【摘要】 【目的】研究胰岛素对生长期长骨成骨细胞增殖影响及受体后作用机制。【方法】用四唑蓝比色法和蛋白质免疫印迹法观察不同浓度胰岛素对成骨细胞增殖和胞内P44/42MAPK及其磷酸化的变化。【结果】胰岛素对成骨细胞的促增殖作用具浓度和时间依赖性,10-7mol/L时促增殖作用最强,96h后细胞增殖进入平台期。用不同浓度胰岛素急性刺激成骨细胞各组的P44/42MAPK表达量差别无统计学意义(P>0.05),但P44/42MAPK磷酸化程度随加入胰岛素浓度的增高而增强(组间P<0.05);经胰岛素慢性处理后的各组的P44/42MAPK表达量仍差别无统计学意义(P>0.05),但P44/42MAPK磷酸化程度却随着胰岛素浓度的升高而呈逐渐下降趋势(组间P<0.05)。【结论】胰岛素能以生长因子样的作用呈剂量依赖性的方式刺激成骨细胞生长,但高胰岛素状态以及长时间的胰岛素作用后此种增强效应消失。其受体酪氨酸蛋白激酶介导的MAPK信号途径参与了促成骨细胞的生长增殖的作用。更多还原

【Abstract】 Objective]To study the effects of insulin on proliferation of osteoblast and the relationship between insulin post-receptor P44/42MAPK change in osteoblast and osteoblastic cell growth.[Methods]The effects of different levels of insulin on osteoblast in different time were assessed by MTT colorimetry and the determination of the protein level and phosphorylated protein of P44/42MAPK by Western blot analysis.[Results] Insulin enhanced the proliferation of the osteoblast, depending on its dose and time exposure. 10-7mol/L insulin showed the strongest effect. When the insulin concentration beyond 10-7mol/L and the time beyond 96 h, the action attained the plateau phase. Insulin stimulation for 10 min rapidly induced the activity of tyrosine phosphorylation of P44/42MAPK. The degree of tyrosine phosphorylation of P44/42MAPK was increasing step by step along with the dose of insulin increase from 0 to 10-7 mol/L (P < 0.05, between the groups). After 10-7mol/L insulin treatment for 16 h, there was a marked reduction in the tyrosine phosphorylation of P44/42 MAPK(P< 0.05, between groups). There were no significant changes in protein level of P44/42MAPK. [Conclusion] Insulin can enhance the proliferation of osteoblast as a growth factor in a suitable concentration, but this effect disappeared at chronic high insulin stimulation. The MAPK may be involved in the proliferating effect of insulin on osteoblast. Transient stimulation of insulin can active the P44/42 MAPK, however chronic high insulin stimulation to osteoblast results in down-regulation of P44/42MAPK signal activity.更多还原