骨细胞的细胞内感染代表了骨髓炎的临床重要方面。然而，人类骨细胞体外模型很少，并且未成熟的成骨细胞分化为骨细胞阶段通常需要至少 4 周的培养时间，使得这一过程的研究充满挑战且耗时。骨肉瘤细胞系Saos-2已被证明是人类成骨细胞向成熟骨细胞分化的有用模型。在标准含氧量 (21% O2) 气氛中的成骨条件下培养，可在预期的 28-35 天培养期内实现可重复的矿化和成熟骨细胞标记物的获得。为了加快实验测定，我们测试了将可用氧减少到模拟体内骨细胞经历的浓度是否会增加分化率。在 1% O2 下培养的细胞在 14 天时表现出最大的矿物质沉积。与常氧条件下相比，早期（COLA1、MEPE）和成熟（PHEX、DMP1、GJA1、SOST）骨细胞标记物在缺氧条件下更早上调。在 1% O2 下分化 14 天的细胞表现出与在常氧条件下生长第 28 天的细胞相似的内化金黄色葡萄球菌的能力。因此，低氧会加速 Saos-2 骨细胞分化，从而在 14 天内形成有用的人类骨细胞样细胞模型。© 2023 作者。生理报告由 Wiley periodicals LLC 代表生理学会和美国生理学会出版。

The intracellular infection of osteocytes represents a clinically important aspect of osteomyelitis. However, few human osteocyte in vitro models exist and the differentiation of immature osteoblasts to an osteocyte stage typically takes at least 4-weeks of culture, making the study of this process challenging and time consuming. The osteosarcoma cell line Saos-2 has proved to be a useful model of human osteoblast to mature osteocyte differentiation. Culture under osteogenic conditions in a standard normoxic (21% O2 ) atmosphere results in reproducible mineralization and acquisition of mature osteocyte markers over the expected 28-35 day culture period. In order to expedite experimental assays, we tested whether reducing available oxygen to mimic concentrations experienced by osteocytes in vivo would increase the rate of differentiation. Cells cultured under 1% O2 exhibited maximal mineral deposition by 14 days. Early (COLA1, MEPE) and mature (PHEX, DMP1, GJA1, SOST) osteocyte markers were upregulated earlier under hypoxia compared to normoxia. Cells differentiated under 1% O2 for 14 days displayed a similar ability to internalize Staphylococcus aureus as day 28 cells grown under normoxic conditions. Thus, low oxygen accelerates Saos-2 osteocyte differentiation, resulting in a useful human osteocyte-like cell model within 14 days.© 2023 The Authors. Physiological Reports published by Wiley Periodicals LLC on behalf of The Physiological Society and the American Physiological Society.