不同频率张应变对大鼠血管平滑肌细胞α-肌动蛋白表达的影响

目的研究不同频率张应变对血管平滑肌细胞表型转换的影响。方法应用FX-4000T细胞应变加载系统,对体外培养的大鼠血管平滑肌细胞施加10％应变,频率分别为0．5Hz、1Hz和2Hz,加载时间12h和24h后,采用Real time RT-PCR、Western blot、免疫荧光化学等技术检测不同频率张应变下血管平滑肌细胞的alpha-肌动蛋白（α-actin）的表达变化。以未加载张应变的血管平滑肌细胞为对照组。结果血管平滑肌细胞的α-actin的蛋白和RNA表达量在1Hz条件下比相同时相点的其他频率组均高。结论 不同频率的张应变可以影响血管平滑肌细胞α-actin的表达量,提示应变频率的改变可能参与血管平滑肌细胞表型转换的调节。     

在高血压动脉重建中microRNA-21对血管平滑肌细胞细胞外基质表达的调控作用

目的探讨在高血压动脉重建中microRNA-21(miR-21)对血管平滑肌细胞(vascular smooth muscle cells,VSMCs)细胞外基质(extracellular matrix,ECM)的调控作用及其机制。方法建立腹主动脉缩窄型大鼠高血压模型,大鼠分为假手术对照组、高血压2周组和高血压4周组;对体外培养的大鼠主动脉VSMCs施加频率为1.25 Hz周期性张应变,加载幅度分别为0%(静态对照组)、5%(正常张应变组)、15%(模拟高血压状态的高张应变组),加载持续时间均为12 h。采用Western blotting和Real time RT-PCR技术,分别检测动脉和细胞样品ECM以及miR-21的表达。用miR-21特异干扰片段抑制培养的VSMCs miR-21表达,然后检测VSMCs的ECM、miR-21和Smad 7表达变化。结果与假手术对照组相比,高血压2周组胸主动脉ECM和miR-21的表达显著上升;高血压4周组胸主动脉的I型胶原、III型胶原和miR-21表达显著上升。与静态对照组和5%张应变组相比,15%张应变组VSMCs的I型胶原表达无显著变化,而III型胶原表达显著升高,Smad 7表达显著下降,周期性张应变增强VSMCs的miR-21表达。干扰miR-21降低周期性张应变状态下VSMCs的miR-21表达以及III型胶原蛋白水平表达,上调VSMCs的Smad 7表达。结论高血压血管重建导致大鼠胸主动脉ECM和miR-21高表达。周期性高张应变可诱导VSMCs的miR-21高表达,再通过其调节Smad 7蛋白,进而调控VSMCs的ECM,尤其是III型胶原的表达,参与高血压血管重建。     

细胞外基质对血管平滑肌细胞的作用

血管平滑肌细胞表型的转变、迁移、增殖和凋亡,与血管成型术后再狭窄的发生关系密切,细胞外基质通过与平滑肌细胞表面整合素受体的粘连,形成粘着斑,激活粘着斑激酶,影响细胞内的信号转导,从而对再狭窄的发生和发展产生一定作用。     

不同频率张应变作用下血管磷酸化HSP27的表达及其在血管平滑肌细胞迁移中的作用

目的研究血管和血管平滑肌细胞(vascular smooth muscle cells,VSMCs)磷酸化热休克蛋白27(heat shock protein27,HSP27)在不同频率张应变条件下的表达变化及其对VSMCs迁移的影响。方法应用血管体外应力培养系统,在频率为0.5Hz和1.25Hz、平均压力15.996 kPa(120mmHg)和平均流量50mL/min的条件下培养猪颈总动脉,培养时间为24h;又用Flexercell细胞应变加载系统,对人VSMCs施加0.5Hz和1.25Hz频率的10%张应变,加载时间为12h。然后,Western blot检测不同频率张应变作用下血管和VSMCs的磷酸化HSP27的表达变化。应用RNA干扰技术,分别观察抑制HSP27表达前后的VSMCs迁移能力变化。结果与频率为0.5Hz作用相比,1.25Hz张应变可以激活血管和VSMCs的HSP27表达,抑制VSMCs迁移。RNA干扰HSP27后,VSMCs迁移数量明显增多。结论正常生理频率张应变可能通过激活血管HSP27抑制VSMCs迁移,以维持血管正常的结构和功能。     

