S期细胞百分数 (37.6 5 %±3.0 1% )和 G2 / M期细胞百分数 (30 .78%± 0 .30 % ) ,分别较对照组 (19.10 %± 1.99% )和 (12 .2 1%± 1.86 % )明显升高 (P<0 .0 1)。 BQ12 3+ET- 1组各期细胞百分数与相应对照组比较 ,统计学均无差异 (P>0 .0 5 )。结论　 ET- 1促 HU SMC凋亡和增殖的程度不同 ,产生增殖与凋亡的失平衡。BQ12 3可完全抑制 ET- 1的上述作用 ,具有临床应用前景     

内皮素—1在血管成形术后再狭窄形成中的作用

内皮素－１（ＥＴ－１）是一种由２１个氨基酸组成的肽类活性物质，通常在内皮素转换酶的作用下由含有３９个氨基酸的前体转化而来。ＥＴ－１除了具有强大的缩血管作用外，还发现其有促有丝分裂作用，可促进血管平滑肌细胞（ＳＭＣ）增生。在动脉粥样硬化和血管成形术时其...     

内皮素受体拮抗剂 BQ123 对大鼠急性坏死性胰腺炎 E-、P- 选择素表达的影响

目的 观察急性坏死性胰腺炎(ANP)动物模型血管内皮细胞E-选择素和P-选择素(selectin)的变化特点以及用内皮素受体拮抗剂(ET-RA)BQ123治疗后的改变.方法 54只SD大鼠随机分为3组:正常组(n = 6),ANP组(n = 24),BQ123治疗组(ANP + BQ123,n = 24).采用胰腺实质注射牛磺胆酸钠的方法 制作ANP模型,制模后6 h用BQ123进行治疗,监测制模后24 h、48 h、72 h 和7 d血清淀粉酶活性;光镜下观察肺及胰腺组织白细胞浸润情况;免疫组化观察胰腺组织E-选择素、P-选择素表达;RT-PCR检测胰腺组织E-选择素、P-选择素mRNA变化.结果 ANP组肺及胰腺内大量白细胞浸润,而BQ123治疗组白细胞明显减少.ANP组胰腺选择素表达水平显著高于正常组水平,而BQ123治疗组较ANP组显著降低.结论 内皮素受体拮抗剂可通过调控ANP时选择素的表达水平,达到减少白细胞在局部器官浸润,保护器官功能的效果.     

内皮素-1受体拮抗剂对肺气肿大鼠肺组织的保护作用及机制

目的 探讨内皮素-1受体拮抗剂对肺气肿大鼠肺组织的保护作用及机制.方法 将24只SD大鼠随机分为健康对照组、肺气肿模型组、BQ123干预组、Bosentan干预组,每组6只.测4组大鼠平均内衬间隔(MLI)和肺泡破坏指数(DI).用缺口末端标记法(TUNEL)测肺泡间隔细胞凋亡;用免疫组化法、Western blot测caspase-3表达;用明胶酶谱法测基质金属蛋白酶(MMP)-2、MMP-9活性;用ELISA测TNFα、IL-1β浓度.结果 (1)肺气肿模型组大鼠出现典型肺气肿变化,MLI[(108.7±6.8)μm]和DI[(62.2±7.0)%]较健康对照组显著增高[(69.8±6.6)μm;(13.9±2.7)%;P<0.01];BQ123干预组[MLI(89.0±7.4)μm,DI(41.5±4.5)%]、Bosentan干预组[MLI(81.9±6.1)μm,DI(44.0±8.5)%]均较肺气肿模型组显著降低,但2组间差异无统计学意义.(2)4组大鼠肺内均可见凋亡细胞,肺气肿模型组凋亡指数(AI)较健康对照组明显增高,BQ123干预组、Bnsentan干预组AJ较肺气肿模型组明显减低,但仍高于健康对照组(P<0.01).(3)肺气肿模型组大鼠肺组织caspnse-3表达明显增高,BQ123干预组、Bosentan干预组caspase-3表达较肺气肿模型组明显降低.(4)肺气肿模型组大鼠肺内MMP-2、MMP-9活性较健康对照组明显增高,BQ123干预组、Bosentan干预组MMP-2、MMP-9活性降低,但差异无统计学意义.(5)肺气肿模型组大鼠肺组织匀浆上清中TNFα、IL-1β水平较健康对照组明显增高,BQ123干预组、Bosentan干预组TNFα、IL-1β水平较肺气肿模型组明显减低.结论 内皮素受体拮抗剂可通过抑制肺气肿大鼠凋亡基因表达,降低MMPs活性和减少炎性因子释放而起到部分保护作用.     

