雷奈酸锶通过上调骨形态发生蛋白2的表达促进骨髓间充质干细胞分化为成骨细胞

目的: 探讨雷奈酸锶(strontium ranelate,Sr)是否可以通过上调骨形态发生蛋白 2(bone morphogenetic protein 2,BMP-2)的表达而促进大鼠骨髓间充质干细胞(bone marrow mesenchymal stem cells,BMSCs)分化为成骨细胞。方法: 对大鼠BMSCs进行分离、纯化、培养及向成骨细胞的定向诱导分化,并在诱导培养时,根据实验目的加入不同浓度Sr以及BMP-2的拮抗剂noggin。用酶标法检测成骨细胞分化和功能成熟的早期标志物——碱性磷酸酶(alkaline phosphatase,ALP)活性的变化,用茜素红染色检测细胞钙化水平,用Western blotting法检测BMP-2蛋白的表达水平。结果: 应用0.1~7 mmol/L Sr处理细胞7 d均可使细胞ALP活性显著增加,其中浓度为3 mmol/L时效果最显著;应用3 mmol/L Sr处理细胞21 d可使细胞钙化结节明显增多;应用0.1~7 mmol/L Sr处理细胞7 d后细胞内BMP-2蛋白水平明显增高;在Sr处理BMSCs前,应用BMP-2拮抗剂noggin预处理细胞2 h不仅抑制Sr对BMP-2表达的上调作用,还拮抗Sr对ALP活性及钙化结节形成的促进作用。结论: 上调BMP-2的表达可能是Sr促进大鼠BMSCs分化为成骨细胞的作用机制之一。

Strontium ranelate promotes differentiation of bone marrow mesenchymal stem cells to osteoblasts by increasing expression of bone morphogenetic protein 2

AIM:To explore whether strontium ranelate(Sr) promotes differentiation of rat bone marrow mesenchymal stem cells(BMSCs) to osteoblasts by increasing the expression of bone morphogenetic protein 2(BMP-2). METHODS:Rat BMSCs were isolated,purified and cultured,then were induced to differentiate into osteoblasts.The cells were treated with different concentrations of Sr or noggin(an inhibitor of BMP-2) according to the experimental purposes. The activity of alkaline phosphatase(ALP) was measured by colorimetry.Mineralized nodules were measured by alizarin red staining.The expression of BMP-2 was detected by Western blotting.RESULTS:Treatment with Sr at concentrations of 0.1 mmol/L to 7 mmol/L for 7 d obviously increased the activity of ALP,and Sr at concentration of 3 mmol/L produced the maximum effect.Exposure of the cells to Sr at concentration of 3 mmol/L for 21 d significantly increased mineralized nodules.Exposure of the cells to Sr at concentrations of 0.1 mmol/L to 7 mmol/L for 7 d markedly increased the expression of BMP-2.Preconditioning with noggin at concentration of 100 u,g/L for 2 h not only inhibited Srinduced expression of BMP-2,but also antagonized the increase in the activity of ALP and mineralization induced by Sr in BMSCs.CONCLUSION:Up-regulation of the expression of BMP-2 may be one of the mechanisms by which Sr promotes differentiation of rat BMSCs to osteoblasts.