细胞外基质及其筑构对平滑肌细胞增殖的影响

目的:研究细胞外基质层粘连蛋白(Laminin,LN),纤维连接蛋白(Fibronecfin,FN)和三维基膜基质Matrigel胶对平滑肌细胞增殖的作用。方法:将用酶消化法分离的兔主动脉平滑肌细胞种植在LN和FN上及三维基膜基质Matrigel胶里,然后用Brdu法检测各平滑肌细胞的增殖率。结果:生长在FN上的平滑肌细胞增殖率最高(24%),生长在LN上的平滑肌细胞增殖率次之(17%),而生长在三维基膜基质胶里的平滑肌细胞未出现细胞增殖,另外LN较FN有明显的促进平滑肌细胞分化成熟的作用。结论:细胞外基质成分和基质筑构对平滑肌细胞的增殖与分化具有重要的调节作用。     

机械张应变诱导蛋白激酶B活化对血管平滑肌细胞迁移的影响

目的研究机械张应变诱导蛋白激酶B活化对大鼠血管平滑肌细胞迁移能力的影响。方法应用FX-4000T细胞应变加载系统,对大鼠血管平滑肌细胞施加牵拉幅度为15%、频率为1Hz的张应变。以Transwell和Westernblot等方法观察张应变作用下蛋白激酶B磷酸化和血管平滑肌细胞迁移能力的变化,以未加载张应变的血管平滑肌细胞为对照组。结果与对照组相比,机械张应变增加细胞中蛋白激酶B磷酸化水平,促进血管平滑肌细胞的迁移;PI3K的特异性抑制剂Wortmannin抑制张应变诱导的蛋白激酶B的磷酸化,降低了血管平滑肌细胞迁移能力。结论机械张应变通过上调蛋白激酶B磷酸化水平促进了血管平滑肌细胞迁移,提示蛋白激酶B信号通路参与机械张应变条件下血管平滑肌细胞迁移过程的信号传导。     

周期性应变对血管平滑肌细胞生长的影响

为研究周期性应变对VSMCs生长的确切作用,我们利用脉动膜式张应力系统,给VSMCs施加8%,1 Hz和14%,1 Hz两种不同条件的周期性应变.用细胞计数的方法观察VSMCs的生长曲线,用3HTdR掺入率测定法检测VSMCs的DNA合成变化.结果发现8%,1Hz的周期性应变抑制VSMCs生长和DNA合成;14%,1 Hz的周期性应变VSMCs生长和DNA的合成明显增加,24 h和48 h其DNA合成分别是对照组的1.4和1.8倍.结果表明近生理条件下的周期性应变抑制VSMCs的生长,超生理范围的应变促进VSMCs的生长.     

生理性周期性张应变通过激活AMPK磷酸化抑制血管平滑肌细胞迁移

目的 探讨细胞能量代谢的关键调节因子 AMP激活的蛋白激酶AMPK在血管平滑肌细胞（vascular smooth muscle cells, VSMCs）响应生理性周期性张应变力学刺激后对VSMCs迁移的影响。方法 采用 Flexcell-5000T体外细胞张应变加载系统,对大鼠原代培养的 VSMCs 施加10%幅度、1.25 Hz 频率的周期性张应变,模拟VSMCs在体内的生理性力学环境;以未加载周期性张应变的静态细胞为对照组,Western blotting 检测 VSMCs的 p-AMPK蛋白表达;划痕实验检测 VSMCs 迁移功能。结果 与静态组的细胞相比,生理性周期性张应变加载24 h后显著减少划痕愈合面积,提示生理性周期性张应变抑制VSMCs迁移;生理性周期性张应变加载3 h后,VSMCs的p-AMPK蛋白表达显著升高,而加载24 h后p-AMPK蛋白表达显著降低。在生理性周期性张应变加载条件下,孵育AMPK抑制剂可以在张应变加载3 h后显著降低 p-AMPK蛋白表达,而在张应变加载24 h后显著促进VSMCs迁移;在静态条件下孵育AMPK激活剂 AICAR 3 h后显著诱导p-AMPK蛋白表达,孵育24 h后显著抑制VSMCs迁移;提示p-AMPK蛋白表达参与调控VSMCs迁移。结论 生理性周期性张应变能通过激活p-AMPK蛋白表达,进而抑制VSMCs迁移,提示生理性周期性张应变调控VSMCs迁移对维持血管稳态具有重要意义。     

