球囊损伤后血管迁徙平滑肌细胞弹性蛋白酶mRNA的表达

目的 探讨血管平滑肌细胞有否弹性蛋白酶mRNA的表达,其在血管组织中的分布及与细胞迁徙的关系。方法 采用电囊损伤大鼠动脉的模型,克隆成大鼠胰腺弹性蛋白酶Ⅱ的RNA探针,运用原位杂交及免疫组化,电镜等方法。结果 弹性蛋白酶ⅡmRNA的表达见于正常动脉部分滑肌细胞,并因血管损伤而增强,中膜迁徙性平滑肌细胞均有弹性蛋白酶mRNA的强烈表达,其细胞周围基质显减少,内弹性板遭到破坏。结论 中膜平滑肌细胞的丝氨酸弹性蛋白表达亢进是促进向内膜迁徙并形成平滑肌增生性血管疾病的重要机制之一。     

罗格列酮抑制体外培养大鼠血管平滑肌细胞的增殖和迁移作用

目的 探讨罗格列酮对大鼠主动脉平滑肌细胞增殖及迁移行为的影响.方法 组织贴块法原代培养大鼠主动脉平滑肌细胞,胞浆内免疫组织化学染色鉴定细胞.取第5代纯化细胞无血清培养使细胞同步,用血小板源性生长因子BB或碱性纤维细胞生长因子诱导细胞增殖和迁移,之前不加或加入罗格列酮(1、5和10μmol/L)进行预处理.应用免疫组织化学染色法检测细胞核内增殖细胞核抗原的表达,流式细胞仪分析细胞周期分布,Boyden趋化小室观测细胞迁移能力.结果 罗格列酮能够显著抑制血小板源性生长因子BB或碱性纤维细胞生长因子诱导的平滑肌细胞核内增殖细胞核抗原的表达,抑制细胞由G0/G1期向S期的转变,抑制细胞在Boyden室间的迁徙,且呈明显的荆量依赖关系(P<0.0001).结论 罗格列酮能够抑制血小板源性生长因子BB或碱性纤维细胞生长因子诱导的血管平滑肌细胞的增殖和迁移.     

反义寡核苷酸抑制兔血管平滑肌细胞增殖和血小板源性生长因子β mRNA的表达

目的　应用血小板源性生长因子 β(PDGF β)cDNA的反义寡核苷酸作为药物 ,在体抑制兔血管平滑肌细胞 (VSMCs)增生 ,为人血管再狭窄的防治提供依据。方法　建立兔髂动脉再狭窄模型 ,用自行设计合成的PDGF βcDNA的反义寡核苷酸片段作为药物 ,在体原位观察对VSMCs表达PDGF βmRNA、增殖细胞核抗原和内膜增生的影响。 结果　这种反义寡核苷酸药物显著抑制球囊损伤后 1周内膜VSMCs表达PDGF βmRNA和增殖细胞核抗原 ,抑制率分别为 88 4 0 %和 93 4 4 %。 结论　设计的反义寡核苷酸药物可以通过下调VSMCs表达PDGF βmRNA抑制内膜增生 ,为转基因防治人血管再狭窄提供体内实验依据。     

血小板源生长因子对大鼠血管平滑肌细胞表达基质金属蛋白酶2的影响

目的研究血小板源生长因子对血管平滑肌细胞迁移的影响和细胞产生基质金属蛋白酶2的变化。方法体外培养的血管平滑肌细胞经血小板源生长因子处理0 min、20 min和6 h后进行如下检测:迁移实验观察细胞在盖玻片上的迁移情况;明胶酶谱检测血管平滑肌细胞分泌基质金属蛋白酶2活性;基因芯片和逆转录-聚合酶链反应技术检测血管平滑肌细胞表达基质金属蛋白酶2 mRNA的变化。结果细胞迁移实验显示随着作用时间的延长,血小板源生长因子明显促进细胞的迁移,血小板源生长因子处理20 min和6 h后迁移距离(分别为4.9±0.5、7.1±1.2μm)是对照组(2.3±0.15μm)的2.13倍和3.09倍,差异有显著性(P<0.05);明胶酶谱测定表明:血小板源生长因子显著提高血管平滑肌细胞分泌的基质金属蛋白酶2的活性,作用20 min与6 h后(分别为480.7±27.3和851.5±56.4)是对照组(296.7±15.8)的1.62倍和2.87倍(P<0.01);血小板源生长因子对血管平滑肌细胞表达基质金属蛋白酶2有明显的诱导作用,作用20 min与6 h后的表达(分别为0.54±0.09和0.77±0.04)是对照组(0.3...     