半边莲生物碱抑制内皮素诱导的大鼠主动脉平滑肌细胞增殖

目的研究半边莲生物碱对内皮素诱导的血管平滑肌细胞增殖的作用。方法用内皮素1剌激大鼠主动脉平滑肌细胞增殖,以细胞计数试剂盒计数细胞个数、氚标胸腺嘧啶脱氧核苷掺入检测DNA的合成量、免疫细胞化学技术观察增殖细胞核抗原的表达活性作为细胞增殖的指标,并应用台盼兰拒染、乳酸脱氢酶检测观察半边莲生物碱的细胞毒性反应。结果内皮素1(10-7mol/L)可明显促进细胞增殖(与对照组相比,P<0.01);半边莲生物碱和BQ-123均可抑制内皮素1所诱导的细胞增殖(与内皮素1组相比,P<0.05);半边莲生物碱的抑制作用与浓度存在明显的依赖关系,但对活细胞数目和乳酸脱氢酶释放量均没有影响(P>0.05)。结论半边莲生物碱(50~200 mg/L)可浓度依赖性地抑制内皮素1所诱导的大鼠主动脉平滑肌细胞增殖,且此抑制作用并非是通过细胞毒性作用实现的。     

内皮素受体拮抗剂预防低氧性肺动脉高压的实验研究

内皮细胞合成的内皮素(ＥＴ)具有极强的促肺血管平滑肌细胞收缩和增生的作用。慢性低氧可引起血浆及肺组织匀浆中ＥＴ1水平升高,ＥＴ通过与ＥＴ1选择性受体(ＥＴＡ)或非选择性受体(ＥＴＢ)结合,参与慢性低氧性肺动脉高压的发病过程。为进一步探讨ＥＴ在低氧性肺动脉高压发病中的作用,本研究采用ＥＴＡ受体拮抗剂ＢＱ123进行预防处理,观察其对低氧性肺动脉高压的预防效应。一、材料和方法1动物模型的复制:雄性Ｗｉｓｔａｒ大鼠30只,体重200～220ｇ。分为低氧组、ＢＱ123组和对照组,每组10只。低氧组:将大鼠置于自制常压低氧舱内,向舱内充入氮…     

血管钙化对血管组织内皮素表达的影响

通过观察血管钙化大鼠血管组织和钙化血管平滑肌细胞内皮素含量的变化 ,探讨血管钙化对血管组织内皮素表达的影响。用维生素D3加尼古丁诱导大鼠血管钙化模型 ,β 磷酸甘油制备钙化血管平滑肌细胞 ,采用VonKossa染色、钙含量测定、4 5Ca聚集及碱性磷酸酶活性测定判断钙化程度 ,放射免疫分析法测定血浆、血管和血管平滑肌细胞培养基中内皮素含量 ,用竞争性定量逆转录聚合酶链反应方法测定血管和血管平滑肌细胞中内皮素mRNA水平。结果发现 :钙化血管平滑肌细胞VonKossa染色见有大量黑色颗粒沉积 ,钙化细胞的钙含量、4 5Ca2 + 摄入及碱性磷酸酶活性分别较正常平滑肌细胞增加 1 1 8%、1 74 %和 7倍 (P均 <0 .0 1 ) ;钙化细胞培养基中内皮素含量较对照组增加 35 % (P <0 .0 5 ) ,内皮素mRNA水平较对照组高 1 2 0 % (P <0 .0 5 ) ;钙化组大鼠血管组织VonKossa染色见血管中层有大量黑色颗粒沉积 ,主动脉钙含量、4 5Ca2 + 沉积及碱性磷酸酶活性分别较对照组高 5 .0倍、1 .4倍和1 .4倍 (P均 <0 .0 1 ) ;钙化大鼠血浆和血管内皮素含量分别较对照组增加 1 0 2 %和 1 0 3% (P均 <0 .0 1 ) ;钙化血管内皮素mRNA水平较正常对照组高 2 2 % (P <0 .0 1 ) ;波生坦处理的大鼠血管钙含量、4 5Ca2 + 聚集及碱性磷酸酶活性较单     

