Isoginkgetin Inhibits RANKL-induced Osteoclastogenesis and Alleviates Bone Loss

Osteoporosis is characterized by excessive osteoclast activity leading to bone loss, decreased bone mineral density, and increased susceptibility to fractures. Through in vivo/vitro experiments, along with network pharmacology analysis, we aimed to explore the underlying mechanisms of Isoginkgetin (IGG) in inhibiting osteoclastogenesis, providing valuable insights for further research in the future. Firstly, we ascertained the safe concentration of IGG stimulation on BMMs, followed by a systematic exploration of the concentration gradient at which IGG inhibited osteoclastogenesis using TRAP analysis. An osteoporosis model was established to further validate the in vitro experimental findings by combining Micro-CT and immunohistochemical analysis. The results show that IGG did not exhibit cytotoxicity or proliferative effects on BMMs at concentrations equal to or less than 10 μM. Additionally, IGG inhibited the activity of osteoclastogenesis and bone resorption function at lower concentrations. RT-PCR and Western Blot results demonstrated that IGG could downregulate genes and proteins associated with osteoclastogenesis. The Western Blot results also showed that IGG inhibited the phosphorylation expression of P38, ERK, and P65 in the MAPK and NF-κB pathways. At the same time, it rescued the degradation of IκB-α at 15 and 60 min. IGG can also impact the relative expression levels of oxidative proteins such as SOD-1, HO-1, and catalase, thereby influencing cellular equilibrium and stress levels, ultimately inhibiting the formation of mature OC. In vivo experiments demonstrated that IGG alleviated bone loss caused by osteoclasts and improved relevant parameters of trabecular bone. So, IGG effectively attenuated osteoclastogenesis, and improved bone density, thereby portraying its role in osteoporosis management.