Srivastava Vanshika, Harsulkar Abhay, Aphale Shama, Märtson Aare, Kõks Sulev, Kulkarni Priya, Deshpande Shantanu
Department of Pharmaceutical Biotechnology, Poona College of Pharmacy, Bharati Vidyapeeth Deemed to be University, Erandwane, Pune 411038, India.
Department of Traumatology and Orthopaedics, Institute of Clinical Medicine, University of Tartu, L Puusepa 8, 51014 Tartu, Estonia.
Biomedicines. 2025 Apr 4;13(4):878. doi: 10.3390/biomedicines13040878.
Besides conventional norms that recognize synovial fluid (SF) as a joint lubricant, nutritional channel, and a diagnostic tool in knee osteoarthritis (kOA), based on the authors previous studies, this study aims to define functional role of SF in kOA. U937, a monocytic, human myeloid cell line, was induced with progressive grades of kOA SF, and the induction response was assessed on various pro-inflammatory parameters. This 'SF challenge test model' was further extended to determine the impact of SF on U937 differentiation using macrophage-specific markers and associated transcription factor genes. Mitochondrial membrane potential changes in SF-treated cells were evaluated with fluorescent JC-1 probe. a significant increase in nitric oxide, matrix metalloproteinase () 1, 13, and vascular endothelial growth factor ()-1 was noted in the induced cells. A marked increase was seen in , , and the transcription factors -activator protein , interferon regulatory factor , and signal transducer and activator of transcription in the SF-treated cells indicating active monocytes to macrophage differentiation. Reduced mitochondrial membrane potential was reflected by a reduced red-to-green ratio in JC-1 staining. these results underline the active role of OA SF in stimulating and maintaining inflammation in joint cells, fostering monocyte differentiation into pro-inflammatory macrophages. The decline in the membrane potential suggestive of additional inflammatory pathway in OA via the release of pro-apoptotic factors and damaged associated molecular patterns (DAMPs) within the cells. Overall, biochemical modulation of SF warrants a potential approach to intervene inflammatory cascade in OA and mitigate its progression.
除了将滑液（SF）视为关节润滑剂、营养通道以及膝关节骨关节炎（kOA）诊断工具的传统标准外，基于作者之前的研究，本研究旨在明确SF在kOA中的功能作用。使用不同程度的kOA滑液诱导人单核细胞系U937，并评估其对各种促炎参数的诱导反应。这个“SF挑战测试模型 ”被进一步扩展，以使用巨噬细胞特异性标志物和相关转录因子基因来确定SF对U937分化的影响。用荧光JC-1探针评估经SF处理的细胞中的线粒体膜电位变化。在诱导细胞中观察到一氧化氮、基质金属蛋白酶（MMP）-1、13和血管内皮生长因子（VEGF）-1显著增加。在经SF处理的细胞中，MMP-1、MMP-13以及转录因子激活蛋白-1（AP-1）、干扰素调节因子-1（IRF-1）和信号转导子与转录激活子-1（STAT-1）显著增加，表明单核细胞向促炎巨噬细胞的活跃分化。JC-1染色中红绿比降低反映了线粒体膜电位降低。这些结果强调了骨关节炎滑液在刺激和维持关节细胞炎症、促进单核细胞分化为促炎巨噬细胞方面的积极作用。膜电位下降表明骨关节炎中通过细胞内促凋亡因子和损伤相关分子模式（DAMPs）的释放存在额外的炎症途径。总体而言，滑液的生化调节为干预骨关节炎炎症级联反应并减轻其进展提供了一种潜在方法。
