It was found that preosteoblast MC3T3-E1 cells were less responsive in calcium signaling than mature osteocyte MLO-Y4 cells when a steady fluid flow was exerted on a micropatterned cell network. However, the effect of fluid flow on the calcium response in preosteocyte MLO-A5 was seldom investigated. In the present study, MLO-A5 as well as MC3T3-E1 and MLO-Y4 cells were cultured on a regular substrate with high or low density under unidirectional or oscillatory fluid flow. The results showed that calcium oscillation in the cells during late osteogenesis was significantly stronger than during early osteogenesis regardless of the fluid flow type or the presence of a physical cell-cell connection. Calcium oscillation produced by the oscillatory flow in the three types of cells was stronger than that produced by the unidirectional flow, but MC3T3-E1 and MLO-A5 cells exhibited limited potential for calcium oscillation compared with MLO-Y4 cells. After suramin was used to block the binding of extracellular adenosine triphosphate (ATP) to the membrane P2 receptor, the calcium oscillation in the three types of bone cells with or without physical connections was significantly suppressed as a single responsive peak under unidirectional flow. For the ATP-blocking group of low-density cells under oscillatory flow, the number of oscillation peaks in three types of cells was still more than two. It indicates that besides the ATP pathway, other mechanosensitive calcium pathways may exist under oscillatory flow. The present study provided further evidence for the osteogenic stage-dependent calcium response of bone cells under unidirectional or oscillatory fluid flow.

中文翻译：

---

在单向或振荡流动下，不同成骨阶段骨细胞中的钙反应。

已发现，当在微模式细胞网络上施加稳定的流体流动时，成骨细胞MC3T3-E1细胞在钙信号传导方面的响应要比成熟的骨细胞MLO-Y4细胞低。但是，很少研究流体流动对前骨细胞MLO-A5中钙反应的影响。在本研究中，MLO-A5以及MC3T3-E1和MLO-Y4细胞在单向或振荡流体流动下，以高密度或低密度的规则底物培养。结果表明，无论流体流动类型或存在物理的细胞-细胞连接，成骨晚期晚期细胞中的钙振荡明显强于早期成骨阶段。在三种类型的电池中，振荡流产生的钙振荡要比单向流产生的钙振荡强，但是与MLO-Y4细胞相比，MC3T3-E1和MLO-A5细胞的钙振荡潜力有限。在将苏拉明用于阻断细胞外三磷酸腺苷（ATP）与膜P2受体的结合后，在单向流动下，作为单个响应峰，三种具有或不具有物理连接的骨细胞中的钙振荡都被显着抑制。对于低密度细胞在振荡流下的ATP阻滞组，三种细胞的振荡峰数仍大于两个。这表明，除了ATP途径外，在振荡流动下还可能存在其他机械敏感性钙途径。本研究为骨细胞在单向或振荡流体流动下成骨阶段依赖性钙反应提供了进一步的证据。