Dihydroartemisinin ameliorates hemarthrosis-induced cartilage degeneration by suppressing chondrocyte senescence via activation of Keap1-Nrf2 signaling pathway.

BACKGROUND: Joint bleeding (hemarthrosis) is a major manifestation of joint trauma, especially repeated and spontaneous in hemophilia patients. Hemarthrosis has been identified to induce the excessive reactive oxygen species (ROS) accumulation and permanent damage in articular cartilage. Dihydroartemisinin (DHA), a well-known clinical anti-malaria drug with few sides effects therapy, has been reported to possess anti-oxidative activity. This study was aimed at exploring the effect of DHA on blood-induced cartilage erosion and its underlying mechanisms. METHODS: Two distinct hemarthrosis models were constructed respectively by fresh blood joint injection in WT and joint needle puncture in F8 (-/-) mice, and then treated with DHA (10 or 20 mg/kg/day) for 4 weeks. In vitro chondrocytes treated with frozen-thaw blood and DHA (1, 5 or 10 μM) for 24 h. Histopathological, immunofluorescence and western blotting were investigated to demonstrate the effects of DHA on blood-induced chondrocyte senescence, ROS accumulation and extracellular matrix (ECM) degradation. Additionally, Nrf2 inhibitor (MLB385, 30 mg/kg for once a four days) and Nrf2-siRNA were used to investigate the relationship between DHA and Nrf2/Keap1 signaling in vitro and in vivo, respectively. RESULTS: DHA remarkably ameliorated the cartilage degeneration in both two hemarthrosis models. Similarly, in vitro experiments confirmed that DHA promoted the synthesis of ECM in blood-stimulated chondrocytes with a dose-dependent manner. DHA also effectively suppressed blood-induced chondrocyte senescence and ROS accumulation. Mechanistically, DHA activated the Nrf2 signaling by accelerating Keap1 ubiquitination and degradation. Furthermore, Nrf2 siRNA and antagonist abolished the anti-senescence and anti-oxidative functions of DHA, resulting the severe cartilage degeneration in bleeding joint of F8 (-/-) mice. CONCLUSION: Our findings indicate that DHA effectively reduces chondrocyte senescence and mitigates cartilage destruction following hemarthrosis via activation of Nrf2/Keap1 signaling pathway. THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE: On the one hand, this study highlights the important role of chondrocyte senescence in hemarthrosis-induced cartilage degradation, implying that inhibiting chondrocyte senescence may be a viable therapeutic strategy for blood-induced arthropathy. On the other hand, our findings demonstrate the remarkable chondroprotective effect of DHA in bleeding joint by modulating the Nrf2/Keap1 anti-oxidative signaling pathway, suggesting DHA may serve as a potential candidate drug for the therapy of blood-induced arthropathy.