Abstract: BACKGROUND: “Ruxiang-Moyao”  is a common combination of traditional Chinese medicine in the clinical treatment of knee osteoarthritis. However, the pharmacological mechanism is not yet clear. 
OBJECTIVE: Using network pharmacology technology to explore the therapeutic target of “Ruxiang-Moyao” as a commonly used traditional Chinese medicine for clinical treatment of arthromyodynia in the treatment of knee osteoarthritis and the relevant mechanism. 
METHODS: The chemical constituents of “Ruxiang-Moyao” were collected by TCMSP pharmacology database and analysis platform, and the possible bioactive constituents of frankincense and myrrh were screened according to the biological oral availability ≥ 30% and class drug properties ≥ 0.18. The possible targets of each active constituent were screened out using the protein database (Uniprot). GeneCards, OMIM, TTD and DrugBank databases were consulted to mine knee osteoarthritis-associated gene targets. The disease-drug protein target genes were obtained after the intersection of the above-mentioned screening data. The STRING database calculation and analysis algorithm was used to screen out important key genes to build a protein-protein interaction network, and the key target genes were uploaded to the PPI network graph. Cytoscape software was used to map the drug-target and disease-target visualization network, and DAVID online tool was further used for gene ontology (GO) analysis and Kyoto Encyclopedia of Genes and Gnomes (KEGG) pathway enrichment analysis. 
RESULTS AND CONCLUSION: Eight bioactive constituents of frankincense and 45 bioactive constituents of myrrh were obtained. At the same time, 412 target proteins of “Ruxiang-Moyao,” 1889 genes related to knee osteoarthritis and 105 co-targets of drugs and diseases were detected. The protein-protein interaction network found that AKT1, TP53, IL6, TNF, JUN, and MAPK1 might be the key targets of  “Ruxiang-Moyao” in the treatment of knee osteoarthritis. The GO enrichment analysis identified 66 GO items, which are involved in cell response to hypoxia, negative regulation of epithelial cell proliferation, immune response, insulin-stimulated cell response, and positive regulation of fibroblast proliferation. The enrichment analysis of KEGG pathway identified 95 related signaling pathways, which are involved in inflammation, cell apoptosis and cell senescence. David enrichment analysis showed that the key target of “Ruxiang-Moyao” intervention for knee osteoarthritis was mainly related to several biological processes such as inflammatory response, cell apoptosis and immune system. Overall, “Ruxiang-Moyao” has the characteristics of multi-pathway and multi-target action in the treatment of knee osteoarthritis, and mainly has anti-inflammatory and analgesic effects. The key targets of its action and the involved biological process and signaling pathway have been preliminarily revealed, providing a new idea for the clinical prescription treatment of knee osteoarthritis in the future.

Key words: knee, knee osteoarthritis, frankincense, myrrh, network pharmacology, pathway, protein, gene, mechanism