The interaction of IGF and IGF-binding proteins in repairing of cartilage tissue

胰岛素样生长因子-I（IGF-I）是软骨组织的重要合成代谢因子，其作用部分受胰岛素样生长因子结合蛋白（IGFBPs）调节。本研究的目的是调查IGFBPs对IGF-I的行动和IGF-I的结合细胞使用可重复的永生化的人软骨细胞培养模型的影响。在无血清培养基中用IGF-I或des（1-3）IGF-I处理C-28/I2细胞以剂量依赖性方式刺激细胞增殖。然而，des（1-3）IGF-I的作用更强，从而表明内源性产生的IGFBPs抑制IGF作用。IGF-I的刺激作用被IGFBP-3的加入显著抑制。[125 I] IGF-I与细胞的结合被IGFBP-3取代。我们的研究结果表明，IGFBPs之间的平衡，IGF受体结合和其对软骨细胞增殖的作用可能会调节软骨组织修复。

Insulin-like growth factor-I (IGF-I) is an important anabolic factor for cartilage tissue and its action is in part regulated by IGF-binding proteins (IGFBPs). The object of this study was to investigate the effects of IGFBPs on IGF-I action and on binding of IGF-I to cells using a reproducible immortalized human chondrocyte culture model. Treatment of the C-28/I2 cells with IGF-I or des (1-3 ) IGF-I in serum-free medium stimulated cell proliferation in a dose-dependent manner. However, the effect of des (1-3) IGF-I was more potent, thereby suggesting that endogenously produced IGFBPs inhibited IGF action. The stimulatory effect of IGF-I was inhibited significantly by addition of IGFBP-3. Binding of [125I] IGF-I to the cells was displaced by IGFBP-3. Our findings indicate that the balance between IGFBPs, IGF receptor binding and its action on chondrocyte proliferation may modulate cartilage tissue repair.