Potential Supportive Effects of AP Collagen Peptides on Skin Hydration in a Mouse Model of Oxazolone-Induced Atopic Dermatitis.

Atopic dermatitis (AD) is a chronic and relapsing inflammatory skin disorder characterized by impaired skin barrier function and Th2-mediated immune responses. Collagen tripeptide (CTP), an amino acid-rich dietary supplement with low antigenicity, has been reported to improve skin hydration and barrier function. However, its therapeutic effects in AD, particularly under conditions of barrier dysfunction, have not yet been fully established. In this study, we evaluated the potential effects of AP collagen peptide (APCP), which contains CTP, on skin hydration and inflammatory responses, in an oxazolone (OXZ)-induced AD-like model using hairless mice. Skin hydration and transepidermal water loss (TEWL) were measured, while inflammatory responses were analyzed by histological evaluation and RT-qPCR. APCP-treated mice showed a tendency toward improvement in AD-like clinical symptoms and TEWL. In addition, APCP administration significantly increased skin hydration, accompanied by restoration of filaggrin expression and significantly reduced expression of TSLP, p-STAT3, and p-ERK. In contrast, mast cell infiltration, CD3+ and CD4+ T cell infiltration, and the expression of inflammatory cytokines, including IFN-γ, IL-4, IL-13, and IL-31, showed a tendency toward reduction but did not reach statistical significance. These findings suggest that APCP may not exert broad immunosuppressive effects, but may contribute to the alleviation of AD symptoms through improvements in skin hydration, supporting its potential as an adjunctive agent for AD.