Protective roles of genistein and icaritin in skin barrier integrity and hydration in an atopic dermatitis model

Introduction

Atopic dermatitis (AD) is a common chronic skin condition that primarily affects children and is characterized by impaired skin barrier function. Factors such as immune dysregulation and filaggrin deficiency contribute to barrier dysfunction. This study investigates the protective effects of genistein and icaritin in an AD-like model, focusing on their impact on skin barrier integrity, hydration, tight junction stability, and antimicrobial peptide production.

Methods

Human epidermal keratinocytes (HaCat cells) were cultured in Dulbecco’s modified Eagle medium with 10 % FBS and 1 % penicillin-streptomycin at 37 °C in 5 % CO₂ for 24 h. For the MTT assay, cells were plated at 1 × 10⁵ cells per well and treated with various concentrations of icaritin, genistein, their combinations, and dexamethasone. We established an AD-like inflammation model by treating the HaCat cells with TNF-α + IFN-γ (5 ng/ml), followed by extracting RNA and performing qRT-PCR using SYBR TOPreal, with GAPDH as the reference gene. The data are expressed as mean±S.D. (n = 3).

Results

Icaritin (6.25 and 12.5 μg/ml) and genistein (6.25 and 12.5 μg/ml) demonstrated no cytotoxic effects on HaCaT cells. Treatment significantly upregulated the expression of barrier-related genes, including filaggrin (FLG) with a fold change of 1.17 (genistein, 6.25 μg/ml, p < 0.01) and 1.16 (12.5 μg/ml, p < 0.05), Claudin-1 (0.75 (icaritin, 12.5 µg/ml, p < 0.001), and ZO-1 expression was significantly upregulated (1.79-fold) following combined treatment (p < 0.001). Furthermore, hyaluronic acid synthases (HAS-1, 1.66; HAS-2, 1.23) and hBD3 (1.98 at combined treatment) were notably increased.

Conclusion

Genistein and icaritin significantly enhance skin barrier integrity and hydration in HaCaT cells, upregulating key proteins including filaggrin and aquaporin 3, indicating their therapeutic potential in AD management.