Diallyl Disulfide Mitigates LPS-Induced Inhibition of Osteogenic Differentiation and Alleviates Inflammatory Bone Loss via PI3K/AKT Signaling Pathway

Background: Systemic inflammation impairs bone health by inhibiting the osteogenic differentiation of bone marrow stromal cells (BMSCs), thereby contributing to bone loss. Diallyl disulfide (DADS), a natural compound with anti-inflammatory properties, was investigated for its ability to mitigate inflammatory bone loss (IBL), reverse LPS-induced suppression of osteogenic differentiation, and elucidate the underlying mechanisms. Methods: An LPS-induced mouse model of IBL was used to evaluate the effects of DADS by micro-CT, histological and immunohistochemical staining, and serum ELISA. An in vitro model was established by exposing BMSCs to LPS. The optimal concentration of DADS was determined using a Cell Counting Kit-8 (CCK-8) assay. Osteogenic differentiation was evaluated by alkaline phosphatase (ALP) staining, Alizarin Red S (ARS) staining, immunofluorescence, and Western blot. Network pharmacology and transcriptome sequencing were employed to identify potential therapeutic mechanisms, and the PI3K/AKT pathway was verified using the inhibitor LY294002. Results: Micro-CT and histological analyses confirmed that DADS attenuated bone loss in the IBL mouse model. Toluidine blue staining and immunohistochemical analysis demonstrated that DADS promoted osteogenic differentiation. Immunohistochemical detection and serum ELISA of inflammatory cytokines revealed that DADS significantly reduced inflammatory levels in IBL mice. In vitro, the LPS-induced inhibition of osteogenic differentiation in BMSCs was reversed by DADS. Following DADS treatment, elevated ALP activity, matrix mineralization, and osteogenic marker expression, and reducing inflammatory mediators were observed. Network pharmacology and transcriptome sequencing revealed that DADS may exert its effects through the PI3K/AKT signaling pathway. Subsequent experiments conclusively established that DADS activated the PI3K/AKT signaling pathway. The osteogenic differentiation induced by DADS was inhibited by the PI3K inhibitor LY294002, indicating that the PI3K/AKT pathway is crucial in the osteogenic differentiation promoted by DADS. Conclusion: DADS counteracts LPS-induced bone loss by promoting osteogenic differentiation via PI3K/AKT activation, highlighting its therapeutic potential for inflammatory bone diseases.