Imiquimod-Induced Psoriasis (Rats and Mice)

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 understood1,2. 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 skill3,4. 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 agents3,5.

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

Rat Clinical

Rat Photographs

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

  1. 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.
  2. 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.
  3. Flutter, B and Nestle FO. TLRs to cytokines: mechanistic insights from imiquimod mouse model of psoriasis. Eur. J. Immunol. 2013; 43:3138-3146.
  4. 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.
  5. 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), contact us here.

Tell Us About Your Project! Get a Quote »