A Localized Aldara (5% Imiquimod)–Induced Psoriasiform Dermatitis Model in Mice Using Finn Chambers

Abstract

The expanding number of research studies utilizing the imiquimod‐induced psoriasiform dermatitis model attests to the usefulness of this procedure. Advantages of this model include rapid development of the skin response and cost‐effectiveness. A major limitation is that application of imiquimod cream over large areas of skin, as well as licking and ingestion of the cream, may lead to severe systemic inflammation, which can cause a general decline in health, splenomegaly, and death. In this protocol, Finn chambers are used to localize the imiquimod cream to a small area of the skin. This results in production of severe and reproducible psoriatic skin reactions with significantly less imiquimod, greatly reducing the possibility of untoward systemic effects. Moreover, having psoriasiform and control skin areas on the same mice decreases inter‐animal differences. The protocol can be readily adapted for other skin disease models involving topical application of test agents. This article also details functional measurements performed during assays, including skin thickness, blood perfusion, semiquantitative histopathological evaluation, determination of scaling score to monitor psoriatic symptoms, and collection of spleen and body weight data to identify systemic effects. © 2020 The Authors. Basic Protocol: Use of Finn chambers to induce psoriasiform skin reactions with imiquimod Support Protocol 1: Measurement of double‐fold dorsal skin thickness Support Protocol 2: Measurement of blood perfusion Support Protocol 3: Determination of scaling score Support Protocol 4: Semiquantitative histopathological scoring Support Protocol 5: Assessment of systemic side effects in response to imiquimod application

Characterization and ex vivo evaluation of excised skin samples as substitutes for human dermal barrier in pharmaceutical and dermatological studies

“…For comparison, an epilated pig skin was also tested. A diseased mouse skin of a chemically induced psoriasis model 26 , 27 , 28 was investigated as well (5% Aldara treatment for 96 h), but this sample (contrary to the others) had been previously frozen and thawed (Figure 4 ).…”

Desmoglein-4 Deficiency Exacerbates Psoriasiform Dermatitis in Rats While Psoriasis Patients Displayed a Decreased Gene Expression of DSG4

“…Although the mice model has been clearly adopted as an IMQ-experimental psoriasis, the rat model has not yet been studied in detail. Indeed, splenomegaly, a psoriasis-related systemic disorder that has been reported in the IMQ-induced mouse model of psoriasis, has not been studied at all in the rat model ( 34 ). In contrast to what has been in the mice model, our findings suggest that topical administration of IMQ in SD rats does not lead to spleen or lymph node enlargement.…”

TAZ deficiency exacerbates psoriatic pathogenesis by increasing the histamine-releasing factor

“…TAZ KO mice were generated by a strategy of deleting the second exon and homozygous KO males were crossed with heterozygous females to ensure sufficient numbers of KO mice [ 14 , 16 ]. WT and TAZ KO mice (male, 8‒10 weeks old, 22‒25 g) were divided into the vehicle- and IMQ-treated groups and shaved on the back, followed by daily topical treatment with 62.5 mg of 5% IMQ (Aldara cream, 3 M Pharmaceuticals) or control cream [ 34 ]. IMQ was also applied daily to the right ear pinna of the mice for 7 consecutive days, as previously reported [ 35 ].…”