Role of mitochondrial pathway in compression-induced apoptosis of nucleus pulposus cells
Role of mitochondrial pathway in compression-induced apoptosis of nucleus pulposus cells
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DOI：
10.1007/s10495-012-0708-3
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发表时间：
2012-06-01
期刊：
影响因子：
7.2
通讯作者：
Xiong, Li-Ming
中科院分区：
文献类型：
--
作者：
Ding, Fan;Shao, Zeng-Wu;Xiong, Li-Ming
在体内，各种机械应力均可诱导髓核(NP)细胞凋亡和椎间盘退变，但退变IVD中NP细胞数量减少的分子机制尚不清楚。本研究的目的是探讨线粒体途径是否参与压迫诱导的兔NP细胞的凋亡。采用细胞计数试剂盒-8型细胞计数法检测压缩6、12、18、24、36h后1级压力(1.0 Mpa)对细胞存活率的影响。流式细胞仪分析细胞凋亡率，相差显微镜和Hoechst 33258染色观察细胞形态变化。采用实时定量聚合酶链式反应和Western-blotting分别检测细胞凋亡相关基因Bax、Bcl2和Caspase-3的表达。通过分析线粒体通透性转换孔(MPTP)、活性氧(ROS)和线粒体膜电位(MMP)来评价线粒体功能。结果表明，所有时间点的压力均以时间依赖的方式诱导兔NP细胞的凋亡，细胞存活率显著降低。此外，该水平的压迫还严重抑制了线粒体的功能，如MPTP的开放、ROS的过量产生和线粒体膜电位的降低。我们的发现表明，压迫诱导的IVD变性至少部分是通过NP细胞的线粒体凋亡途径介导的。
Various mechanical stresses can induce apoptosis of nucleus pulposus (NP) cells and intervertebral disc (IVD) degeneration in vivo, but the underlying molecular mechanism by which the number of NP cells is decreased in degenerated IVD is still not elucidated. The purpose of this study was to investigate whether the mitochondrial pathway is involved in compression-induced apoptosis of rabbit NP cells. The compression apparatus was used to investigate the effect of the compression in this process at one magnitude (1.0 MPa) for 6, 12, 18, 24 and 36 h. Cell viability was measured by cell counting kit-8. Apoptosis rate was analyzed by flow cytometry and the morphologic changes in apoptosis cells were observed by the phase-contrast microscopy and Hoechst 33258 staining. The apoptosis-related gene and protein synthesis, such as Bax, Bcl-2 and Caspase-3, was analyzed by real-time polymerase chain reaction and Western-blot, respectively. Mitochondrial function was evaluated by analyzing the mitochondrial permeability transition pore (MPTP), as well as reactive oxygen species (ROS) and mitochondrial membrane potential (MMP). The results indicated that compression at the magnitude of all time points induced apoptosis of rabbit NP cells in a time-dependent manner, and the cell viability was reduced significantly. Furthermore, the compression at this level profoundly suppressed the functions of the mitochondria such as the opening of MPTP, the excessive production of ROS and the decreased MMP. Our findings suggest that the compression-induced IVD degeneration is mediated, at least in part, via the mitochondrial apoptotic pathway in NP cells.