不同频率脉冲电磁场诱导人骨髓间充质干细胞成骨分化的研究

目的探讨脉冲电磁场(PEMF)诱导人骨髓间充质干细胞(MSCs)成骨分化的适合频率。方法选用场强1．1mT，频率分别为5，25，50，75，100和150Hz的PEMF作用于MSCs，每日30min，连续作用2ld，光镜下观察细胞形态变化，电镜下观察细胞超微结构，酶化学法和放免技术检测细胞的碱性磷酸酶(ALP)含量和骨钙素(OC)表达情况。结果不同频率PEMF作用组均能诱导MSCs向成骨细胞分化；从5～50Hz频段，PEMF的成骨诱导作用随着频率的增加而增强；从50～150Hz频段，PEMF的成骨诱导作用随着频率的增加而减弱。结论频率是PEMF诱导MSCs成骨分化的重要影响因素之一，50Hz可能为诱导MSCs体外成骨分化的适合频率。

An experimental study on inducing human mesenchymal stem cells into osteoblasts by different frequencies of pulsed electromagnetic fields

Objective To study the suitable frequency of pulsed electromagnetic fields (PEMF) for inducing human mesenchymal stem cells(MSCs) differentiation. Methods The third generation of human mesenchymal stem cells were irradiated by different frequencies of PEMF of 5,25,50,75,100,150Hz, 1.1mT, for 30min/d for 21 days. Morphological changes of the MSCs were observed under phase contrast microscope. The activity of Alkaline phosphatase (ALP) and the expression of osteocalcin (OC) were measured by enzymology and radioimmunity methods to evaluate MSCs differentiation. Results Different frequencies of PEMF employed in this study showed different effects in inducing MSCs into osteoblasts. The differentiation of MSCs was increasing when the frequency of PEMF was increased gradually from 5Hz to 50Hz, and then decreasing when the frequency of PEMF was increased from 50Hz to 150Hz. Conclusion Frequency of PEMF was one of the most important factors in inducing MSCs differentiation. This study indicated that 50Hz was the suitable frequency of PEMF for inducing MSCs into osteoblast in vitro.