Protective Effect of Peony (Paeonia ostii) Flower Extract Against Tape Stripping-Induced Skin Barrier Impairment in Mice

<b>Background:</b> Skin barrier dysfunction leads to increased transepidermal water loss (TEWL), inflammation, and compromised skin protection. While <i>Paeonia ostii</i> (peony) flowers are recognized in traditional Chinese medicine for their reducing melanin synthesis, anti-inflammatory, and anti-aging effects, their role in repairing skin barrier damage has not been fully explored. <b>Methods:</b> We investigated the therapeutic potential of peony flower extract (PFE) in the tape-stripping-induced mouse model with skin barrier damage. Skin surface imaging, hydration measurements, H&E, proteomics, qPCR, and immunofluorescence were applied to clarify the potential mechanism of PFE in attenuating skin barrier impairment. <b>Results:</b> PFE significantly reduced erythema, TEWL, and edema while restoring epidermal architecture. Proteomics analysis identified cornified envelope formation and tight junction assembly as essential mechanisms in skin barrier repair. It increased the expression of key skin barrier proteins, including filaggrin (Flg), involucrin (Ivl), loricrin (Lor), claudin-1 (Cldn1), tight junction protein 1 (Tjp1), and occludin (Ocln). <b>Conclusions:</b> This study demonstrates that PFE restores skin barrier integrity by upregulating key structural proteins within the cornified envelope and tight junction. These findings suggest that PFE is a promising therapeutic candidate for skin barrier repair, with high potential in translational medicine applications.