Paeoniflorin suppresses inflammatory response in imiquimod-induced psoriasis-like mice and peripheral blood mononuclear cells (PBMCs) from psoriasis patients

Psoriasis is one of the most common immune-mediated chronic inflammatory skin disorders, characterized by hyperproliferation of keratinocytes, dilation and growth of dermal capillary vasculature, and cellular infiltration of T cells, dendritic cells (DCs), and neutrophils. Paeoniflorin (PF), the principal component of total glucosides of paeony (TGP), displays anti-inflammatory and antioxidant properties in several animal models. In this study, we investigated the anti-inflammatory effects and mechanisms of PF in imiquimod (IMQ)-induced psoriasis-like mouse model. The effects of PF on inflammatory cytokine expression in peripheral blood mononuclear cells (PBMCs) from patients with psoriasis vulgaris were also observed. Our results indicated that PF effectively attenuated the clinical and histopathologic changes in IMQ-induced psoriasis-like mouse model. Furthermore, PF reduced the infiltration of T cells, CD11c(+)DCs, and neutrophils in lesional skin. In addition, PF also significantly decreased the mRNA expression of inflammatory cytokines, such as IL-17, INF-γ, IL-6, and TNF-α, in IMQ-induced psoriasis-like mouse model and PBMCs from patients with psoriasis vulgaris. Hence, our data suggest that PF can inhibit leukocyte infiltration and decrease the expression of inflammatory cytokines such as IL-17, INF-γ, IL-6, and TNF-α. PF might be a candidate drug for the treatment of psoriasis.