Department of Orthopedic Surgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
Phys Ther. 2012 Sep;92(9):1208-19. doi: 10.2522/ptj.20110224. Epub 2012 May 10.
Electromagnetic fields (EMFs) used in stem-cell tissue engineering can help elucidate their biological principles.
The aim of this study was to investigate the effects of low-intensity EMFs on cell proliferation, differentiation, and cycle in mouse bone marrow stromal cells (BMSCs) and the in vivo effects of EMFs on BMSC.
Harvested BMSCs were cultured for 3 generations and divided into 4 groups. The methylthiotetrazole (MTT) assay was used to evaluate cell proliferation, and alkaline phosphatase activity was measured via a colorimetric assay on the 3rd, 7th, and 10th days. Changes in cell cycle also were analyzed on the 7th day, and bone nodule formation was analyzed on the 12th day. Additionally, the expression of the collagen I gene was examined by reverse transcription-polymerase chain reaction (RT-PCR) on the 10th day. The BMSCs of the irradiated group and the control group were transplanted into cortical bone of different mice femurs separately, with poly(lactic-co-glycolic acid) (PLGA) serving as a scaffold. After 4 and 8 weeks, bone the bone specimens of mice were sliced and stained by hematoxylin and eosin separately.
The results showed that EMFs (0.5 mT, 50 Hz) accelerated cellular proliferation, enhanced cellular differentiation, and increased the percentage of cells in the G(2)/M+S (postsynthetic gap 2 period/mitotic phase + S phase) of the stimulation. The EMF-exposed groups had significantly higher collagen I messenger RNA levels than the control group. The EMF + osteogenic medium-treated group readily formed bone nodules. Hematoxylin and eosin staining showed a clear flaking of bone tissue in the irradiated group.
Irradiation of BMSCs with low-intensity EMFs (0.5 mT, 50 Hz) increased cell proliferation and induced cell differentiation. The results of this study did not establish a stricter animal model for studying osteogenesis, and only short-term results were investigated. Further study of the mechanism of EMF is needed.
在干细胞组织工程中使用电磁场（EMF）有助于阐明其生物学原理。
本研究旨在探讨低强度 EMF 对小鼠骨髓基质细胞（BMSC）增殖、分化和细胞周期的影响，以及 EMF 对 BMSC 的体内影响。
采集 BMSC 进行 3 代培养，分为 4 组。采用甲基噻唑四唑（MTT）法评估细胞增殖，第 3、7、10 天通过比色法测定碱性磷酸酶活性。第 7 天分析细胞周期变化，第 12 天分析骨结节形成。此外，第 10 天通过逆转录-聚合酶链反应（RT-PCR）检测胶原 I 基因的表达。将照射组和对照组的 BMSC 分别移植到不同小鼠股骨皮质骨中，以聚乳酸-共-羟基乙酸（PLGA）为支架。4 周和 8 周后，分别对小鼠骨标本进行切片和苏木精-伊红染色。
结果表明，EMF（0.5 mT，50 Hz）加速细胞增殖，增强细胞分化，增加刺激后细胞处于 G2/M+S（合成后间隙 2 期/有丝分裂期+S 期）的比例。暴露于 EMF 的组的胶原 I 信使 RNA 水平明显高于对照组。经 EMF+成骨培养基处理的组易于形成骨结节。苏木精-伊红染色显示照射组骨组织有明显的片状脱落。
低强度 EMF（0.5 mT，50 Hz）照射 BMSC 可增加细胞增殖并诱导细胞分化。本研究结果未建立更严格的成骨动物模型，仅研究了短期结果。需要进一步研究 EMF 的作用机制。
