Senkyunolide I prevent chondrocytes from oxidative stress through Nrf2/HO-1 signaling pathway

Osteoarthritis (OA) is a degenerative musculoskeletal disease, featured by the destruction of articular cartilage. Oxidative stress, one of the drivers of the extracellular matrix degradation in cartilage, plays a vital role in OA pathogenesis. Senkyunolide I (SEI) is a natural compound with a prominent anti-oxidative stress property against multiple diseases. However, the protective effect of SEI on OA has not been explored. Here, we aimed to elucidate the effect of SEI on OA in vitro. Our results showed that SEI suppressed the expression of senescence-related markers such as P16 and P21 in IL-1β-induced chondrocytes. Besides, SEI alleviated IL-1β-induced the degradation of extracellular matrix (ECM) by suppressing the matrix proteinase like MMP13 and ATAMDS5 while promoting matrix synthesis regulated biomarkers like COL2A1 and ACAN in chondrocytes. Mechanically, the mitochondrial dysfunction and overproduction of intracellular reactive oxygen species (ROS) in chondrocytes induced by IL-1β were reversed by SEI. Additionally, the ROS inhibitor N-acetylcysteine (NAC) synergistically enhanced the biological effect of SEI in IL-1β-induced chondrocytes. Moreover, it was also found that the expression of Nrf2 and HO-1 was increased by the treatment of SEI in IL-1β-stimulated chondrocytes, while the Nrf2 inhibitor ML385 reversed the protective effect of SEI on OA chondrocytes. In conclusion, SEI could inhibit senescence, the degradation of ECM, and the production of ROS through activating Nrf2/ HO-1 signaling pathway, which provide a novel candidate for OA treatment.