MIR-21在周期性张应变诱导大鼠血管平滑肌细胞细胞外基质表达中的作用及其机制

发布时间：2018-03-15 18:27

本文选题：周期性张应变　切入点：血管平滑肌细胞　出处：《上海交通大学》2012年硕士论文　论文类型：学位论文

【摘要】：血管重建(remodeling)是高血压、动脉粥样硬化等心血管疾病共同的发病基础和基本的病理过程。力学因素在血管重建中起着重要作用。高血压血管重建的主要特征之一是血管承受的周向张应变(应力)升高,细胞外基质(extracellular matrix,ECM)成分表达异常,导致血管纤维化。可见,周期性血管的周向张应变与高血压血管重建的发生和发展密切相关。因此,研究张应变影响血管壁细胞外基质表达的调控机制,对于寻找高血压血管重建的防治措施具有重要的理论和临床意义。本研究复制了腹主动脉缩窄制作大鼠高血压动物模型,以正常血压(假手术组)大鼠为对照,探讨高血压状态下,胸主动脉细胞外基质的变化。同时,模拟高血压在体动脉承受的张应变状态,用Flexercell细胞张应变加载系统对大鼠血管平滑肌细胞(vascular smooth muscle cells, VSMCs)施加周期性张应变,加载条件为:频率统一为1.25 Hz,幅度分别为0(正常静态)、5%(正常血压状态)和15%(高血压状态),加载时间均为12 h。然后,大鼠各组主动脉组织和各组VSMCs,用Western blotting、Real time RT-PCR技术检测ECM,包括I型胶原、III型胶原、弹性蛋白和miR-21的表达。用miR-21抑制因子(inhibitor)抑制VSMCs的miR-21表达,以探讨miR-21是否参与周期性张应变诱导大鼠VSMCs细胞外基质的调控。结果显示:①与假手术组相比,术后2W组动物胸主动脉的ECM和miR-21的表达显著上升;术后4W动物胸主动脉的I型胶原、III型胶原和miR-21表达显著上升,弹性蛋白表达下降非常显著;②与静态组和5%张应变组相比,15%张应变组VSMCs的I型胶原表达无显著性差异,III型胶原表达显著升高,弹性蛋白和Smad7表达显著下降。张应变加载组VSMCs的miR-21表达均明显上调;③抑制miR-21表达,降低了周期性张应变条件下VSMCs的III型胶原蛋白水平表达,上调了miR-21预测靶蛋白Smad7的表达。上述结果表明,高血压状态下,胸主动脉ECM表达异常,导致动脉顺应性明显下降。病理性周期性张应变也诱导了VSMCs的ECM异常表达。在病理性周期性张应变作用下,miR-21表达上调,其下游靶蛋白Smad7表达下调,血管胶原蛋白表达增加,提示Smad7可能通过参与血管胶原蛋白表达调控,进而参与了对血管纤维化的负调控;Smad7有可能成为治疗血管纤维化的一个新靶标。
[Abstract]:Vascular remodeling is hypertension, The common pathogenesis and basic pathological process of cardiovascular diseases such as atherosclerosis. Mechanical factors play an important role in vascular remodeling. One of the main characteristics of vascular remodeling in hypertension is the increased circumferential tensile strain (stress) of blood vessels. The abnormal expression of extracellular matrix ECM leads to vascular fibrosis. It can be seen that the circumferential strain of periodic blood vessels is closely related to the occurrence and development of vascular remodeling in hypertension. It is of great theoretical and clinical significance to study the regulation mechanism of tension strain on the expression of extracellular matrix in vascular wall. In this study, a rat model of hypertension was established by coarctation of abdominal aorta. The changes of extracellular matrix of thoracic aorta were studied in rats with normal blood pressure (sham operation group) as control. The tension strain of vascular smooth muscle cells (VSMC s) in vascular smooth muscle cells (VSMC) of rats was subjected to cyclic strain by Flexercell cell strain loading system. The loading conditions are as follows: the frequency is 1. 25 Hz, the amplitude is 0 (normal static state of blood pressure) and the loading time is 12 hours. The expression of Western blotting real time RT-PCR, including type I collagen III, elastin and miR-21, was detected by Western blotting real time RT-PCR in aorta and VSMC of rats. The miR-21 expression of VSMCs was inhibited by miR-21 inhibitor. To investigate whether miR-21 is involved in the regulation of extracellular matrix of rat VSMCs induced by cyclic tensile strain. The results showed that the expression of ECM and miR-21 in thoracic aorta increased significantly in 2 W group compared with that in sham operation group, and the expression of type I collagen III and miR-21 in thoracic aorta of 4 W group increased significantly 4 W after operation. There was no significant difference in the expression of type I collagen in VSMCs of 15% strain group compared with static group and 5% strain group. The expression of VSMCs miR-21 in tension-strain loading group was significantly decreased, and the expression of III type collagen in VSMCs was decreased under cyclic tension strain, and the expression of miR-21 predictive target protein Smad7 was up-regulated in the group of tension-strain loading, which inhibited the expression of miR-21, decreased the expression of III type collagen protein in VSMCs under cyclic tension strain, and up-regulated the expression of miR-21 predictive target protein Smad7. These results indicate that abnormal expression of ECM in thoracic aorta leads to a decrease in arterial compliance under hypertension. Pathological cyclic tension strain also induces abnormal expression of ECM in VSMCs. The expression of miR-21 is upregulated under the action of pathological cyclic tension strain. The downstream target protein Smad7 expression was down-regulated and the vascular collagen protein expression increased, suggesting that Smad7 may be involved in the regulation of vascular collagen protein expression. Therefore, Smad7 may be a new target for the treatment of vascular fibrosis.
【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R363

【共引文献】