Department of Materials, The University of Manchester, Manchester, UK.
Instituto de Micro y Nanotecnología IMN-CNM, The Spanish National Research Council (CSIC), Madrid, Spain.
Biotechnol Bioeng. 2019 Dec;116(12):3421-3432. doi: 10.1002/bit.27142. Epub 2019 Sep 23.
The capability of electrical stimulation (ES) in promoting bone regeneration has already been addressed in clinical studies. However, its mechanism is still being investigated and discussed. This study aims to investigate the responses of macrophages (J774A.1) and preosteoblasts (MC3T3-E1) to ES and the faradic by-products from ES. It is found that pH of the culture media was not significantly changed, whereas the average hydrogen peroxide concentration was increased by 3.6 and 5.4 µM after 1 and 2 hr of ES, respectively. The upregulation of Bmp2 and Spp1 messenger RNAs was observed after 3 days of stimulation, which is consistent among two cell types. It is also found that Spp1 expression of macrophages was partially enhanced by faradic by-products. Osteogenic differentiation of preosteoblasts was not observed during the early stage of ES as the level of Runx2 expression remains unchanged. However, cell proliferation was impaired by the excessive current density from the electrodes, and also faradic by-products in the case of macrophages. This study shows that macrophages could respond to ES and potentially contribute to the bone formation alongside preosteoblasts. The upregulation of Bmp2 and Spp1 expressions induced by ES could be one of the mechanisms behind the electrically stimulated osteogenesis.
电刺激（ES）在促进骨再生方面的能力已经在临床研究中得到了证实。然而，其机制仍在研究和讨论中。本研究旨在探讨巨噬细胞（J774A.1）和前成骨细胞（MC3T3-E1）对 ES 和 ES 的电化学副产品的反应。结果发现，培养介质的 pH 值没有明显变化，而 ES 刺激 1 和 2 小时后，平均过氧化氢浓度分别增加了 3.6 和 5.4µM。刺激 3 天后，两种细胞类型均观察到 Bmp2 和 Spp1 信使 RNA 的上调。还发现，电化学副产品部分增强了巨噬细胞的 Spp1 表达。在 ES 的早期阶段，前成骨细胞没有观察到成骨分化，因为 Runx2 表达水平保持不变。然而，细胞增殖受到电极产生的过高电流密度以及巨噬细胞中电化学副产品的影响。本研究表明，巨噬细胞可以对 ES 做出反应，并与前成骨细胞一起潜在地促进骨形成。ES 诱导的 Bmp2 和 Spp1 表达上调可能是电刺激成骨作用的机制之一。
