Imiquimod-Induced Psoriasis (Rats and Mice)

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Psoriasis is the most prevalent immune-mediated skin disease in adults, and affects approximately 25 million people in North American and Europe alone¹. Psoriasis is a complex, multifactorial disease and the exact mechanism of psoriasis is not yet fully understood^1,2. In the past, most psoriasis research was performed in a xenotransplant model, where skin from a psoriasis patient is grafted onto immunodeficient mice. Although this model is useful, these experiments are laborious, expensive, and require considerable expertise and technical skill^3,4. The development of the imiquimod-induced model of psoriasis is a simple, acute, cheap model that has been used with increasing frequency to better understand the inflammatory process leading to psoriasis, as well as a high-throughput screening of potential therapeutic agents^3,5.

Induction:

Starting on Study Day 0 and continuing daily for the duration of the study, 75mg (mice) or 150mg (rats) of 5% imiquimod cream is applied to the shaved skin on the back.

Disease Parameters/Progression:

In mice, redness and scaling significantly increase by Study Day 6; whereas visual thickening score and caliper measurements increase at day 4.

Dosing Paradigms:

Prophylactic (Developing) – Dose prior to daily IMQ.
Established (Therapeutic) – Dose after IMQ.
Route of administration: Topical, SC, PO, IP, IV

Clinical Assessment:

PASI Scoring
Every other day animals are scored for erythema, scaling, and skin thickening as follows:

0 = None
1 = Slight
2 = Moderate
3 = Marked
4 = Very Marked

Skin caliper measurements are also taken every other day using a Digitrix II micrometer. Biopsy punches of the skin may also be taken and weighed.

Sample Data (Click on image to enlarge):

Mouse Clinical

Mouse Photographs

Naive

Imiquimod+Clobetasol

Imiquimod

Rat Clinical

Rat Photographs

Naive

Imiquimod+Clobetasol

Imiquimod

Notes:

The imiquimod-induced model of psoriasis is a simple model that has been used with increasing frequency to better understand the inflammatory process leading to psoriasis, as well as a high-throughput screening of potential therapeutic agents.

Optional Endpoint

PK/PD blood collections
Cytokine/chemokine analysis via Luminex(R)
Other sandwich ELISAs
CBC/clinical chemistry analysis
Histopathologic analysis
Immunohistochemistry analysis

References

Sun J, Zhao Y, and Hu J. Curcumin inhibits imiquimod-induced psoriasis-like inflammation by inhibiting IL-1beta and IL-6 production in mice. PLoS ONE. 2013; 8(6):e67078.
Pantelyushin S, et al. Rorγt+ innate lymphocytes and γδ T cells initiate psoriasisiform plaque formation in mice. The Journal of Clinical Investigation. 2012; 122(6):2252-2256.
Flutter, B and Nestle FO. TLRs to cytokines: mechanistic insights from imiquimod mouse model of psoriasis. Eur. J. Immunol. 2013; 43:3138-3146.
Van der Fits L, et al. Imiquimod-induced psoriasis-like skin inflammation in mice is mediated via the IL-23/IL-17 Axis. J-Immunol. 2009; 182:5836-5845.
Swindell WR, et al. Genome-wide expression profiling of five mouse models identifies similarities and differences with human psoriasis. PLoS ONE. 2011; 6(4):e18266.

For more information about IMQ-Induced Psoriasis (Mice and Rats), c ontact us here.

General Inflammation