1.2 K14-VEGF-A-Tg mouse psoriasis model and therapy
All animal experiments were performed in accordance with the National Research Council’s Guide for the Care and Use of Laboratory Animals. K14-VEGF-A-Tg homozygous mice overexpressing VEGF in the epidermis were used for the experiments, and these mice spontaneously developed a chronic inflammatory skin disease with many features similar to those observed in human psoriasis (Xia, Li, Hylton, Detmar, Yancopoulos & Rudge, 2003). These mice were provided by Professor Jiong Li from the State Key Laboratory of Biotherapy and Cancer Center (Chengdu, China). K14-VEGF-A-Tg homozygous mice (10 weeks old, psoriasis-like symptoms began to appear) were randomly assigned to two groups (n = 5 per group). Each mouse was subjected to a total of 10 intravenous (i.v.) injections of either phosphate-buffered saline (PBS) (control) or 5 μg IL-35 recombinant protein (10705-H02H, Sino Biological, Beijing, China) every other day. At 24 h after the last injection, the animals were anaesthetised using 50 μL of chloral hydrate (10 %; intraperitoneal injection, Tianjin Regent Chemicals Co., LTD, Tianjin, China) for macroscopic photography. The animals were then euthanised, and psoriatic lesion tissues were collected. All procedures were performed at the Jining Medical University.