【摘要】 探讨力学因素对大鼠骨髓间充质干细胞(MSCs)中基质金属蛋白酶-9(MMP-9)基因表达的影响及可能的信号机制。体外分离培养大鼠骨髓MSCs;利用平行平板流动腔力学加载装置,对细胞进行低(5 dyne/cm2)、中(15dyne/cm2)和高(30 dyne/cm2)不同剪应力的刺激,采用RT-PCR技术分析MMP-9基因的表达;利用Wortmannin(PI3K特异性抑制剂)、SB202190(P38MAPK特异性抑制剂)和PD98059(ERK1/2MAPK特异性抑制剂)信号阻断剂探讨力学信号传导途径。结果显示:(1)MSCs在未受力状态下MMP-9基因的表达较弱,15 dyne/cm2剪应力作用2 h表达即明显增强,24 h达高峰,呈时间依赖;(2)低、中和高剪应力分别刺激2 h,均可使MSCs MMP-9基因表达增强,其中15 dyne/cm2时最强;(3)用三种信号通路的抑制剂预处理后,SB202190组MMP-9基因表达明显被抑制。以上结果表明:剪应力可诱导MSCs中MMP-9基因表达,其表达量与刺激时间和剪应力的强度密切相关,其中p38MAPK信号通路起关键作用。更多还原

【Abstract】 This paper was designed to investigate the effect of laminar shear stress on matrix metalloproteinase-9(MMP-9) expression in rat bone marrow-derived mesenchymal stem cells(MSCs),and the possible signal transduction mechanism involved.Rat bone marrow MSCs were isolated and cultured, then,exposed to laminar shear stress at indicated strengths such as low(5dyne/cm2),medium(15dyne/cm2)and high(30dyne/cm2)via parallel plate flow chamber.RT-PCR was used to analyze the expression of MMP-9.The signaling inhibitors such as Wortmannin(PI3K specific inhabitor),SB202190(p38MAPK specific inhabitor),and PD98059(ERK1/2 specific inhabitor) were used to investigate the possible mechanical signal transduction pathway.The results showed:(1)The expression of MMP-9 was weak in static state,however,MMP-9 expression increased when MSCs were exposed to 15dyne/cm2 shear stress for 2 hours,and MMP-9 expression increased with the extension of stimulating time,and it reached the peak at 24 h;(2) MSCs were stimulated by shear stress for 2 hours at different strengths(5dyne/cm2,15dyne/cm2,30dyne/cm2),and under all these conditions,the expression of MMP-9 increased,and reached the peak at 15 dyne/cm2;(3) After MSCs were pretreated by three kinds of signal pathway inhibitors,the expression of MMP-9 did not change obviously in Wortmannin group and PD98059 group,but it was significantly inhibited in SB202190 group.This study demonstrated that shear stress could induce the expression of MMP-9 in rat bone marrow-derived mesenchymal stem cells;the amount of MMP-9 expression was closely related to stimulating time and the strengths of shear stress;and p38MAPK signal pathway played a critical role during the process.更多还原