生理性张应变通过增加核骨架蛋白Emerin表达抑制血管平滑肌细胞凋亡

目的探讨细胞核骨架蛋白Emerin及其调控的转录因子在感受张应变力学刺激影响血管平滑肌细胞(vascular smooth muscle cells,VSMCs)凋亡中的作用。方法应用FX-5000T张应变加载系统,对体外培养的VSMCs施加5%幅度、1.25 Hz频率生理性张应变,以静止组为对照;应用cleaved-caspase3 ELISA试剂盒检测VSMCs凋亡水平,Western blotting检测VSMCs细胞核骨架蛋白Emerin蛋白表达水平。静态条件下,RNA干扰抑制VSMCs的Emerin表达,Protein/DNA芯片检测345种转录因子活性;将特异性干扰Emerin后活性发生明显变化(上调或下调超过2倍)的转录因子进行IPA(Ingenurity Pathway Analysis)信息学分析,筛选与凋亡功能相关的转录因子;染色质免疫共沉淀(chromatin immunoprecipitation,CHIP)结合q PCR检测特异性干扰Emerin对其与两种转录因子motif区域结合能力的影响。结果与静止组相比,5%生理性张应变加载24 h后,VSMCs凋亡水平显著降低,提示生理性张应变对细胞具有保护作用;5%张应变作用6、12和24 h均显著增加VSMCs的Emerin表达水平。静态条件下RNA干扰抑制Emerin表达,VSMCs凋亡水平显著增加,且10种参与细胞凋亡功能调控的转录因子活性显著上调(2倍以上),包括CREB-BP1、p300、p55、MAX、NRF-1、STAT1、STAT3、TEF1、TR和BZP;CHIP-q PCR结果显示,Emerin特异性干扰可以显著降低Emerin与STAT家族的两个成员STAT1和STAT3的motif区域结合能力。结论生理性张应变可能通过增加核骨架蛋白Emerin表达而调控Emerin与STAT1、STAT3等多种凋亡相关转录因子motif区域结合,进而调控转录因子活性影响VSMCs凋亡。探讨张应变力学刺激调控VSMCs功能的力学生物学分子机制,对揭示血管生理稳态维持和血管病理重建的分子机制具有一定意义。     

周期性应变诱导血管平滑肌细胞桩蛋白和踝蛋白的表达

利用脉动膜式张应力系统,给离体培养的VSMCs施加14%,1 Hz的周期性应变,免疫荧光细胞化学染色,激光共聚焦扫描显微镜观察、分析桩蛋白和踝蛋白的表达变化.结果表明,周期性应变促进VSMCs桩蛋白和踝蛋白的表达增加.说明桩蛋白和踝蛋白是周期性应变条件下VSMCs细胞内信号传递的重要信号物质.     

