Low back pain (LBP) is a major physical and socioeconomic challenge worldwide. Nucleus pulposus (NP) is directly associated with LBP due to intervertebral disc (IVD) degeneration. IVD degeneration is mainly caused by structural and matrix-related changes within the IVD occurring during aging and degeneration. Mesenchymal stem cells (MSCs) can differentiate into multiple mesenchymal lineages under specific stimulatory conditions. This study is aimed at evaluating the effectiveness of the nucleus pulposus cell (NPC) conditioned medium for promoting the expression of MSCs and at confirming the expression of healthy NP phenotypic markers recently recommended by the Spine Research Interest Group. Expression was investigated using quantitative polymerase chain reaction (qPCR) and western blotting under normoxic and hypoxic conditions. qPCR and western blotting demonstrated significant upregulation of NP marker expression in MSCs cultured under hypoxic conditions and treated with the 50% or 100% NPC conditioned medium, compared with those cultured under normoxic conditions. Upregulation was highest in the presence of the 100% NPC conditioned medium compared with the control group (aggrecan, ; brachyury, ; collagen II, ; KRT8, ; KRT19, ; and Shh, ). The expression levels of genes in MSCs treated with the 50% NPC conditioned medium also showed upregulation compared with the control group (collagen II, ; KRT8, ; and KRT19, ). These findings suggested that the NPC conditioned medium stimulated MSC differentiation into an NP-like phenotype with distinct characteristics. The results could inform strategies for IVD regeneration.

中文翻译：

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缺氧条件下髓核细胞条件培养基促进间充质干细胞分化为髓核样细胞

下腰痛（LBP）是全球范围内的一项重大身体和社会经济挑战。由于椎间盘（IVD）变性，髓核（NP）与LBP直接相关。IVD变性主要是由IVD内部在老化和变性过程中发生的结构和基质相关变化引起的。在特定刺激条件下，间充质干细胞（MSC）可以分化为多个间充质谱系。这项研究旨在评估髓核细胞（NPC）条件培养基对促进MSCs表达的有效性，并确认Spine研究兴趣小组最近推荐的健康NP表型标记的表达。在常氧和低氧条件下，使用定量聚合酶链反应（qPCR）和Western印迹研究表达。与在常氧条件下培养的MSC相比，qPCR和western blotting显示在低氧条件下培养的MSC中，NP标记表达显着上调，并用50％或100％NPC条件培养基处理。与对照组相比，在100％NPC条件培养基的存在下，上调最高; brachyury，; 胶原蛋白II; KRT8，; KRT19，; 嘘）。与对照组相比，用50％NPC条件培养基处理的MSC中的基因表达水平也表达上调（胶原II，; KRT8，; 和KRT19，）。这些发现表明，NPC条件培养基刺激MSC分化为具有独特特征的NP样表型。结果可以为IVD再生策略提供参考。