Hataedock treatment has preventive therapeutic effects for atopic dermatitis through skin barrier protection in Dermatophagoides farinae-induced NC/Nga mice

Abstract

Ethnopharmacological relevance: Hataedock treatment is traditionally used for the purpose of preventing the future skin disease by feeding herbal extracts to the newborn in traditional Chinese and Korean medicine.

Aim of the study: This study investigated the preventive therapeutic effects of Hataedock (HTD) treatment for atopic dermatitis (AD) through skin barrier protection in Dermatophagoides farinae-induced NC/Nga mice.

Materials and methods: To the HTD treatment group, the extract of Coptis japonica Makino and Glycyrrhiza uralensis Fischer, which analyzed with High Performance Liquid Chromatography (HPLC)-fingerprint for quality consistency, was administered orally to the 3-week-old mice before inducing AD. After that, Dermatophagoides farinae was applied except the control group to induce AD-like skin lesions. We confirmed the effects of HTD on morphological changes, protection of skin barrier, regulation of Th2 differentiation, inflammation regulation and induction of apoptosis through histochemistry, immunohistochemistry, and Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay.

Results: HTD effectively reduced edema, angiogenesis and skin lesion. HTD also increased the levels of liver X receptor (LXR) and filaggrin but decreased the level of protein kinase C (PKC) (p<0.01). The levels of interleukin-4 (IL-4), IL-13, signal transducer and activator of transcription-6 (STAT-6) and Cluster of differentiation 40 (CD40) were significantly reduced in the HTD treated group (p<0.01). HTD also suppressed the mast cell degranulation and the level of the high-affinity IgE receptor (FcɛRI), substance P, Matrix metalloproteinases-9 (MMP-9) and 5-hydroxytryptamine (5-HT) (p<0.01). The levels of inflammatory factors such as nuclear factor-kappaB (NF-κB) p65, phosphorylated IκB (p-IκB) and inducible nitric oxide synthase (iNOS) were also decreased (p<0.01). Apoptosis of inflammatory cells was also found to increase (p<0.01).

Conclusion: Our results indicate that HTD effectively regulate the Th2 differentiation, mast cell activation and various inflammatory responses on AD-induced mice through protection of skin barrier. Therefore, HTD may have potential applications for alternative and preventive treatment in the management of AD.

Keywords: Atopic dermatitis; Dermatophagoides farina; Hataedock; Skin barrier protection; anti-inflammation; outside-in hypothesis.