铅诱导小鼠血管平滑肌细胞去分化作用体外研究

An in vitro study of the impact of lead on dedifferentiation of mouse vascular smooth muscle cells

  • 摘要:
    目的 探究体外铅暴露在血管平滑肌细胞(VSMC)表型转化中的作用,为揭示铅暴露导致血管病变发生机制提供新依据。
    方法 将小鼠主动脉平滑肌细胞系(MOVAS)细胞分为对照组(0 µmol·L-1)和不同铅诱导处理组[低浓度组(0.1、1、5、10 µmol·L-1)、高度浓度组(15、25、50 µmol·L-1)],采用MTT法测定各组细胞的增殖能力,通过细胞划痕实验观察各组细胞的迁移能力,通过荧光定量聚合酶链反应测定VSMC收缩型标志物相关基因平滑肌肌动蛋白α(α⁃SMA)、平滑肌肌动蛋白结合蛋白(SM22α)及合成表型相关基因骨桥蛋白(OPN)、基质金属蛋白酶9(MMP9)的mRNA水平和转录因子SOX9的表达水平,通过免疫印迹法测定α⁃SMA、OPN、MMP9蛋白表达水平。
    结果 在0~50 μmol·L-1铅离子浓度下,MOVAS细胞出现增殖现象,其中5~50 μmol·L-1组的细胞增殖能力高于对照组(均P<0.05)。在0~10 μmol·L-1铅离子浓度下,细胞迁移能力逐渐增强,其中5 μmol·L-1组(q=4.574,P=0.003)和10 μmol·L-1组(q=10.570,P<0.001)细胞迁移能力高于对照组。与对照组相比,10 μmol·L-1组血管平滑肌收缩表型基因α⁃SMAq=7.426,P<0.001)和SM22α(q=4.766,P=0.001)的mRNA相对表达水平降低,OPNq=11.330,P<0.001)、MMP9(q=7.842,P<0.001)、SOX9(q=11.120,P<0.001)基因的mRNA相对表达水平升高;与对照组相比,10 μmol·L-1组血管平滑肌收缩表型标志物α⁃SMA蛋白的相对表达水平降低降低(q=2.897, P=0.049),合成型标志物OPN(q=3.188,P=0.031)、MMP9(q=3.292,P=0.026)蛋白的相对表达水平升高。
    结论 铅体外诱导能够诱导VSMC从收缩表型去分化为合成表型,提示一定剂量的铅暴露可能引起心血管系统的不良变化。

     

    Abstract:
    Objective To explore the role of lead exposure in the phenotypic transformation of vascular smooth muscle cells (VSMC), and to provide new insights for the mechanism of lead impact on vascular lesions.
    Methods Mouse aortic smooth muscle cells (MOVAS) were divided into a control group (0 μmol·L-1), low concentration lead groups (0.1, 1, 5, and 10 μmol·L-1), and high concentration lead groups (15, 25, and 50 μmol·L-1). MTT assays were used to assess the proliferation of the cells, and scratch assays were implicated to measure migration ability of the cells. Fluorescence quantitative PCR was employed to determine levels of mRNA expression for smooth muscle actin α (α⁃SMA), smooth muscle 22 alpha (SM22α), synthetic phenotype-related genes osteopontin (OPN), matrix metalloproteinase 9 (MMP9), and the transcription factor SOX9. Immunoblotting was used to determine levels of protein expression for α-SMA, OPN, and MMP9.
    Results Proliferation of MOVAS was observed under the lead ions concentrations of 0‒50 µmol·L-1, with a significant increase of proliferation compared to the control group at the concentrations of 5‒50 µmol·L-1 (all P<0.05). The migration ability of cells gradually increased at the concentrations of 0‒10 µmol·L-1, with a significant increase at 5 (q=4.574, P=0.003) and 10 µmol·L-1 (q=10.570, P<0.001) compared to the control group. The 10 µmol·L-1 lead ions significantly reduced the levels of mRNA expression for vascular smooth muscle contractile phenotype genes α⁃SMA (q=7.426, P<0.001) and SM22α (q=4.766, P=0.001), while significantly increasing the levels of mRNA expression for OPN (q=11.330, P<0.001), MMP9 (q=7.842, P<0.001), and SOX9 (q=11.120, P<0.001) genes. Furthermore, the 10 µmol·L-1 lead ions significantly reduced the levels of protein expression for the vascular smooth muscle contractile phenotype marker α-SMA protein (q=2.897, P=0.049), while significantly increasing the levels of protein expression for the synthetic markers OPN (q=3.188, P=0.031) and MMP9 (q=3.292, P=0.026), compared to the control group.
    Conclusion Treatment with lead in vitro induced VSMC to differentiate from contractile phenotype to synthetic phenotype, indicating that a certain dose of lead exposure might be detrimental to the cardiovascular system.

     

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