γ干扰素对兔血管内膜损伤后平滑肌细胞表达血小板源性生长因子B-mRNA和增殖的影响

目的探讨γ干扰素抑制血管内膜增生和防治血管再狭窄的体内机制。方法建立兔血管狭窄模型,动态观察肌内给予重组γ干扰素对损伤后不同时期血管内膜平滑肌细胞(vSMCs)原位表达血小板源性生长因子B链mRNA(PDGF-BmRNA)和增殖细胞核抗原的影响。结果γ干扰素显著抑制1周和4周时内膜vSMCs表达增殖细胞核抗原,抑制率分别为88.5％和58.9％;显著抑制各观察时期新生内膜表达PDGF-BmRNA。结论γ干扰素通过下调vSMCs原位表达PDGF-BmRNA抑制血管vSMCs的增殖和内膜增生,可能用于临床再狭窄的防治。     

凝血酶对大鼠血管平滑肌细胞血小板源生长因子受体基因表达的影响

为了研究凝血酶对血管平滑肌细胞血小板源生长因子受体基因表达的影响 ,探讨凝血酶刺激血管平滑肌细胞增殖的机制 ,通过培养SD大鼠胸主动脉血管平滑肌细胞 ,用斑点杂交检测凝血酶对血管平滑肌细胞血小板源生长因子受体mRNA的表达。结果发现培养的血管平滑肌细胞在基础状态下可表达血小板源生长因子α受体和 β受体mRNA ,凝血酶在作用于血管平滑肌细胞 2～ 12h抑制了血管平滑肌细胞血小板源生长因子α受体 β受体mRNA的表达 ,2 4～ 48h后血管平滑肌细胞血小板源生长因子α受体 β受体mRNA的表达恢复到基础状态。提示凝血酶对血管平滑肌细胞具有较强的促增殖作用 ;凝血酶显著降低了血管平滑肌细胞血小板源生长因子α受体 β受体mRNA的表达     

血小板源生长因子β受体反义寡核苷酸对血小板源生长因子诱导大鼠血管平滑肌细胞迁移的影响

为研究血小板源生长因子β受体反义寡核苷酸对血小板源生长因子诱导的大鼠血管平滑肌细胞迁移的影响和作用机制，利用激光共聚集显微镜观察平滑肌细胞对异硫氰酸荧光素标记的反义寡核苷酸的摄取和细胞内定位，改良Boden's小室法观察平滑肌细胞迁移。结果发现，加入反义寡核苷酸培养24h及48h后荧光分别位于细胞浆内和细胞核内，5umol/L以上浓度反义寡核苷酸作用36h后，被血小板源生长因子诱导迁移通过Boyden's小室碳纤维素膜的细胞数量小于空白对照组；正义，错义寡核苷酸和5umol/L以下浓度反义寡核苷酸迁移抑制不明显，提示血小板源生长因子β受体反义寡核苷酸在细胞核内呈时间和浓度依赖性抑制血小板源生长因子诱导的血管平滑肌细胞迁移。     

血小板源生长因子诱导核受体Nur77调节血管平滑肌细胞增殖

目的 研究血小板源生长因子诱导血管平滑肌细胞中核受体Nur77表达机制及其与血管平滑肌细胞增殖的关系,探讨阿托伐他汀对血小板源生长因子诱导的血管平滑肌细胞增殖和核受体Nur77表达的关系.方法 分离培养鼠血管平滑肌细胞,分别与PD98059、阿托伐他汀、核受体Nur77siRNA孵育后应用血小板源生长因子刺激,检测核受体Nur77、细胞外调节蛋白激酶表达;检测增殖细胞核抗原表达.结果 血小板源生长因子诱导的血管平滑肌细胞中核受体Nur77通过ERK-MAPK信号途径表达.阿托伐他汀减少血小板源生长因子诱导的核受体Nur77表达,抑制血管平滑肌细胞增殖.在核受体Nur77沉默后的血管平滑肌细胞中,血小板源生长因子诱导的细胞增殖减少.结论 血小板源生长因子诱导的血管平滑肌细胞增殖受核受体Nur77调控,阿托伐他汀降低核受体Nur77表达,减少血管平滑肌细胞增殖,这可能是他汀类药物抗细胞增殖的新的途径.核受体Nur77可能是减少再狭窄的新的治疗靶点.     

