不同强度静电磁场对体外培养骨髓间充质干细胞增殖与分化的影响

本实验研究不同强度静电磁场对体外培养大鼠骨髓间充质干细胞增殖与分化作用. 体外分离培养大鼠骨髓间充质干细胞，传代后随机分为6组，分别用强度为0（对照组）、0.9、1.2、1.5、1.8和2.1 mT的静电磁场处理，每d每次处理30 min. 在磁场处理后的9~10 d ,骨髓间充质干细胞开始出现钙化小颗粒. 0.9 mT组抑制骨髓间充质干细胞增殖，1.5到2.1mT组促进骨髓间充质干细胞增殖. 在磁场处理后的12 d和15 d ,1.5和1.8 mT组极显著地增加了碱性磷酸酶(AKP)活性. 采用AKP组织化学染色和钙化结节染色对骨髓间充质干细胞成骨性分化进行鉴定，AKP组织化学染色和钙化结节染色都呈现了极强的阳性结果，尤以1.5 mT和1.8 mT阳性染色面积最大. 在SEMFs处理后的48 h 和96 h ，1.5 mT和1.8 mT组胶原I(collagen-Ⅰ)和骨形态发生蛋白2(bone morphogenetic protein-2, Bmp-2) 基因表达水平显著高于对照组.在SEMFs处理后的12 d, BMP-2蛋白表达量高于对照组. 研究表明,0.9 mT 组抑制骨髓间充质干细胞增殖，1.5 mT到2.1 mT组不同强度静电磁场促进体外培养骨髓间充质干细胞的增殖. 磁场组能促进骨髓间充质干细胞成骨性分化，其中尤以1.5 mT和1.8 mT组促进大鼠骨髓间充质干细胞分化作用效果最为明显.

Proliferation and Differentiation of Rat Bone Marrow Mesenchymal Stem Cells in Static Electromagnetic Fields of Different Intensities in vitro

The study explores the effect of the intensity of static electromagnetic fields (SEMFs) on the proliferation and differentiation of mesenchymal stem cells in vitro. The rat bone marrow mesenchymal stem cells were isolated and divided into 6 groups after one passage, including a control group and others that exposed to different intensities of SEMFs (0.9~2.1 mT with a 0.3 mT interval) for 30 min/time/d. Small calcified nodules were formed after 9 days or 10 days in SEMFs. Compared with the control, the cell proliferation was increased in 1.5, 1.8 and 2.1 mT groups, but decreased in the 0.9 mT group. In the 1.5 and 1.8 mT groups, the alkaline phosphatase (AKP) activity of was significantly increased after 12 and 15 days as shown also by histochemistry staining with alizarin red in calcified nodules. The collagen-Ⅰand Bmp-2 mRNA expression levels after 48 and 96 hours were increased, as well as the BMP-2 protein tested by Western blotting. Our study showed that SEMFs promoted osteogenic differentiation of rat bone marrow mesenchymal stem cell during the mineralization stage, especially in 1.5 and 1.8 mT.