Kim Yu-Mi, Lim Han-Moi, Lee Eun-Chul, Ki Ga-Eun, Seo Young-Kwon
Department of Medical Biotechnology (BK21 Plus Team), Dongguk University, Goyang-si, Korea.
J Orthop Res. 2021 Aug;39(8):1633-1646. doi: 10.1002/jor.24905. Epub 2021 Jan 13.
Electromagnetic fields (EMFs) are widely used in a number of cell therapies and bone disorder treatments, and nanomagnetic particles (NMPs) also promote cell activity. In this study, we investigated the synergistic effects of EMFs and NMPs on the osteogenesis of the human Saos-2 osteoblast cell line and in a rat calvarial defect model. The Saos-2 cells and critical-size calvarial defects of the rats were exposed to EMF (1 mT, 45 Hz, 8 h/day) with or without Fe O NMPs. Biocompatibility was evaluated with MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and LDH (lactate dehydrogenase) assays. This analysis showed that NMP and EMF did not induce cell toxicity. Quantitative reverse-transcription polymerase chain reaction indicated that the osteogenesis-related markers were highly expressed in the NMP-incorporated Saos-2 cells after exposure to EMF. Also, the expression of gene-encoding proteins involved in calcium channels was activated and the calcium concentration of the NMP-incorporated + EMF-exposed group was increased compared with the control group. In particular, in the NMP-incorporated + EMF-exposed group, all osteogenic proteins were more abundantly expressed than in the control group. This indicated that the NMP incorporation + EMF exposure induced a signaling pathway through activation of p-ERK and calcium channels. Also, in vivo evaluation revealed that rat calvarial defects treated with EMFs and NMPs had good regeneration results with new bone formation and increased mineral density after 6 weeks. Altogether, these results suggest that NMP treatment or EMF exposure of Saos-2 cells can increase osteogenic activity and NMP incorporation following EMF exposure which is synergistically efficient for osteogenesis.
电磁场（EMFs）广泛应用于多种细胞疗法和骨疾病治疗中，纳米磁性颗粒（NMPs）也能促进细胞活性。在本研究中，我们调查了电磁场和纳米磁性颗粒对人Saos-2成骨细胞系成骨作用以及大鼠颅骨缺损模型的协同效应。将大鼠的Saos-2细胞和临界尺寸颅骨缺损暴露于有或无Fe₃O₄纳米磁性颗粒的电磁场（1 mT，45 Hz，每天8小时）中。通过MTT（3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四氮唑溴盐）和LDH（乳酸脱氢酶）测定评估生物相容性。该分析表明纳米磁性颗粒和电磁场未诱导细胞毒性。定量逆转录聚合酶链反应表明，暴露于电磁场后，掺入纳米磁性颗粒的Saos-2细胞中与成骨相关的标志物高度表达。此外，与对照组相比，掺入纳米磁性颗粒 + 暴露于电磁场组中参与钙通道的基因编码蛋白的表达被激活，且钙浓度增加。特别是，在掺入纳米磁性颗粒 + 暴露于电磁场组中，所有成骨蛋白的表达均比对照组更丰富。这表明掺入纳米磁性颗粒 + 暴露于电磁场通过激活p-ERK和钙通道诱导了一条信号通路。此外，体内评估显示，用电磁场和纳米磁性颗粒治疗的大鼠颅骨缺损在6周后有良好的再生结果，有新骨形成且矿物质密度增加。总之，这些结果表明，对Saos-2细胞进行纳米磁性颗粒处理或电磁场暴露可增加成骨活性，且电磁场暴露后掺入纳米磁性颗粒对成骨具有协同增效作用。