氟伐他汀对兔髂动脉内皮剥脱后细胞增殖的影响

探讨氟伐他汀对兔髂动脉内皮剥脱后造成的动脉粥样硬化模型中细胞增殖的影响。将雄性新西兰兔随机分为氟伐他汀组 (n =2 8)和对照组 (n =2 8) ,用球囊导管剥脱内皮及高胆固醇饮食造成动脉粥样损伤 ,分别在内皮损伤后 1、2、4、8周处死动物并取髂动脉 ,用常规免疫组织化学染色和计算机图像分析方法观察氟伐他汀对新生内膜中平滑肌细胞增殖和血小板源生长因子 BB的影响。结果发现 ,氟伐他汀组内膜中增殖细胞核抗原染色阳性细胞率明显少于对照组 (P <0 .0 5 ) ;氟伐他汀组血小板源生长因子 BB含量一直处于较低水平 ,且明显低于对照组 (P <0 .0 5 ) ;血管内膜增殖细胞核抗原染色阳性细胞率与血小板衍生因子 BB含量的相关系数为 0 .712 7(P <0 .0 1)。提示氟伐他汀可能部分通过抑制血小板源生长因子 BB合成和分泌而抑制平滑肌细胞增殖。     

碱性成纤维细胞生长因子在烟草烟雾诱导大鼠血管平滑肌细胞增殖中的作用

目的探讨烟草烟雾提取物对大鼠血管平滑肌细胞增殖的影响及碱性成纤维细胞生长因子在其中的作用。方法按不同浓度烟草烟雾提取物(0、2.5%、5%、10%和20%)分为对照组、低浓度、中等浓度、高浓度和过高浓度烟草烟雾提取物组刺激血管平滑肌细胞,采用MTT法观察细胞增殖变化,免疫细胞化学法测定碱性成纤维细胞生长因子和增殖细胞核抗原蛋白的表达,同时用逆转录-聚合酶链反应法检测碱性成纤维细胞生长因子mRNA表达。用筛选出的最适烟草烟雾提取物浓度处理大鼠血管平滑肌细胞不同时间(0、4、8、12 h和24 h)后,检测碱性成纤维细胞生长因子mRNA及碱性成纤维细胞生长因子和增殖细胞核抗原蛋白的变化。用碱性成纤维细胞生长因子抗体和最适浓度烟草烟雾提取物干预血管平滑肌细胞24 h后检测细胞增殖及碱性成纤维细胞生长因子和增殖细胞核抗原蛋白表达的变化。结果 (1)与对照组相比,低浓度烟草烟雾提取物组(P0.05)和中浓度组血管平滑肌细胞增加明显(P0.01),而高浓度组和过高浓度组与对照组比较差异无显著性(P0.05)。碱性成纤维细胞生长因子mRNA、蛋白和增殖细胞核抗原蛋白在对照组中有少量表达,低浓度烟草烟雾提取物组表达增加(P0.01),中浓度烟草烟雾提取物组达到高峰,高浓度和过高浓度烟草烟雾提取物组仍高于对照组(P0.01)。(2)对照组(不加烟草烟雾提取物组即0 h组)血管平滑肌细胞中有少量碱性成纤维细胞生长因子mRNA、蛋白和增殖细胞核抗原蛋白表达。低浓度烟草烟雾提取物刺激4 h后细胞内碱性成纤维细胞生长因子mRNA、蛋白和增殖细胞核抗原蛋白表达增加(P0.01),碱性成纤维细胞生长因子mRNA于8 h达高峰;碱性成纤维细胞生长因子和增殖细胞核抗原蛋白于12 h达高峰。(3)碱性成纤维细胞生长因子抗体可显著抑制5%烟草烟雾提取物诱导的血管平滑肌细胞增殖和碱性成纤维细胞生长因子、增殖细胞核抗原蛋白表达增加。结论低浓度和中浓度烟草烟雾提取物对大鼠血管平滑肌细胞的促增殖作用逐渐增加;高浓度和过高浓度组时促增殖作用反而减弱。烟草烟雾提取物可能是通过增加碱性成纤维细胞生长因子的表达促进大鼠血管平滑肌细胞的增殖。     

Effect of Probucol on Smooth Muscle Cell Proliferation and Dedifferentiation After Vascular Injury in Rabbits: Possible Role of PDGF

