Magnoflorine alleviates experimental osteoarthritis and is associated with altered M1- and M2-associated macrophage markers and subchondral bone remodeling

Abstract Osteoarthritis (OA) is a common degenerative joint disease characterized by cartilage degradation, abnormal subchondral bone remodeling, and macrophage-associated inflammation. Despite its high prevalence, effective disease‑modifying treatments remain lacking due to limited understanding of OA’s complex pathogenesis. Magnoflorine, an active compound from the traditional Chinese medicine formula San‑miao‑San, has reported anti-inflammatory and antioxidant activities, but its effects and the signaling changes associated with these effects in OA remain unclear. This study aimed to characterize the effects of magnoflorine in experimental OA and the signaling changes associated with these effects. In this study, an osteoarthritis model was induced in rats using medial meniscus destabilization (DMM), and magnoflorine was administered via intra-articular injection. The effects were assessed using micro-CT, histopathological staining, IF, and other techniques. Magnoflorine treatment was associated with improved joint degeneration scores, greater subchondral bone stability, better bone microarchitecture, improved cartilage morphology and matrix synthesis, and changes in osteogenesis-related markers. It was also associated with reduced M1-associated markers, increased M2-associated markers, and increased serum antioxidant enzyme activity. In vitro, magnoflorine showed no cytotoxicity at 25–100 µg/mL and was associated with restored cell viability, increased MC3T3-E1 cell migration, and reduced oxidative stress. It was also associated with reversal of osteoclast-conditioned medium-induced suppression of osteogenic differentiation. The observed effects of magnoflorine were associated with changes in a ROS-associated regulatory network. The observed effects were associated with changes in ROS-related signaling, including reduced ROS levels, attenuated MAPK and NF-κB activation, enhanced Nrf2-associated antioxidant responses, and changes in BMP2/SMAD-associated signaling. These associations may contribute to the anti-inflammatory and pro-osteogenic effects of magnoflorine; however, a sequential causal cascade was not established. These findings suggest that magnoflorine warrants further investigation as a potential disease-modifying candidate for OA and provide experimental context for understanding the modern scientific basis of traditional Chinese medicine in OA treatment.