不同干预时间正弦电磁场对大鼠骨髓基质干细胞成骨性分化的影响

Effects of sinusoidal electromagnetic fields on osteoblastic differentiation of rats bone marrow mesenchymal stem cells at different treatment time

目的:研究不同治疗时间正弦电磁场(50 Hz,1.8 mT)对体外培养大鼠骨髓间充质干细胞成骨性分化的影响,筛选出最佳临床治疗时间。方法:采用贴壁筛选法培养原代大鼠骨髓间充质干细胞,每天在频率为50 Hz,强度为1.8 mT的磁场环境中处理0.5 h、1.0 h、1.5 h、2.0 h和2.5 h;同时设立未经电磁场处理的细胞作为对照组。于处理后的第3 d、6 d、9 d和12 d分别测定细胞碱性磷酸酶活性、骨钙素分泌量、钙化结节数以及Ⅰ型胶原表达量,并比较各组间差异;于处理后12 h提取细胞总RNA,用RT Real-TimePCR法检测成骨性分化基因Osterix表达情况。结果:正弦电磁场干预1.0 h能明显促进骨髓间充质干细胞的成骨性分化,表现在该组的碱性磷酸酶活性、骨钙素分泌量、钙化结节数、I型胶原表达量以及成骨性分化基因的表达量最高,亦显著高于对照组(P<0.05)。结论:50Hz、1.8mT强度的正弦电磁场能促进骨髓间充质干细胞的成骨性分化,以作用1.0 h成骨效果最为明显。

Objective：To investigate the effect of sinusoidal electromagnetic fields（SEMF） on osteogenic differentiation of ratbone marrow mesenchymal stem cells（rMSCs） and find out the best therapeutic time.Methods： Primary rat bone marrow mesenchymalstem cells were obtained from Wistar rats and screened by the adhesive method.They were exposed to sinusoidal electromagnetic fieldswith 50 Hz frequency,1.8 mT intensity and 0.5 h,1.0 h,1.5 h,2.0 h and 2.5 h respectively,per day.The cultures without exposed as controlgroup.The osteogenic differentiation markers including ALP activity,osteocalcin secretion,mineralized bone modulus and collagen Iexpressions were compared among the exposed groups and the control.The total cellular RNA was extracted after 12h.The gene expres-sion of Osterix was examined by quantitative reverse transcription-polymerase chain reaction.Results： 1.0h treatment time stronglyenhances the osteogenic differentiation of rMSCs,indicated by significantly improved ALP activity,osteocalcin secretion,calcium depo-sition,collagen I expression and the number of mineralized bone nodules compared to the control and other groups.Osterix was also sig-nificantly improved（P0.05）.Conclusion： Low frequency sinusoidal electromagnetic fields at 50 Hz and 1.8mT enhance the osteogenicdifferentiation of rMSCs in different treatment time.Among them,1.0 h has the strongest activity,indicating that it may be the optimaltime for the clinical application.