Establishment of Psoriasis Mouse Model by Imiquimod

Psoriasis is a common, chronic, relapsing, and inflammatory skin condition characterized by thickened skin infiltration, scales, and erythema. The pathogenesis of the disease is highly complex, involving the interplay of various factors such as genetics, immunity, and environmental factors. To investigate the mechanisms underlying psoriasis, researchers have developed multiple animal models of the disease. However, the variability in methodologies has presented challenges for constructing these models consistently. In this study, we established and comprehensively evaluated a highly efficient and stable psoriasis mouse model using imiquimod (IMQ). 8-week-old SPF-grade female C57BL/6J mice were used to establish the psoriasis mouse model. After one week of acclimatization, mice with irritated or damaged skin in the depilated areas were excluded. Starting on day two, 5% IMQ cream (62.5 mg/d) was applied daily to the depilated neck and back regions for seven consecutive days. During the experiment, daily measurements of body weight, skin photography, skin scoring, and behavioral observations were conducted. Post-experiment, spleen index determination, skin histological analysis, serum cytokine detection, and skin mRNA level detection were performed. The results showed that mice in the IMQ group developed typical psoriasis-like symptoms, including erythema, scales, and skin thickening, accompanied by increased scratching behavior, weight loss, elevated spleen index, and increased skin thickness. And significant changes in the levels of TNF-α, IL-23, and IL-17A in serum, as well as the mRNA levels of IL-23, IL-17A, IL-17F, and IFN-γ in the skin. Serum cytokine levels (TNF-α, IL-23, IL-17A) and skin mRNA expression of pro-inflammatory markers (IL-23, IL-17A, IL-17F, IFN-γ) were notably upregulated. In contrast, the control group exhibited no such alterations. By optimizing the IMQ induction duration and standardizing the administration protocol, while dynamically monitoring skin changes, this study aims to provide a standardized framework for researchers to construct reliable psoriasis models.