Matrine alleviates imiquimod-induced psoriasiform dermatitis in BALB/c mice via dendritic cell regulation

Matrine, is a bioactive compound isolated from Sophora flavescens (Ku shen), an herb used in Chinese traditional medicine that possesses wide-reaching pharmacological action. Psoriasis is a chronic relapsing inflammatory disorder with an incompletely understood pathophysiology, and dendritic cells (DCs) play a central role in the disease. This study aimed to explore DCs related potential mechanisms based on the effect of matrine on imiquimod (IMQ)-induced psoriasiform dermatitis in BALB/c mice and DCs simulated by resiquimod. Mice with IMQ-induced psoriasiform cutaneous lesions were treated with matrine [12.5, 25 or 50 mg/(kg·d), for 6 days]. Morphology, histological changes, keratinocyte proliferation and differentiation, inflammatory cell infiltration, protein expression levels of myeloid differentiation factor 88 (MyD88), and mRNA expression levels of inflammatory factors [interleukin (IL)-12, IL-23, and IL-1β] in lesional skin were assessed. The application of matrine decreased the proliferation of IMQ-induced keratinocytes. The treatment attenuated the infiltration of PCNA⁺ and CD3⁺ cells in the lesions. Matrine reduced the expression of the MyD88 protein and the inflammatory factors' mRNA in lesional skin, but also in BMDCs (bone marrow derived dendritic cells). These results indicated that matrine suppressed expression of the inflammatory factors by decreasing the expression of the MyD88 protein on the surface of BMDCs, finally alleviating psoriasiform skin lesions. Therefore, the findings suggest that matrine might be a potential candidate for treating psoriasis.