Abstract
Atopic dermatitis (AD) is a chronic, inflammatory cutaneous disorder. Obesity is associated with increased prevalence and severity of AD for reasons that remain poorly understood. Myricetin, a dietary flavonoid found in fruits and vegetables, is known to have anti-inflammatory effects, but its role in AD is unclear. Thus, we investigated the effects of obesity on exacerbation AD lesions, and evaluated the effects of myricetin on obese AD. Mice were fed normal diet (ND) or high-fat diet (HFD), and then 2,4-dinitrofluorobenzene (DNFB) was used to induce AD-like lesions. We found that obesity exacerbated AD lesions, and myricetin topical administration ameliorated symptoms and skin lesions of obsess AD mice such as dermatitis scores, scratching behavior, epidermal thickness and mast cell infiltration. In addition, myricetin reduced the levels of IgE and histamine, inhibited the infiltration of CD4+T cells and modulated the expression of Th1, Th2, Th17 and Th22 cytokines and pro-inflammatory factors (CCL17, CCL22, IL-1β, TGF-β). Moreover, myricetin restored impaired barrier function by reducing trans-epidermal water loss (TEWL), increasing lamellar body secretion, as well as up-regulating the mRNA and protein expression of filaggrin. Western blot results showed that significantly increased levels of phosphorylated IκB and NF-κB p65 was observed in the obese AD mice compared to the AD mice fed ND, while the myricetin could downregulated the phosphorylation of them, and inhibited mRNA expression of iNOS and COX2. Taken together, these results suggest that myricetin treatment exhibits potentially protective effects against the obese AD by inhibiting inflammatory response and restoring skin barrier function.
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