不同频率张应变对大鼠血管平滑肌细胞外基质的影响

为研究不同频率张应变对血管平滑肌细胞(VSMC)细胞外基质(ECM)的影响,探讨不同频率张应变与血管重建(remodeling)的关系,本文应用 FX-4000TTM细胞应变加载系统,对体外培养的大鼠VSMC施加10%张应变,频率分别为0.5、1和2 Hz,加载时间为24 h,以未加载张应变的VSMC为对照组.采用Real-time RT-PCR、western blot等技术检测不同频率张应变对fibronectin、collagen I和collagen III表达的影响,以及可能参与调节的蛋白激酶p38的活性变化.结果显示:①张应变频率可以明显影响细胞外基质Fibronectin、collagen I和collagen III的mRNA的表达,其影响效果与频率大小是一种非线性关系;②蛋白激酶p38参与调节了一定频率张应变诱导的ECM的表达变化.结果表明不同频率的张应变可以影响VSMC细胞外基质表达的变化,提示频率的改变可能参与调节细胞外基质的合成与分泌;在应力引起的血管重建中频率的改变可能起着重要的作用.

Effect of Frequency of Cyclic Tensile Strain on Extracellular Matrix of Rat Vascular Smooth Muscle Cells in Vitro

To investigate the effect of different frequencies of cyclic tensile strain on extracellular matrix (ECM) of vascular smooth muscle cells (VSMCs) and to research the relationship between tensile strain and vascular remodeling, the aortic vascular smooth muscle cells of rats grown on dishes coated with collagen I were subjected to 10% elongation and various frequencies of mechanical strain using the Flexercell 4000 Strain Unit. The expression of extracellular matrix including fibronectin, collagen I and collagen III was detected by Real-time RT-PCR, and p38 activity by western blot. The result showed that the expression of extracellular matrix was induced by mechanical strain in a nonlinear frequency-dependent manner, which was mediated by p38 pathway. These results demonstrate that the variety of frequencies of cyclic tensile strain could modulate the expression of ECM. It may have important influence on vascular remodeling.