Exploring the Effect of Xiao-Chai-Hu Decoction on Treating Psoriasis Based on Network Pharmacology and Experiment Validation

Background: Psoriasis is a chronic, inflammatory and recurrent skin disease. Xiao-Chai-Hu Decoction (XCHD) has shown good effects against some inflammatory diseases and cancers. However, the pharmacological effect and mechanisms of XCHD on psoriasis are not yet clear. Objective: To uncover the effect and mechanisms of XCHD on psoriasis by integrating network pharmacology, molecular docking, and in vivo experiments. Methods: The active ingredients and corresponding targets of XCHD were screened through Traditional Chinese Medicine Systems Pharmacology Database and Analysis (TCMSP) and Traditional Chinese Medicine Integrated Database (TCMID). Differentially expressed genes (DEGs) of psoriasis were obtained from the gene expression omnibus (GEO) database. The XCHD-psoriasis intersection targets were obtained by intersecting XCHD targets, and DEGs were used to establish the “herb-active ingredient-target” network and Protein-Protein Interaction (PPI) Network. The hub targets were identified based on the PPI network by Cytoscape software. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were performed next. Molecular docking was executed via AutoDockTools-1.5.6. Finally, in vivo experiments were carried out further to validate the therapeutic effects of XCHD on psoriasis. Results: 58 active components and 219 targets of XCHD were screened. 4 top-active components (quercetin, baicalein, wogonin and kaempferol) and 7 hub targets (IL1B, CXCL8, CCND1, FOS, MMP9, STAT1 and CCL2) were identified. GO and KEGG pathway enrichment analyses indicated that the TNF signaling pathway, IL-17 signaling pathway and several pathways were involved. Molecular docking results indicated that hub genes had a good affinity to the corresponding key compounds. In imiquimod (IMQ)-induced psoriasis mouse models, XCHD could significantly improve psoriasis-like skin lesions, downregulate KRT17 and Ki67, and inhibit inflammation cytokines and VEGF. Conclusion: XCHD showed the therapeutic effect on psoriasis by regulating keratinocyte differentiation, and suppressing inflammation and angiogenesis, which provided a theoretical basis for further experiments and clinical research.