Traumatic knee injuries in humans trigger an immediate increase in synovial fluid levels of inflammatory cytokines that accompany impact damage to joint tissues. We developed a human in vitro cartilage-bone-synovium (CBS) coculture model to study the role of mechanical injury and inflammation in the initiation of post-traumatic osteoarthritis (PTOA)-like disease. Osteochondral plugs (cartilage-bone, CB) along with joint capsule synovium explants (S) were harvested from 25 cadaveric distal femurs from 16 human donors (Collin’s grade 0–2, 23–83years). Two-week monocultures (cartilage (C), bone (B), synovium (S)) and cocultures (CB, CBS) were established. A PTOA-like disease group was initiated via coculture of synovium explants with mechanically impacted osteochondral plugs (CBS+INJ, peak stress 5MPa) with non-impacted CB as controls. Disease-like progression was assessed through analyses of changes in cell viability, inflammatory cytokines released to media (10-plex ELISA), tissue matrix degradation, and metabolomics profile. Immediate increases in concentrations of a panel of inflammatory cytokines occurred in CBS+INJ and CBS cocultures and cultures with S alone (IL-1, IL-6, IL-8, and TNF-α among others). CBS+INJ and CBS also showed increased chondrocyte death compared to uninjured CB. The release of sulfated glycosaminoglycans (sGAG) and associated ARGS-aggrecan neoepitope fragments to the medium was significantly increased in CBS and CBS+INJ groups. Distinct metabolomics profiles were observed for C, B, and S monocultures, and metabolites related to inflammatory response in CBS versus CB (e.g., kynurenine, 1-methylnicotinamide, and hypoxanthine) were identified. CBS and CBS+INJ models showed distinct cellular, inflammatory, and matrix-related alterations relevant to PTOA-like initiation/progression. The use of human knee tissues from donors that had no prior history of OA disease suggests the relevance of this model in highlighting the role of injury and inflammation in earliest stages of PTOA progression.

中文翻译：

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炎症细胞因子和机械损伤在人体软骨-骨-滑膜微生理系统中诱导创伤后骨关节炎样变化


人类膝关节外伤会导致滑液中炎症细胞因子水平立即升高，从而导致关节组织受到冲击损伤。我们开发了一种人体体外软骨-骨-滑膜（CBS）共培养模型，以研究机械损伤和炎症在创伤后骨关节炎（PTOA）样疾病发生中的作用。从 16 名人类捐献者（Collin 0-2 级，23-83 岁）的 25 具尸体远端股骨中采集骨软骨栓（软骨骨，CB）和关节囊滑膜外植体（S）。建立了为期两周的单一培养物（软骨（C）、骨（B）、滑膜（S））和共培养物（CB、CBS）。通过将滑膜外植体与机械冲击骨软骨塞（CBS+INJ，峰值应力 5MPa）共培养，并以未冲击的 CB 作为对照，启动类 PTOA 疾病组。通过分析细胞活力、释放到介质中的炎症细胞因子（10 重 ELISA）、组织基质降解和代谢组学概况的变化来评估疾病样进展。在 CBS+INJ 和 CBS 共培养物以及单独 S 培养物中，一组炎症细胞因子的浓度立即增加（IL-1、IL-6、IL-8 和 TNF-α 等）。与未受伤的 CB 相比，CBS+INJ 和 CBS 还显示软骨细胞死亡增加。在 CBS 和 CBS+INJ 组中，硫酸化糖胺聚糖 (sGAG) 和相关 ARGS-聚集蛋白聚糖新表位片段向培养基的释放显着增加。在 C、B 和 S 单一培养物中观察到了不同的代谢组学特征，并且鉴定了 CBS 与 CB 中与炎症反应相关的代谢物（例如犬尿氨酸、1-甲基烟酰胺和次黄嘌呤）。 CBS 和 CBS+INJ 模型显示出与 PTOA 样启动/进展相关的明显细胞、炎症和基质相关改变。使用来自先前没有 OA 疾病史的捐赠者的人类膝关节组织表明该模型在强调损伤和炎症在 PTOA 进展早期阶段的作用方面具有相关性。