FoxO1/PINK1/Parkin-dependent mitophagy mediates the chondroprotective effect of Guzhi Zengsheng Zhitong decoction in osteoarthritis.

Guzhi Zengsheng Zhitong Decoction (GZZD) is a classic traditional Chinese medicine (TCM) prescription for treating knee osteoarthritis (OA), and has been widely used in clinical practice in China. Given that Forkhead box protein O 1 (FoxO1) has been identified as a potential therapeutic target for OA treatment, this study investigates the chondroprotective effects of GZZD through FoxO1-mediated mitochondrial regulation, bridging traditional medicine with contemporary molecular insights. The therapeutic effects of GZZD on OA and its chondroprotective mechanisms were evaluated both in vivo and in vitro. A rat model of knee OA was established by intra-articular injection of monosodium iodoacetate (MIA), while an in vitro OA model was induced by IL-1β stimulation in chondrocytes. Histological staining, immunohistochemistry, and Western blot analyses were performed to assess cartilage protection. Serum ingredients of GZZD were identified using LC-MS/MS, and the core pathways involved in GZZD-mediated chondroprotection were explored through transcriptomics and network pharmacology. Key protein expression was examined, and molecular biology techniques were applied to validate the role of FoxO1 and its downstream pathways in regulating chondrocyte autophagy, apoptosis, and mitochondrial dysfunction. Additionally, molecular docking and molecular dynamics simulations were conducted to analyze interactions between bioactive compounds and FoxO1. GZZD significantly ameliorated MIA-induced knee joint damage, reduced cartilage degradation and subchondral bone destruction, and decreased OARSI scores. Treatment with GZZD markedly decreased serum levels of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) while enhancing protective autophagy in chondrocytes. Furthermore, GZZD inhibited chondrocyte apoptosis and mitochondrial dysfunction, accompanied by the upregulation of the cartilage matrix protein COL2A1 and the anti-apoptotic protein BCL2, along with downregulation of catabolic factors (MMP13, IL-1β). Mechanistically, GZZD activated the FoxO1/PINK1/Parkin pathway, restoring mitochondrial homeostasis and mitigating mitochondrial-dependent apoptosis, ultimately protecting chondrocytes from OA-related damage. For the first time, this study demonstrates that the traditional Chinese medicine formula GZZD alleviates osteoarthritis by activating the FoxO1/PINK1/Parkin pathway, thereby restoring mitochondrial function and protecting chondrocytes from injury. These findings not only establish GZZD as a promising complementary therapy for OA but also provide a scientific foundation for developing FoxO1-targeted therapeutics.