内皮素受体拮抗剂BQ123对大鼠急性坏死性胰腺炎E-、P-选择素表达的影响

目的 观察急性坏死性胰腺炎（ANP）动物模型血管内皮细胞E-选择素和P-选择素（selectin）的变化特点以及用内皮素受体拮抗剂（ET-RA）BQ123治疗后的改变。方法 54只SD大鼠随机分为3组：正常组（n=6），ANP组（n=24），BQ123治疗组（ANP＋BQ123，n=24）。采用胰腺实质注射牛磺胆酸钠的方法制作ANP模型，制模后6h用BQ123进行治疗，监测制模后24h、48h、72h和7d血清淀粉酶活性；光镜下观察肺及胰腺组织白细胞浸润情况；免疫组化观察胰腺组织E-选择素、P-选择素表达；RT—PCR检测胰腺组织E-选择素、P-选择素mRNA变化。结果 ANP组肺及胰腺内大量白细胞浸润，而BQ123治疗组白细胞明显减少。ANP组胰腺选择素表达水平显著高于正常组水平，而BQ123治疗组较ANP组显著降低。结论 内皮素受体拮抗剂可通过调控ANP时选择素的表达水平，达到减少白细胞在局部器官浸润，保护器官功能的效果。     

BQ123对慢性低氧大鼠肺动脉平滑肌细胞KV1.5表达的影响

内皮素1(ET-1)可浓度依赖性的抑制大鼠肺动脉平滑肌细胞(PASMCs)电压门控钾电流(IKv)，但ET-1对PASMCs电压门控钾通道(Kv)基因表达的调节目前尚少见报道，本组研究拟从mRNA和蛋白水平，阐明内皮素受体拮抗剂BQ123对PASMCs Kv1．5表达的影响。     

Combined endothelin receptor blockade evokes enhanced vasodilatation in patients with atherosclerosis

Endothelin (ET)-1 causes vasoconstriction via ET(A) and ET(B) receptors located on vascular smooth muscle cells and vasodilatation via ET(B) receptors on endothelial cells. Studies in vitro indicate an upregulation of ET(B) receptors in atherosclerosis. The present study investigated the vascular effects evoked by endogenous ET-1 in atherosclerotic patients. Forearm blood flow (FBF) was measured with venous occlusion plethysmography in 10 patients with atherosclerosis and in 10 healthy control subjects during intra-arterial infusion of selective ET receptor antagonists. The ET(B) receptor antagonist BQ788 evoked a significant increase in FBF (31+/-13%) in the patients, whereas a 20+/-9% reduction was observed in the control subjects. The ET(A) receptor antagonist BQ123 combined with BQ788 evoked a marked increase in FBF (102+/-25%) in the patients compared with no effect in the control subjects (-3+/-9%, P<0.001 versus patients). The ET(A) receptor antagonist BQ123 increased FBF to a similar degree in patients (39+/-11%) as in control subjects (41+/-11%). The increase in FBF evoked by selective ET(A) receptor blockade was significantly (P<0.05) less than that evoked by combined ET(A)/ET(B) receptor blockade in the atherosclerotic patients. These observations suggest an enhanced ET-1-mediated vascular tone in atherosclerotic patients, which is at least partly due to increased ET(B)-mediated vasoconstriction.     

银杏叶对血管平滑肌细胞增殖活性的影响

目的研究银杏叶对血管平滑肌细胞增殖活性的影响。方法对大鼠的胸主动脉平滑肌细胞采用组织块培养法,用四氧基偶氮硝基唑蓝（MTT）法测定细胞活性。结果与正常对照组比较,高糖（30mmol/L）在24h、48h、72h均有较强的促进大鼠VSMC增殖作用（P〈0.01）;与高糖组比较,不同剂量的EGB对过度增长的VSMC有抑制作用（P〈0.05）。结论EGB制剂可抑制高糖引起的VSMC过度增殖。     

