Therapeutic effects of quinine in a mouse model of atopic dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease that seriously affects quality of life. Quinine is a bitter taste receptor agonist that exhibits antimalarial effects. The aim of the present study was to examine the therapeutic effects of quinine in AD-like mice. AD was induced with 2,4-dinitrochlorobenzene, and the mice were treated with 10 mg/kg quinine for 1, 4 and 7 days. A total of 60 BALB/c mice were divided into the following groups: Healthy, AD-like, AD-like + quinine and healthy + quinine, with 1, 4 and 7 days groups for each treatment. Blood was extracted from all mice and ELISA was performed to detect immunoglobulin E (IgE) levels. H&E-stained tissue sections were prepared from skin lesions on the backs of the mice and pathological changes were observed. Cytokines were detected via ELISA, and the filaggrin (FLG) and kallikrein-7 (KLK7) proteins were detected via western blotting and immunohistochemistry. IKKα and NF-κB mRNA were analyzed via reverse transcription-quantitative PCR. Quinine ameliorated skin damage in the AD-like mice, reduced IgE expression in the blood, inhibited expression of IKKα and NF-κB, reduced cytokine secretion, reduced KLK7 expression, reduced scratching frequency, increased FLG expression and repaired the skin barrier. These results suggested that quinine exhibited therapeutic effects in AD-like mice.