Characterizing Imiquimod-Induced Psoriasis-like Dermatitis in BALB/c Mouse: Application in Dermatology Research

The imiquimod (IMQ)-induced psoriasis-like dermatitis mouse model is a powerful tool in psoriasis research. The model, however, has not been fully characterized for its optimal application in research. Our study aims to define the chronology of an IMQ-induced inflammatory skin reaction in BALB/c mouse with the goal of optimizing the induction protocol for future psoriasis research. We applied IMQ 5% cream on the skin of BALB/c mouse. Subsequently, the skin was harvested and processed for H&E staining and Ki67 immunostaining. Once daily topical application of IMQ on BALB/c mouse induced psoriasislike dermatitis clinically and histologically beginning on day 2 and peaking on days 4 and 5. Correspondingly, the topical application also induced a hyperproliferative epidermis in a similar fashion. These changes were acute in nature and not sustainable beyond day 5, despite continued application of IMQ. However, once the skin was allowed to recover completely back to baseline, then IMQ application was able to re-induce psoriasis-like dermatitis. Understanding how best to manipulate the model to meet the needs of an individual experimental design may help researchers to avoid unnecessary optimization processes and to obtain robust outcomes.