We previously reported a clinical study in which probucol reduced the restenosis rate. The mechanism of this effect is unclear. Restenosis is characterized by neointimal hyperplasia caused by proliferation of smooth muscle cells (SMCs), which increases the expression of Platelet-derived growth factor (PDGF)-A and SMemb. SMemb, a non–muscle-type myosin heavy chain most predominantly expressed in embryonic smooth muscle, can be used as a good molecular marker for dedifferentiated SMC. The aim of this study was to analyze the effect of probucol on neointimal proliferation and the level of expression of PDGF-A and SMemb after balloon injury in rabbits. Probucol was given orally 1.3 g/d from 2 weeks prior to carotid balloon injury to the time of killing (2 or 4 weeks after balloon injury). Intimal area was determined histologically using a computerized morphometry program. For quantification of SMC proliferation, alpha-actin–positive cells and proliferating cell nuclear antigen (PCNA)-labeled cells were counted. The expression of PDGF-A and SMemb mRNA was analyzed by the RNase protection assay. SMemb expression was also examined by immunohistochemistry. Probucol remarkably decreased intimal area by 70% and the number of SMC and PCNA-labeled cells in the intima. The expression of PDGF-A mRNA was significantly increased after balloon injury in untreated rabbits, whereas it was markedly suppressed with probucol treatment. The expression of SMemb was significantly increased in injured arteries at mRNA and protein levels. However, probucol did not suppress SMemb expression. Probucol is effective in preventing SMC proliferation, which is possibly due to a decrease in the expression of PDGF.     

Regulation of platelet-derived growth factor ligand and receptor gene expression by alpha-thrombin in vascular smooth muscle cells.

Since the expression of genes for platelet-derived growth factor (PDGF)-A and PDGF beta-receptor are reciprocally regulated in vascular wall cells after balloon injury, we have investigated the ability of specific vasoactive molecules or growth factors to reproduce the injury pattern of gene expression in cultured rat smooth muscle cells (SMCs) and assessed the effect of inactivating alpha-thrombin on injury-induced expression of PDGF-A mRNA by vascular wall cells in vivo. The molecules investigated, to which vascular SMCs may be locally exposed after mechanical injury, included vasoactive factors (alpha- and beta-adrenergic agonists, serotonin, histamine, angiotensin II, and endothelin) and growth factors (PDGF-AA, PDGF-BB, basic fibroblast growth factor, insulin-like growth factor, epidermal growth factor, and alpha-thrombin). In cultured rat SMCs, only alpha-thrombin (0.1-100 nM), among these compounds, produced the pattern of transiently increased PDGF-A and decreased PDGF beta-receptor mRNA. PDGF-B chain mRNA levels remained undetectable in these cultured SMCs. The dependence of these changes in gene expression on the proteolytic activity of alpha-thrombin was shown by the interruption of altered gene expression or DNA synthesis after incubating the cultured SMCs with covalently inactivated alpha-thrombin using D-Phe-Pro-Arg chloromethyl ketone, a synthetic direct active-site irreversible inhibitor of alpha-thrombin. Continuous intravenous infusion of this synthetic antithrombin into baboons for 6 hours (100 nmol/kg per minute maintaining constant plasma levels of 3.0 +/- 0.5 microns/ml) after inducing balloon-catheter arterial injury also prevented the threefold increase in expression of PDGF-A mRNA characteristically exhibited by untreated mechanically injured vessels.(ABSTRACT TRUNCATED AT 250 WORDS)     

神经肽Y对血管平滑肌增殖细胞核抗原、血小板源性生长因子和c-myc基因表达的影响

以体外培养的血管平滑肌细胞模型为研究对象,在运用免疫荧光细胞组织化学技术和激光共聚焦显微镜定量研究神经肽Y的作用下,观察血管平滑肌细胞中增殖细胞核抗原、血小板源性生长因子和c- myc 原癌基因表达的平均荧光值变化,以阐明神经肽Y 参与高血压和动脉粥样硬化等心血管疾病发生的病理机制。结果发现,对照组中增殖细胞核抗原、血小板源性生长因子和c- myc 原癌基因表达的平均荧光值分别为1542.71 ±200.04 、815.28±116.48 和1620.26±174.58,神经肽Y则可促进增殖细胞核抗原、血小板源性生长因子和c- myc 原癌基因在血管平滑肌细胞中的表达,其平均荧光值分别为1648.56±232.71、1225 .46±101 .84 和1740 .35 ±205 .91,其中以血小板源性生长因子的表达差异最为明显(P< 0.01)。结果提示,神经肽Y可促进血管平滑肌细胞的增殖,并诱导血小板源性生长因子和c- myc 原癌基因表达增强。     

Migration of adventitial myofibroblasts following vascular balloon injury: insights from in vivo gene transfer to rat carotid arteries