淫羊藿苷对大鼠血管平滑肌细胞钙化的抑制作用

目的:研究淫羊藿苷(Icariin)对大鼠血管平滑肌细胞(VSMCs)钙化的抑制作用。方法:组织贴壁法培养大鼠胸主动脉VSMCs,取5-8代细胞分为对照组、钙化模型组和淫羊藿苷干预A、B、C组。对照组用DMEM培养基培养;钙化模型组用含10mmol/Lβ-甘油磷酸盐(β-GP)的DMEM培养基培养;干预A、B、C组均以钙化模型组为基础分别与10-6 mol/L、10-5 mol/L和10-4 mol/L Icariin的DMEM培养基共培养,茜素红-S染色法鉴定各组细胞钙化情况,硝基苯酚法测定各组细胞碱性磷酸酶(ALP)活性,RT-PCR检测各组细胞内骨保护素(OPG)和核因子κB(NF-κB)受体活化因子配体(RANKL)的mRNA水平,用Western blotting检测各组细胞OPG和RANKL的蛋白表达。结果:与对照组比较,钙化模型组VSMCs发生细胞钙化,并形成红色结节,ALP活性显著升高(P0.01),OPG、RANKL mRNA和蛋白表达均增加(P0.01);与钙化模型组比较,干预A、B、C组细胞钙化减少,ALP活性减低(P0.01),OPG、RANKL mRNA和蛋白表达均下调(P0.01),尤以干预B组效果最显著。结论:淫羊藿苷可能通过降低ALP活性及OPG、RANKL表达来抑制动脉钙化。     

Strain Rate Mechanotransduction in Aligned Human Vascular Smooth Muscle Cells

Vascular smooth muscle cells (VSMCs) exist in a dynamic mechanical environment and can sense and respond to mechanical stimuli in vivo. Stretch is known to stimulate intracellular biochemical events, but the influence of the rate at which stretch is applied has not been extensively investigated. Also, most studies of VSMC mechanotransduction use cell culture models not aligned in the direction of stretch. We aligned human VSMC in the direction of uniaxial stretch to examine the importance of strain rate and cell orientation. We demonstrate strain rate profoundly affects stretch-induced phosphorylation of extracellular signal-regulated kinase (ERK)1/2. Low strain rate induced dephosphorylation while physiologic and high rates increased phosphorylation. Dephosphorylation at low strain rate was dependent on cell orientation matching the strain field. Pretreatment with GDPS indicated G proteins are required for ERK1/2 phosphorylation at physiologic strain rate. Apyrase addition to scavenge extracellular ATP inhibited ERK1/2 regulation at low and physiologic strain rates. These results indicate strain rate and cell orientation are important components of mechanotransduction. © 2003 Biomedical Engineering Society. PAC2003: 8719Rr, 8719Ff, 8717-d     

脱细胞血管组织基质的制备和平滑肌细胞的种植

目的组织工程血管的研制成功将为先天性心脏病外科提供一种新的理想的修补材料,本文研究血管脱细胞组织基质的制备,平滑肌细胞的体外培养和种植方法.方法取成年羊胸主动脉,用胰酶消化去除细胞成分,保存弹性蛋白和胶原蛋白,获得血管脱细胞组织基质,经点状注射法,种植体外培养的小牛平滑肌细胞.结果羊主动脉经脱细胞处理,得到的组织基质最大负载下降20%,最大伸长无显著改变;脱细胞组织基质的胶原蛋白含量与新鲜主动脉相似;基质的纤维结构完整,为网状或多孔状;种植的小牛平滑肌细胞生长良好.结论采用多步骤方法获得的血管脱细胞组织基质可用作为制备组织工程血管的支架,适宜于血管平滑肌细胞的生长.     

串珠素对大鼠平滑肌细胞增殖的影响及其机制的研究

目的 观察串珠素对于大鼠血管平滑肌细胞（vascular smooth muscle cells。VSMCs）增殖反应的影响以及细胞信号转导机制。方法以^3H-TdR掺人法测定VSMCs增殖。Westem blot方法检测FAK表达。结果 Perlecan加强碱性成纤维细胞生长因子（basic fibroblast growth factor,bFGF）引起的VSMCs增殖反应，并诱导粘着斑激酶（focal adhesion kinase，FAK）表达上调。Perlecan抗体消除Perlecan促进bFGF致VSMCs增殖反应，并抑制FAK表达。结论 串珠素增强bFGF致大鼠平滑肌细胞的增殖反应，其机制涉及FAK表达上调。     

Effect of Amplitude and Frequency of Cyclic Tensile Strain on the Inhibition of MMP-1 mRNA Expression in Tendon Cells: An In Vitro Study

