The Effect and Mechanism of Burnet Gels on Steroid-Dependent Dermatitis in Guinea Pig Model

OBJECTIVE: This study was designed to establish quality standards of Burnet gels and investigate the effects and mechanism of Burnet gels on steroid-dependent dermatitis (HDD) in guinea pigs. METHODS: HPLC was used to determine the content of gallic acid, Gentiopicrin, and paeonol. A total of 48 male guinea pigs were recruited and randomly divided into control group, model group, tacrolimus ointment group, and Burnet gel group (Low, medium, and high concentration). The HDD guinea pig model was established by the 0.5% clobetasol propionate tincture. After HDD model establishment, control group and model group smeared normal saline and the rest of the group with corresponding drugs for three weeks. The contents of IFN-γ, IL-4, and IgE in the guinea pig serum were detected by the ELISA; the protein expression levels of FLG, LOR, and Caspase-14 in the epidermis of guinea pigs were detected by the immunohistochemical and Western blotting method. RESULTS: The content of gallic acid, Gentiopicrin, and paeonol was 0.30 mg/g, 1.06 mg/g, and 0.56 mg/g. Compared with the normal group, the IFN-γ, IL-4, and IgE of guinea pig serum in the model group were significantly increased; the FLG, LOR, and Caspase-14 of guinea pig epidermis in the model group were significantly decreased; compared with the model group, the IFN-γ, IL-4, and IgE of guinea pig serum in the tacrolimus ointment group and Burnet gel group were significantly decreased; the FLG, LOR, and Caspase-14 of guinea pig epidermis in the tacrolimus ointment group and Burnet gel group were significantly increased. CONCLUSION: Burnet gels can improve guinea pig HDD model, and the mechanism may be related to inhibiting skin inflammation and promoting the formation of epidermal skin barrier.