Anti-pruritic and anti-inflammatory effects of dihydromyricetin in a mouse model of allergic contact dermatitis

Abstract

Abstract Background Allergic contact dermatitis (ACD) is a highly prevalent inflammatory disease of the skin with limited treatment options. Its pathogenesis is believed to be driven by activation of inflammasome induced by allergens and irritants. Dihydromyricet(DHM) is a wild woody vine extract of Vitis viridis in the family Vitis. The main active ingredient is flavonoids, which exhibita wild range of pharmacological effects such as anti-inflammation and anti-oxidation. In this study, we investigated the anti-inflammatory and antipruritic effects of DHM and its mechanism in ACD mouse models. Methods Sixty ICR male mice were randomly divided into control group, DHM-treated control group (250 mg· kg-1), ACD model group, and three DHM-treated ACD groups (50, 150, 250 mg· kg-1). To induce ACD, 1-fluoro-2, 4-dinitrofluorobenzo (DNFB) was applied to the neck surface of ICR mice, which were treated with DHM by gavage. Cervical skin changes and scratching behaviors were recorded. HE staining was used for pathological observation, immunohistochemistry and western blot were used to determine the expression level of spinal cord glial cells, and Real-time qPCR was used to determine the level of local and central cytokines. Results DHM treatment significantly reduced skin inflammation and scratching episodes. It repaired epidermal keratinization and inflammatory cell infiltration in ACD mice. DHM treatment inhibited the activation of microglia and astrocytes to a certain extent. In addition, it reduced toll-like receptor (TLRs) 4 protein expression levels. At the same time, it significantly reduced the mRNA expression levels of TNF-α, IL-1β and IL-6 in local area and in central area. Conclusion This study demonstrates that DHM exhibits anti-pruritus and anti-inflammatory effects in ACD mice by modulating inflammatory mediators. DHM may be a potential treatment for itching and skin inflammation in patients with ACD.