Secondary osteoarthritis (OA) is a slow progressive, common disorder of synovial joints in dogs. It is characterized by a loss of balance between the synthesis and degeneration of articular cartilage components. Its diagnosis is currently based on the presence of clear radiographic changes, which only occur in the later stages of the disease. Hence, early diagnosis of OA remains a major problem. Therefore, interest in synovial fluid (SF) biomarkers has emerged. Besides pro-inflammatory and degenerative markers, i.e. tumor necrosis factor alpha (TNF-alpha), interleukin-1beta (IL-1beta), tenascin-c (TN-C) and matrix metalloproteinase-2 (MMP-2), metabolic parameters, i.e. pH, glucose and lactate, can potentially be used to detect OA.

The current study demonstrated statistically significant differences in the SF levels of pH, glucose and lactate between OA-affected and normal joints. In addition, the in-house validated immuno-assays for TNF-alpha, IL-1beta, TN-C and MMP-2 allowed to demonstrate also statistically significant differences in the SF concentrations for all these biomarkers - except TNF-alpha - between OA-affected and normal joints. However, no correlation was found between any of these biomarkers and the currently used radiographic scoring system for OA in dogs.

Future research is warranted to explore the potential of these biomarkers in the early detection of OA and in the severity characterization of this disease.

继发性骨关节炎 (OA) 是犬滑膜关节的一种缓慢进展的常见疾病。它的特点是关节软骨成分的合成和退化之间失去平衡。其诊断目前基于明确的影像学变化，这种变化仅发生在疾病的后期阶段。因此，OA的早期诊断仍然是一个主要问题。因此，出现了对滑液 (SF) 生物标志物的兴趣。除了促炎和退行性标志物，即肿瘤坏死因子 α (TNF-α)、白细胞介素-1β (IL-1β)、生腱蛋白-c (TN-C) 和基质金属蛋白酶-2 (MMP-2)，代谢参数，即 pH、葡萄糖和乳酸，可潜在地用于检测 OA。

目前的研究表明，受 OA 影响的关节和正常关节之间的 SF 水平的 pH、葡萄糖和乳酸水平存在统计学显着差异。此外，针对 TNF-α、IL-1β、TN-C 和 MMP-2 的内部验证免疫测定也允许证明所有这些生物标志物的 SF 浓度（TNF-α 除外）在 OA 之间存在统计学显着差异- 受影响的和正常的关节。然而，在这些生物标志物与目前使用的犬 OA 放射影像评分系统之间没有发现相关性。

未来的研究有必要探索这些生物标志物在 OA 早期检测和该疾病严重程度表征中的潜力。