To determine the effect of cyclic strain amplitude and frequency on MMP-1 (interstitial collagenase) expression in tendon cells, rat tail tendons (RTT) were immobilized or cyclically displaced to various amplitudes (1, 3, or 6% strain at 0.017 Hz) or frequencies (1% strain at 0.017, 0.17, or 1.0 Hz) for 24 hr. Stress-deprivation for 24 hr resulted in a marked upregulation in MMP-1 expression. Cyclic tensile loading at 0.017 Hz was found to significantly inhibit, but not completely eliminate, MMP-1 expression at 1% strain. MMP-1 expression was completely eliminated at 3 and 6% strain. Increasing the frequency of application of the 1% strain to 0.17 or 1.0 Hz completely eliminated MMP-1 expression. Disruption of the actin cytoskeleton with cytochalasin D abolished all inhibitory effects of cyclic strain on MMP-1 expression. The results of our study demonstrate that MMP-1 expression in tendon cells can be modulated by varying amplitudes and frequencies of cyclic tensile strain, presumably through a cytoskeletally based mechanotransduction pathway.     

Anti-Proliferative Effects of Rutin on OLETF Rat Vascular Smooth Muscle Cells Stimulated by Glucose Variability

PurposeProliferation of vascular smooth muscle cells (VSMCs) plays a crucial role in atherosclerosis. Rutin is a major representative of the flavonol subclass of flavonoids and has various pharmacological activities. Currently, data are lacking regarding its effects on VSMC proliferation induced by intermittent hyperglycemia. Here, we demonstrate the effects of rutin on VSMC proliferation and migration according to fluctuating glucose levels.ResultsWe found enhanced proliferation and migration of VSMCs when cells were incubated in intermittent high glucose conditions, compared to normal glucose. These effects were lowered upon rutin treatment. Intermittent treatment with high glucose for 72 h increased the expression of phospho-p44/42 MAPK (extracellular signal regulated kinase 1/2, ERK1/2), phospho-MEK1/2, phospho-PI3K, phospho-NF-κB, phospho-BMK1, and ROS, compared to treatment with normal glucose. These effects were suppressed by rutin. Phospho-p38 MAPK, phospho-Akt, JNK, and apoptotic pathways [B-cell lymphoma (Bcl)-xL, Bcl-2, phospho-Bad, and caspase-3] were not affected by fluctuations in glucose levels.ConclusionFluctuating glucose levels increased proliferation and migration of OLETF rat VSMCs via MAPK (ERK1/2), BMK1, PI3K, and NF-κB pathways. These effects were inhibited by the antioxidant rutin.     

Role of Rac and Rho-GDI Alpha in the Frequency-dependent Expression of h1-calponin in Vascular Smooth Muscle Cells under Cyclic Mechanical Strain

Phenotype transformation of vascular smooth muscle cells (VSMCs) has been reported to be directly influenced by the frequency of mechanical strain. This study explored the effects of different frequencies of mechanical strain on expression of phenotype marker h1-calponin and the possible mechanism. VSMCs were subjected to cyclic strains of 10% elongation at 1 and 2 Hz for 24 h by using a Flexercell strain unit. The protein expression of h1-calponin was assessed by Western blotting and the possible protein kinases involved were evaluated by their specific inhibitor or targeted siRNA ‘knock-down.’ The results showed that cyclic strains modulated the expressions of h1-calponin, phospho-p38, Rac and Rho-guanine nucleotide dissociation inhibitor alpha (Rho-GDIα) in nonlinear frequency-dependent manners. This nonlinear frequency-dependent change of h1-calponin expression could be blocked by a specific p38 inhibitor, SB202190. The changed expression of phospho-p38 induced by the frequencies of cyclic strain was reversed by targeted siRNA ‘knock-down’ of Rac, while enhanced by targeted siRNA ‘knock-down’ of Rho-GDIα. These results suggest that the frequency-dependent expression of h1-calponin under cyclic strain is mediated at least partly by the regulation of Rac and Rho-GDIα expression on the activation of p38 pathway. Ming-Juan Qu and Bo Liu contributed equally to this work.