2.3. Experimental design

One week after STZ injection, mice were randomly divided into four groups (n = 6), two groups that received Vaseline ointment (NCD + Vaseline and DM + Vaseline), and two groups that received imiquimod (IMQ)‐induction (NCD + IMQ and DM + IMQ). A 3 × 4 cm² area on the back of each mouse was shaved and treated with Vaseline ointment or IMQ cream (62.5 mg/animal) for seven consecutive days. After the experiment, the mice were sacrificed, and blood samples were collected from their hearts. Skin tissue was isolated from the anaesthetized mice and stored at −80°C, and a part of each tissue sample collected was fixed in paraformaldehyde for histopathological analysis as described in Section 2.5.

The other mice were randomly divided into three groups (n = 6): Vaseline ointment group (NCD + Vaseline) and IMQ‐induction group (DM + IMQ and DM + IMQ + C‐176). Before IMQ‐induced psoriasis‐like skin inflammation, the DM + IMQ + C‐176 group was injected with 7.5 μL (750 nmol) of C‐176 per mouse or DMSO dissolved in 85 μL corn oil once per day for 2 weeks. The dosage and time points of C‐176 were based on a previous study. 25 The mice were then shaved and treated with IMQ cream or Vaseline ointment, as previously described.