Integrated proteomic and metabolomic analysis reveals the potential therapeutic mechanism of Quanduzhong capsule in rats with spontaneous hypertension and knee osteoarthritis

Quanduzhong capsule (QDZ), derived from Eucommia ulmoides Oliv., has been traditionally used in Chinese medicine for its beneficial effects on musculoskeletal health. Its clinical application has extended to conditions such as spontaneous hypertension combined with knee osteoarthritis (SKOA). However, the specific mechanisms by which QDZ alleviates symptoms and improves outcomes in this complex condition remain to be fully elucidated. This study aims to evaluate the therapeutic potential of QDZ in treating SKOA. By performing serum proteomics and metabolomics, we seek to explore the related biological pathways and elucidate the mechanisms underlying QDZ's effects on SKOA. Serum samples from control, spontaneous hypertension (SHR), SKOA, and SKOA treated with QDZ groups were analyzed using data-independent acquisition-based proteomics to identify differentially expressed proteins. Serum levels of angiotensin II, norepinephrine, endothelin-1, classical pro-inflammatory factors such as macrophage colony-stimulating factor, tumor necrosis factor-alpha, and interleukin-1 beta were measured. Additionally, serum metabolomics was performed to examine the changes in metabolite profiles. Correlation analysis was conducted to link changed proteins and metabolites with key pathways affected by QDZ. Proteomics analysis revealed significant alterations in serum protein expression between control, SHR, and SKOA groups, with changes in pathways related to immune regulation and vascular function. KEGG enrichment analysis highlighted pathways such as endocytosis, synaptic vesicle cycling, and immune responses were enriched in SKOA group compared with control group. QDZ treatment significantly modulated above pathways and reduced inflammatory and cardiovascular markers which were upregulated in SKOA group. Metabolomics analysis showed that QDZ reversed SKOA-induced changes in amino acid and organic acid metabolism, affecting pathways including valine, leucine, and isoleucine metabolism, as well as the TCA cycle. Correlation analysis revealed significant relationships between key proteins and metabolites, underscoring the integrated role of immune and metabolic pathways in QDZ's effects. Our results indicate QDZ has a significant therapeutic potential for SKOA by modulating both protein and metabolite profiles associated with inflammation, vascular dysfunction, and metabolic imbalance. Our findings provide insights into the mechanisms through which QDZ exerts its effects and