1042 Characterizing Imiquimod (IMQ)-induced psoriasis-like dermatitis in BALB/c mice: Application in dermatology research

Psoriasis is a common inflammatory skin disease that has limited topical treatment options. Several mouse models have been created to mimic psoriasis-like skin. In particular, the imiquimod (IMQ)-induced psoriasis-like skin model has been a useful tool to test therapeutic applicability of various topical agents. Despite its widespread use in research, the IMQ mouse model itself has not been well characterized and researchers would benefit from a better understanding of the induction, expected duration, and re-induction of topically-applied IMQ on mouse skin. In our experiment using BALB/c mice, we have shown that the IMQ-induced psoriasis-like skin reaction begins within the first 2 days of once daily induction, and continues for 5 days. It fails, however, to sustain the same intensity of reaction beyond 5 days. After day 5, regardless of whether IMQ is applied daily or on alternating days, the normalization process begins and the reaction is not sustained. By day 10, the skin regains normal appearance phenotypically and histologically. Once normalized, the IMQ-induced psoriasis-like skin reaction can then be re-induced in the same mouse with re-application of IMQ in the same manner. Overall, we characterize the IMQ-induced psoriasis-like mouse model for application in dermatology research.