胰岛素和胰岛素样生长因子-Ⅰ对成骨细胞葡萄糖载体-1表达的影响

Effects of insulin and insulin-like growth factor Ⅰon the expression of glucose transporter 1 of osteoblast

目的:研究胰岛素和胰岛素样生长因子-Ⅰ(IGF-Ⅰ)在高浓度葡萄糖条件下对新生大鼠颅骨成骨细胞葡萄糖载体-1(GLUT1)表达的影响,探讨胰岛素和IGF-Ⅰ对糖尿病性骨质疏松和骨质减少治疗的作用机制。方法:采用组织块法分离培养新生SD仔鼠颅骨成骨细胞,分别给予不同葡萄糖浓度的培养液,即正常浓度葡萄糖(5.5mmol/L)和高浓度葡萄糖(25.5mmol/L)。在高糖条件下分别加入胰岛素(10-6mmol/L)和IGF-Ⅰ(10-7mmol/L)。RT-PCR检测GLUT1mRNA的表达,免疫荧光和WesternBlot检测GLUT1蛋白的表达。结果:与正常浓度葡萄糖组相比,高浓度葡萄糖使成骨细胞GLUT1mRNA和蛋白的表达分别增加51%和35%。胰岛素和IGF-Ⅰ可以下调高糖条件下增加的GLUT1mRNA和蛋白表达,其表达水平与正常浓度葡萄糖条件下的表达水平相似。结论:胰岛素和IGF-Ⅰ纠正了高浓度葡萄糖引起的成骨细胞GLUT1表达的改变可能是治疗糖尿病性骨质疏松和骨质减少的机制之一。

Objective To investigate the effects of insulin and insulin-like growth factor Ⅰ （IGF-Ⅰ） on the expression of glucose transporter 1 （GLUT1） of osteoblasts in high glucose concentration and to explore the therapeutic mechanism of insulin and IGF-Ⅰ for diabetic osteoporosis and osteopenia. Methods Osteoblasts from new born Sprague-Dawley rats were isolated and cultured in media containing either normal （5.5 mmol/L） or high glucose concentration （25.5 mmol/L）, respectively administering insulin （10^-6mmol/L） and IGF-Ⅰ （10^-7mmol/L）. The level of GLUT1 mRNA was determined by semiquantitativc reverse transcription-PCR. The GLUT1 protein was detected by immunofluorescence and Western Blot. Results The gray scale showed the levels of GLUT1 mRNA and protein in the high glucose group increased 51% and 35% respectively, compared with the levels of their counterparts in the normal glucose group. However, IGF-Ⅰ and insulin could lower the levels of GLUT1 mRNA and protein in the high glucose group. Conclusions The present study showed that insulin and IGF-Ⅰ rectified the change of the expression of GLUT1 mRNA and protein caused by increased level of glucose, which may be involved in the therapeutic mechanism of diabetic osteoporosis and osteopenia.