Osteoarthritis (OA) is a chronic degenerative bone and joint disease that often occurs in aging animals. Currently, there are still no biomarkers that can effectively diagnose OA in the early stage. To identify possible biomarkers, here we examined changes in the expression of C‐telopeptide fragments of type II collagen (CTX‐II) and collagenase generated carboxy‐terminal neoepitope of type II collagen (C2C) in serum at different time points in an anterior cruciate ligament transection (ACLT)‐induced rat OA model. The serum levels of CTX‐II and C2C, and the OARSI score in the ACLT group were increased from week two until the end of the experiment. The AUC of the combined biomarkers was higher than that of CTX‐II or C2C alone. Moreover, serum levels of CTX‐II and C2C were positively correlated with the OARSI score. The results suggest that the combined detection of serum CTX‐II and C2C concentrations may have potential for assessing and diagnosing OA at early stages.

BackgroundLameness caused by osteoarthritis (OA) is one of the main causes of disability in elderly dogs. Non-steroidal anti-inflammatory drugs (NSAIDs) are important tools in the treatment of canine OA. In recent years, due to the many side effects of NSAIDs, patients cannot tolerate or do not want to take the risk of NSAIDs. People are becoming more and more interested in new treatments for canine OA, and so-called nutritional supplements have emerged. Puerarin has a wide range of pharmacological activities and is often used as a clinical prescription drug and dietary supplement in China. However, the effect of puerarin on canine OA has not been evaluated. Therefore, the purpose of this study is to evaluate the anti-inflammatory and anti-cartilage degradation effects of puerarin in a canine OA model induced by anterior cruciate ligament transection (ACLT), and to detect the serum inflammatory factor interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor α (TNF-α) levels and cartilage degradation biomarker C-terminal telopeptides of collagen type II (CTX-II), cartilage oligomeric matrix protein (COMP) and chondroitin sulfate 846 epitope (CS 846) levels in serum and synovial fluid at different periods of puerarin administration. ResultsEight weeks after the administration, the veterinarian performed clinical and imaging evaluations to comprehensively evaluate the protective effect of puerarin on canine OA. Daily oral administration of 20 mg/kg puerarin can significantly inhibit the expression of IL-1β, IL-6 and TNF-α in serum within 8 weeks (P < 0.05), and its anti-inflammatory effect is similar to oral celecoxib (negative control group). Puerarin has a certain protective effect on articular cartilage and can reduce the level of biomarkers CTX-II, COMP and CS 846 in serum and synovial fluid in the early stage of OA (P < 0.05). In addition, the clinical scores and radiographs scores were significantly reduced after 8 weeks of puerarin treatment (P < 0.05). ConclusionsCanine OA cartilage may be mediated through anti-inflammatory, anti-metabolism and anabolic effects, and strongly down-regulate the inflammatory factors IL-1β, IL-6 and TNF-α and cartilage degradation biomarkers CTX-II, COMP and CS 846 are related, providing a good alternative therapy for OA.