胰岛素样生长因子-1保护人终板软骨细胞的作用机制

Mechanism of Protective Role of Insulin Growth Factor-1 in Human Endplate Chondrocytes

目的:明确胰岛素样生长因子-1(IGF-1)保护人终板软骨细胞的作用机制。方法:从腰椎爆裂性骨折患者的终板分离原代终板软骨细胞,用IGF-1刺激原代终板软骨细胞,检测COL2A1,SOX9和MMP13的mRNA水平和蛋白表达水平;用IGF-1刺激原代终板软骨细胞,检测PI3K活性、AKT和p-AKT蛋白表达,以及ERK1/2和p-ERK1/2的蛋白表达;IGF-1联合PI3K抑制剂LY 294002或ERK1/2抑制剂AG-126处理原代终板软骨细胞,再次检测COL2A1,SOX9和MMP13的蛋白表达,明确其上下游关系。结果:IGF-1可以诱导COL2A1和SOX9上调表达,并抑制MMP13;此外,IGF-1增高PI3K活性,并上调p-AKT和p-ERK1/2;IGF-1上调COL2A1的作用依赖于PI3K-AKT信号通路的激活,而IGF-1诱导SOX9上调和MMP13下调依赖于ERK1/2的活化。结论:IGF-1激活PI3K-AKT信号通路和ERK1/2通路,调节终板软骨细胞功能性蛋白的表达,为椎间盘退变的治疗提供理论依据。

Objective:To identify the underlying mechanism of protective role of insulin growth factor-1(IGF-1) in endplate chondrocytes. Methods:Primary endplate chondrocytes were isolated from the endplate of patients with lumber burst fracture. The cells were treated with IGF-1 followed by detecting the expression of COL2 A1,SOX9 and matrix metallopeptidase 13(MMP13),as well as the activity of phophatidylinositol 3 kinase(PI3 K) and the expression of AKT,p-AKT,extracellular signal-regulated kinase 1/2(ERK1/2) and p-ERK1/2. Next,we treated the cells with PI3 K inhibitor LY 294002 or ERK1/2 inhibitor AG-126 in the presence of IGF-1 to explore the underlying mechanism. Results:IGF-1 induced upregulation of COL2 A1 and SOX9 and downregulation of MMP13 in primary endplate chondrocytes. In addition,IGF-1 could activate PI3 K-AKT signaling pathway and ERK1/2. Further investigation revealed that IGF-1-induced upregulation of COL2 A1 depended on PI3 K-AKT signaling pathway,while IGF-1-induced activation of ERK1/2 was responsible for the upregulation of SOX9 and downregulation of MMP13 in primary endplate chondrocytes. Conclusion:Activation of PI3 K-AKT and ERK1/2 by IGF-1 may involve in the expression of functional proteins in endplate chondrocytes,providing a theoretical basis for treatment of intervertebral disc degeneration.