OBJECTIVES: Migration of adventitial fibroblasts, in addition to smooth muscle cell proliferation, plays a role in neointima formation following vascular injury. Previous studies have not directly addressed whether endogenous adventitial cells migrate towards the intima following balloon injury in the absence of medial dissection. We have employed an in vivo gene transfer technique to the rat carotid artery to directly label adventitial fibroblasts prior to balloon injury. METHODS: An adenoviral vector coordinating expression of nuclear targeted beta-galactosidase (AdLacZ) suspended in pluronic gel was applied to the perivascular surface of left carotid arteries of male Sprague-Dawley rats. Balloon catheter mediated vascular injury was performed on these arteries 4 days later and animals killed at 3, 7 and 14 days after injury. RESULTS: Expression of LacZ up to 14 days after application of the adenovirus was restricted only to the adventitia of uninjured arteries and absent from untransfected right carotid arteries. However, following balloon catheter injury, LacZ positive cells were observed within the medial layer of vessels by 3 days, and contributed to the population of cells within the neointima at 7-14 days. Adventitial cells in uninjured arteries did not express smooth muscle alpha-actin but after injury, LacZ positive cells migrating towards the lumen exhibited alpha-actin immunostaining, suggesting their change to a myofibroblastic phenotype. CONCLUSIONS: These findings provide direct evidence that adventitial fibroblasts migrate and contribute to neointima formation after balloon injury and show that in vivo gene transfer to the adventitia results in sustained transgene expression capable of labelling migrating adventitial cells within the media and neointima of injured vessels.     

水蛭素对凝血酶诱导的血管平滑肌细胞增殖的影响

为研究重组水蛭素对凝血酶诱导的兔胸主动脉血管平滑肌细胞增殖的影响及其作用机制.选用第2～5代培养的血管平滑肌细胞,在与凝血酶(4.0 ku/L)共同孵育的条件下,分别给予水蛭素(6.0 ku/L)和肝素(6.O ku/L)进行干预.通过四唑盐比色实验检测细胞生长活性,流式细胞术检测细胞周期,免疫组织化学检测血小板生长因子和增殖细胞核抗原在血管平滑肌细胞中的表达.结果发现,重组水蛭素能明显抑制凝血酶诱导的平滑肌细胞增殖,其抑制作用可能与减低了血管平滑肌细胞对血小板生长因子和增殖细胞核抗原的表达有关.     

Adenovirus-encoded hammerhead ribozyme to PDGF A-chain mRNA inhibits neointima formation after arterial injury

To develop a strategy for gene therapy of restenosis following coronary angioplasty, we examined the effects of a recombinant adenovirus vector encoding a hammerhead ribozyme specific for rat platelet-derived growth factor (PDGF) A-chain mRNA (Ad.Ribozyme) and a control recombinant adenovirus vector encoding the Escherichia coli LacZ gene (Ad.LacZ) on neointima formation in rat carotid artery after balloon injury. Ad.Ribozyme (10(8) PFU/ml) markedly reduced the increased expression of PDGF A-chain mRNA and protein. Ad.Ribozyme significantly decreased the intima/media ratio (68%) of the injured artery, whereas Ad.LacZ had no effect on the intima/media ratio. Most carotid arteries developed thrombi by 14 days after balloon injury, whereas Ad.Ribozyme completely inhibited thrombus formation. Expression of thromboxane A2 (TXA2) receptor mRNA was significantly increased after balloon injury. Ad.Ribozyme significantly decreased the levels of TXA2 receptor. Expression of prostaglandin I2 (PGI2) synthase mRNA was significantly decreased after balloon injury. Ad.Ribozyme significantly increased levels of PGI2 synthase mRNA after balloon injury. The observation that adenovirus-encoded ribozyme to PDGF A-chain inhibits neointima formation may serve as a novel strategy to prevent restenosis after coronary angioplasty. Inhibition of growth factors by genetic approaches may yield new insights into the mechanisms underlying responses to vascular injury and lead to new therapeutic applications.     

水蛭素对凝血酶诱导的血管平滑肌细胞增殖的影响

为研究重组水蛭素对凝血酶诱导的免胸主动脉血管平滑肌细胞增殖的影响及其作用机制。选用第2～5代培养的血管平滑肌细胞，在与凝血酶(4．0ku／L)共同孵育的条件下，分别给予水蛭素(6．0ku／L)和肝素(6．0ku／L)进行干预。通过四唑盐比色实验检测细胞生长活性，流式细胞术检测细胞周期，免疫组织化学检测血小板生长因子和增殖细胞核抗原在血管平滑肌细胞中的表达。结果发现，重组水蛭素能明显抑制凝血酶诱导的平滑肌细胞增殖，其抑制作用可能与减低了血管平滑肌细胞对血小板生长因子和增殖细胞核抗原的表达有关。