TGF-β1在雷奈酸锶促进大鼠骨髓间充质干细胞向成骨细胞分化中的作用

Role of TGF-β_1 in strontium ranelate-induced osteogenic differentiation of rat bone marrow mesenchymal stem cells

目的:探讨转化生长因子β1(TGF-β1)在雷奈酸锶(Sr)促进大鼠骨髓间充质干细胞(rBMSCs)向成骨细胞分化中的作用。方法:应用试剂盒测定碱性磷酸酶(ALP)活性及钙结节数量;Western blotting法测定TGF-β1的表达水平。结果:应用0.1、1、3、5、及7 mmol/L Sr分别处理rBMSCs 7 d,均能明显增加ALP活性,其中3 mmol/L Sr增加ALP活性的作用最大(P<0.01)。3 mmol/L Sr作用rBMSCs 21 d可明显增加钙结节数量。应用0.1～5 mmol/L Sr分别处理rBMSCs 7 d,可显著地上调TGF-β1的表达,其中浓度为1 mmol/L时,TGF-β1表达达到高峰。1～7 d,1 mmol/L Sr呈时间依赖性地促进TGF-β1表达。1 mmol/L Sr处理rBMSCs前2 h,给予TGF-β1抑制剂SB431542预处理,不仅可明显地抑制Sr对TGF-β1表达的上调作用,而且显著地减弱Sr对ALP活性及钙结节形成的促进作用。结论:Sr可通过上调TGF-β1表达促进rBMSCs向成骨细胞分化。

AIM： To study the role of transforming growth factor β1（TGF-β1） in strontium ranelate（Sr）-induced osteogenic differentiation of rat bone marrow mesenchymal stem cells（rBMSCs）.METHODS： The activity of alkaline phosphatase（ALP） and the number of calcium nodules were detected by commercial kits.The expression of TGF-β1 was detected by Western blotting.RESULTS： Exposure of rBMSCs to Sr at the concentrations from 0.1 mmol/L to 7 mmol/L for 7 days obviously increased activity of ALP.When the concentration of Sr was up to 3 mmol/L,the activity of ALP reached to the highest level（P0.01）.Treatment of rBMSCs with Sr at the same concentration for 21 days also significantly increased the number of calcium nodules.When rBMSCs were treated with Sr at 0.1 mmol/L to 5 mmol/L for 7 days,the expression of TGF-β1 z was enhanced obviously.When the concentration of Sr was up to 1 mmol/L,the expression of TGF-β1 reached to maximum.For 1 to 7 days,1 mmol/L Sr time-dependently increased the expression of TGF-β1.Pretreatment of rBMSCs with SB431542,an inhibitor of TGF-β1,for 2 h,prior to exposure to Sr（1 mmol/L）,inhibited not only Sr-induced overexpression of TGF-β1,but also the activity of ALP and the number of calcium nodules.CONCLUSION： Sr promotes rBMSCs differentiating into osteoblasts by up-regulating the expression of TGF-β1.