Effects of topical application of realgar on pruritus and inflammation of atopic dermatitis

Abstract

Objectives: Realgar has been frequently used for skin disorders in history of herbal medicine. However, the efficacy of realgar has not been examined in atopic dermatitis(AD). In this study, the effects of realgar on AD were investigated, especially on pruritus and inflammation. Methods: AD lesions were induced in the shaved backs of BALB/c mice through repeated application of DNCB. The mice were treated for 11 days with 1% realgar (100 μL/day). Histological changes in skin thickness were observed. The anti-pruritic effects of realgar were evaluated by the change in numbers of scratching behavior of mice and expression of substance P. The expressions of cytokines IL-4 and IL-6 were measured. Also, anti-inflammatory effects of realgar were examined on expressions of NF-κB, phospho-IκBα and mitogen-activated protein kinases (MAPKs).Realgar decreased skin thickness (both dermal and epidermal) 38% and 17% respectively, compared to positive control, DNCB group. The scratching behavior of mice was reduced by 42% and expression of substance P was significantly less. Cytokines IL-4 and IL-6 were significantly reduced by 52.6% and 77.6%, respectively. The expressions of NF-κB, phospho-IκBα and MAPKs (phospho-ERK1/2, -p38 and -JNK) were significantly suppressed with marked effects on phospho-ERK1/2. Conclusions: The collective results suggest that realgar shows anti-pruritic and anti-inflammatory effects on AD. And realgar might be a potential therapeutic candidate for treatment of atopic dermatitis.