Astragalin mitigates inflammatory osteolysis by negatively modulating osteoclastogenesis via ROS and MAPK signaling pathway

Inflammatory bone destruction has gradually attracted attention worldwide and has been observed in several kinds of pathological bone diseases, such as osteoarthritis, osteomyelitis, rheumatic arthritis, and other infectious clinical trials in the skeletal system. In this regard, excessive osteoclasts and bone resorption activity participate in osteolytic processes. Thus, negatively modulating osteoclast differentiation and bone erosion has been considered an effective therapeutic strategy to limit the poor progression of inflammatory osteolysis. Astragalin (AST) is a bioactive component of traditional Chinese drugs, such as Rosa agrestis, which presents anti-inflammatory and antioxidant effects. However, it is unclear how AST may play an essential role in regulating the dynamic balance of the bone matrix by affecting osteoclastogenesis. This study found that AST could inhibit osteoclastic formation and bone resorption activity in a dose-dependent manner without cytotoxicity. Administration of AST also inhibited the expression of cathepsin K, c-Fos, NFATc1, and TRAP at different stages of mRNA and protein levels during osteoclastogenesis. Reactive oxygen species (ROS) signalling could also be modulated by treatment with AST during RANKL-induced osteoclast differentiation through the Nrf2-HO1 signalling pathway. Additionally, AST could negatively regulate mitogen-activated protein kinase (MAPK) signalling in this process. In vivo, AST significantly reduced lipopolysaccharide (LPS)-induced bone loss in an osteolytic mouse model. AST might be a promising therapeutic candidate for treating osteolytic bone diseases in the future.