An alkaloid from Menispermum dauricum, dauricine mediates Ca2+ influx and inhibits NF-κB pathway to protect chondrocytes from IL-1β-induced inflammation and catabolism

Dauricine (DA) is a natural plant-derived alkaloid extracted from Menispermum dauricum. Menispermum dauricum has been used in traditional Chinese medicine as a classic remedy for rheumatoid arthropathy and is believed to be effective in alleviating swelling and pain in the limbs. Osteoarthritis (OA) is a classic degenerative disease involving chondrocyte death, and there is still a lack of effective therapeutic agents that can reverse the progression of the disease. Here we explored the therapeutic effects of DA against OA and further explored the mechanism. The effect of DA on cell viability was assessed by CCK-8. IL-1β-treated mouse chondrocytes were used as an in vitro model of OA, and apoptosis was detected by flow cytometry. QRT-PCR, western blotting, cell staining, and immunofluorescence were used to detect relevant inflammatory factors and cartilage-specific expression. RNA sequencing was used to identify pertinent signaling pathways. The therapeutic effect of DA was verified by micro-CT, histological analysis and immunohistochemical analysis in a mouse OA model. DA demonstrated a high safety profile on chondrocytes, significantly reversing the inflammatory response induced by IL-1β, and promoting factors associated with cartilage regeneration. Moreover, DA exhibited a significant protective effect on the knee joints of mice undergoing ACLT-DMM, effectively preventing cartilage degeneration and subchondral bone tissue destruction. These positive therapeutic effects were achieved through the modulation of the NF-κB pathway and the Ca2+ signaling pathway by DA. Being derived from a traditional herb, DA exhibits remarkable therapeutic potential and safety in OA treatment, presenting a promising option for patients dealing with osteoarthritis.