To explore the potential mechanism of intervention on the immune imbalance of atopic dermatitis (AD) by studying the effects of Mahuang Lianqiao Chixiaodou decoction (MLCD) on skin damage and inflammation factors in an AD-like mouse model.

Ninety-six male BALB/c mice were divided into normal, model, positive control (mometasone furoate), and traditional Chinese medicine treatment (MLCD) groups by a random number table. 2,4-dinitrofluorobenzene was used to induce AD-like mice in all groups except the normal group. The treatment or intervention was administered for seven consecutive days on days 4, 18, 32, and 39. The mRNA relative expressions of interleukin-4 (IL-4), IL-10, interferon-γ (IFN-γ), thymic stromal lymphopoietin (TSLP), and the TSLP receptor (TSLPR) were measured using quantitative real-time polymerase chain reaction, and the serum immunoglobulin E, IL-4, IL-10, and IFN-γ levels were detected using enzyme-linked immunosorbent assay.

Compared with the normal group, the hematoxylin-eosin staining of the skin lesions of the mice in the model group was significantly thickened on days 11, 25, and 39. Compared with the model group, the epidermal thickness of the positive control group was significantly alleviated on day 39 (P < .001), and that of the MLCD group was significantly improved on days 25 and 39 (P < .001). Compared with the four observation time points, MLCD had the best treatment effect on day 39 of the experiment and significantly improved the skin damage performance and relieved pathological lesions. On day 39, compared with the model group, MLCD downregulated the skin mRNA relative expressions of IL-4 (P = .009), TSLP (P = .030), and TSLPR (P < .001), and reduced the mouse serum levels of IL-4 (P = .003). For other serum indicators, no significant difference was observed between the model and MLCD groups.

MLCD improved AD-like mice skin damage by regulating the Th1/Th2 immune imbalance.

To reveal the mechanism of Mahuang Lianqiao Chixiaodou decoction and its disassembled formula for improving the skin barrier function in a mouse model of atopic dermatitis (AD).

Sixty specific-pathogen free male BALB/c mice were randomly divided into the control group, model group, whole formula group (WF), exterior-releasing formula group (ERF), interior-clearing formula group (ICF), and positive control group (PC). A mouse model of AD was established using the semi-antigen 2, 4-dinitrofluorobenzene induction method. The lesion scores, transepidermal water loss and pH, and skin histopathology of mice in each group were observed. The expressions of filaggrin, loricrin, and involucrin were detected by the streptavidin peroxidase immunohistochemical method and western blotting, and their mRNA expressions were detected by quantitative polymerase chain reaction.

Mice in the WF, ERF, ICF, and PC groups showed reduced skin lesion performance, improved histopathology, decreased skin lesion score, transepidermal water loss and pH, and upregulated expressions of proteins including filaggrin, loricrin, and involucrin, and their mRNAs. The most obvious regulatory effect was observed in the WF group, followed by the ICF, ERF, and PC groups, accordingly.

Mahuang Lianqiao Chixiaodou decoction and its disassembled formula can improve the skin barrier function in a mouse model of AD by upregulating filaggrin, loricrin, and involucrin, and their mRNA expressions, and the most optimal effect was noted in the WF group, followed by the ICF and ERF groups, which suggests that the effect of clearing heat and resolving dampness in improving the skin barrier function of AD is more obvious and is one of the key treatments for AD.