Imiquimod-induced psoriasis mouse model and in vivo treatment

Mice were topically administrated daily at a dose of 100 mg of 5% imiquimod cream on the shaved region of their back for seven consecutive days. Normal mice without any treatment were not stimulated by imiquimod cream. Two hours after imiquimod cream application, different types of MN patch per mice were topically applied on delimited back skin. The MN patch was pressed firmly for 60 s to penetrate through the stratum corneum and epidermis, and then the MN patch was pressed softly for an additional 30 s to make the patch absorb the liquid in the skin. The MN patch was further fixed using medical tape for further sustained drug release. Dex cream and tacrolimus ointment per mice per day were topically applied for 6 days. During the treatment, the PASI score was recorded as the sum of scores graded as 0 (no symptoms), 1 (mild), 2 (moderate), 3 (severe), or 4 (very serve) for each of the three measured symptoms (erythema, scaling, and induration). Erythema was graded using a scoring table with red tints. After 7 days, mice were sacrificed to obtain skin tissues and spleen. In the histologic analysis, the skin was fixed in 4% paraformaldehyde and stained with H&E for microscopic observation.