L citrulline

For the IMQ-induced mouse model of psoriasis, male C57BL/6 mice (7 weeks-of-age) purchased from Shanghai SLAC Laboratory Animal Co. (Shanghai, China) were maintained under SPF conditions. The mice were subjected to a daily topical dose of 62.5 mg IMQ cream (5%) (MedShine cat. 120503) on the shaved back or 20 mg per ear for six consecutive days. On the indicated days, the skin thickness was measured with a micrometer (Schieblehre). The control mice were treated with an equivalent dose of vehicle cream. For the metabolite treatment, L-Arginine (Sangon Biotech cat.
A600205, 5 mg/ml), L-Ornithine (Sigma-Aldrich cat. O6503, 4 mg/ml), L-Proline (Sangon Biotech cat. A600923, 4 mg/ml), Creatine (Sangon Biotech cat. A600326, 10 mg/ml), L-Citrulline (Sangon Biotech cat. A604057, 5 mg/ml) and Spermidine (Sigma-Aldrich cat. S0266, 2 mg/ml) were added to the drinking water 7 days prior to the IMQ application and the treatment lasted until the end of model establishment. application. An equal volume of PBS was injected to the contralateral shoulder of the monkey. The clinical scores of the skin phenotype were graded according to Lattice System Physician's Global Assessment (Langley and Ellis, 2004) .