Ginsenoside Rh2 attenuates pyroptosis by inhibiting the PAFR/NF-κB signaling pathway in an osteoarthritis cell model.

Osteoarthritis (OA) is a prevalent joint disorder marked primarily by the progressive breakdown of articular cartilage. Pyroptosis, an inflammatory programmed cell death mechanism, exacerbates OA progression. Ginsenoside Rh2 (Rh2), a bioactive compound derived from traditional Chinese medicine, has shown potential therapeutic effects in OA. However, its underlying molecular mechanisms in OA treatment remain to be fully elucidated. To investigate the therapeutic potential of Rh2, an in vitro OA model was generated via LPS treatment of human chondrocytes (C-28/I2). The anti-inflammatory and anti-pyroptotic properties of Rh2 were subsequently assessed by quantifying the levels of key inflammatory cytokines using ELISA, immunofluorescence assessment of extracellular matrix components, Western blot analysis of pyroptosis-related proteins, and LDH release assays. The interaction between Rh2 and platelet-activating factor receptor (PAFR) was verified using molecular docking and cellular thermal shift assay (CETSA). Finally, functional validation of Rh2's target specificity was achieved through transfection of PAFR overexpression or knockdown plasmids into chondrocytes. In the chondrocyte OA model, Rh2 treatment significantly suppressed PAFR expression and inhibited the NF-κB signaling pathway, resulting in the significant downregulation of key pyroptosis-related proteins, including NLRP3, cleaved Caspase-1, and GSDMD-N, as well as a decrease in the secretion of pro-inflammatory cytokines IL-1β and IL-18. These effects collectively attenuated chondrocyte pyroptosis and protected cartilage cells. Conversely, PAFR overexpression completely abolished the protective effects of Rh2, demonstrating the critical role of PAFR in mediating Rh2's therapeutic actions. Using a human chondrocyte cell line (C-28/I2) and focusing on PAFR as the target gene, our findings demonstrate that Rh2 alleviates chondrocyte pyroptosis in vitro by specifically targeting PAFR to suppress NF-κB signaling. These results provide a mechanistic basis for further investigation of Rh2 in more complex OA models. The PAFR/NF-κB axis represents a candidate pathway for cartilage protection.