过氧化氢酶过度表达对血管平滑肌细胞凋亡的影响

目的 探讨腺病毒戢体介导的过氧化氢酶基因转染对体外培养的人血管平滑肌细胞凋亡的影响。方法 用含过氧化氢酶基因的重组腺病毒转染人血管平滑肌细胞，采用Western blot方法检测血管平滑肌细胞过氧化氢酶的表达。应用流式细胞术、TUNEL法等方法检测血管平滑肌细胞的凋亡。结果 含过氧化氢酶基因的重组腺病毒转染后血管平滑肌细胞过氧化氢酶表达明显增多；流式细胞术显示含过氧化氢酶基因的重组腺病毒组与对照组比较凋亡率明显增加（P〈0．01）。经TUNEL分析显示，含过氧化氢酶基因的重组腺病毒组凋亡细胞明显多于对照组。两者之间有显著性差异（P〈0．001）。结论 腺病毒载体介导的过氧化氢酶基因转染导致过氧化氢酶过度表达。促进人血管平滑肌细胞的凋亡，这可能是防治经皮腔内冠状动脉血管成形术后再狭窄的一种新方法。     

Role of endothelin in stress-induced hypertension

In this study we investigated the role of endogenous endothelin in the cardiovascular response to acute stress, ie mild footshocks in conscious rats. Footshock-stress significantly increased mean arterial pressure and heart rate (P < 0.05). Peripheral or intracerebroventricular (IVT) administration of BQ 788, a selective antagonist of ET(B) receptor, did not alter pressor response to footshocks. Intraperitoneal injections of BQ 123 (1 mg/kg), a selective antagonist of the ET(A)-receptor, had a tendency to decrease, while BQ 123 (203 ng/5 microl) IVT administration significantly reduced the pressor response to footshocks (-12 mm Hg, P < 0.001). Neither ET(A) nor ET(B) antagonists, when injected centrally or peripherally, altered basal blood pressure or heart rate. Our results may indicate a role of brain endothelin in the sympathetic mediated cardiovascular response to stress, via stimulation of ET(A) receptor.     

Endothelin is a potent mitogen for rat vascular smooth muscle cells

The effect of endothelin (ET), a novel endothelium-derived vasoconstrictive peptide, on DNA synthesis was studied in cultured rat vascular smooth muscle cells (VSMC). ET stimulated incorporation of [3H]thymidine into DNA of the quiescent VSMC in a dose-dependent manner; the approximate half-maximal and maximal stimulation for DNA synthesis was induced with 2 x 10(-10) M and 10(-9) M, respectively. The stimulatory effect by ET on DNA synthesis was completely inhibited by the calcium channel blocker nifedipine. ET combined with epidermal growth factor and transforming growth factor-alpha, but not with platelet-derived growth factor, had synergistic effects. These data indicate that ET is a potent mitogen as well as a constrictor for VSMC, suggesting its potential role in the development of vascular disease.     

Maturational changes of endothelial vasoactive factors and pulmonary vascular tone at birth.

The aim of this study was to determine which endothelial factors were involved in the decrease of pulmonary vascular resistance at birth, and how they changed with maturation. Response of intrapulmonary artery rings precontracted with prostaglandin F2alpha were studied from piglets aged <2 h, 2-3 day, 10 day and adult pigs for pharmacological responses to acetylcholine (ACh) and cromakalim (CMK) in the presence and the absence of the nitric oxide synthase (NOS) inhibitor, N(omega)-nitro-L-arginine (L-NA), the adenosine triphosphate sensitive potassium (K(ATP)) channel blocker, glibenclamide and the endothelin (ET)-A receptor antagonist, BQ123. In situ hybridization and immunochemistry studies were performed in lung tissues of the same animals in order to determine the expression of NOS and ET. There was a small contractile effect of ACh in the newborn. Relaxation to ACh, which was blocked by L-NA and reduced by glibenclamide, only appeared from the age of 3 days. The significantly greater relaxation to CMK in rings without endothelium (p<0.05) was abolished by BQ123 in the newborn, and then disappeared by 2 days of age. Glibenclamide had a greater inhibitory effect on relaxation induced by CMK at 10 days than in the newborn and 2 days old piglets. NOS expression was low in pulmonary arteries of the newborn and increased by 2 days of age whereas the converse was seen with ET expression. It is concluded that: 1) relaxant response to acetylcholine was absent at birth and appeared at 2 days; 2) the reduced relaxant response to cromakalin in rings with endothelium at birth could be blocked by BQ123; and 3) the expression of endothelin decreased whereas the expression of nitric oxide synthase increased from birth to 2 days of age.