The current study evaluated the hypothesis that the administration of spheroidal adipose‐derived stromal/stem cells (ASCs) promotes cell survival and arrests the progression of surgically induced osteoarthritis (OA) in a rat model. We also tested the optimal conditions for spheroid production from ASCs using microwell methods. The formation of ASC spheroids was optimized at a well diameter of 600 μm under cell concentrations of 10⁶cell/ml. When ASC spheroids cultured in 3D were compared with ASCs cultured in 2D monolayer, the cell survival and chondrogenic potential were enhanced while the apoptosis was reduced in ASC spheroids compared with ASCs in 2D monolayer culture. In vivo tracking of fluorescently labeled ASCs in the knee joints of rats with surgically induced OA showed longer fluorescent activity at a higher intensity in ASC spheroids than in ASC single‐cell suspension. When OA‐induced rats treated with ASC injection were sacrificed after 8 weeks, the OARSI score was enhanced in both ASC single‐cell suspension and ASC spheroids compared with negative control, spheroid treatment resulting in a better score than single‐cell treatment. However, injected cells were not detectable from the joints. These finding altogether suggests that ASC spheroids have better in vitro and in vivo survival and chondrogenic potential and exert greater regenerative effects for articular cartilage and arrest the progression of surgically induced OA better than ASCs in single‐cell suspension by the paracrine mode of action. The study findings support the notion of developing cell therapeutics to treat OA based on ASC spheroid forms.

中文翻译：

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脂肪来源的基质/干细胞球体与单细胞悬液在细胞存活和骨关节炎进展停滞中的表征

目前的研究评估了以下假设，即在大鼠模型中使用球形脂肪来源的基质/干细胞 (ASC) 可促进细胞存活并阻止手术诱发的骨关节炎 (OA) 的进展。我们还使用微孔方法测试了从 ASC 生产球体的最佳条件。在细胞浓度为 10 ^{6 的情况}下，在 600 μm 的孔直径下优化了 ASC 球体的形成细胞/毫升。当将 3D 培养的 ASC 球体与 2D 单层培养的 ASC 进行比较时，与 2D 单层培养中的 ASC 相比，ASC 球体的细胞存活率和软骨形成潜力得到增强，而细胞凋亡减少。对手术诱导的 OA 大鼠膝关节中荧光标记的 ASC 的体内追踪显示，与 ASC 单细胞悬液相比，ASC 球体中的荧光活性更高，强度更高。当 8 周后处死用 ASC 注射治疗的 OA 诱导的大鼠时，与阴性对照相比，ASC 单细胞悬液和 ASC 球体的 OARSI 评分均提高，球体治疗的评分优于单细胞治疗。然而，从关节中检测不到注射的细胞。这些发现共同表明，ASC 球体在体外和体内具有更好的存活率和软骨形成潜力，并对关节软骨发挥更大的再生作用，并通过旁分泌作用模式比单细胞悬液中的 ASCs 更好地阻止手术诱导的 OA 的进展。研究结果支持基于 ASC 球体形式开发细胞疗法来治疗 OA 的概念。