Abstract: By establishing a UVB-induced mouse skin photodamage model, the photodamage repairing effect of peony seed oil emulsion (PSOE) was systematically evaluated. In this paper, the Franz diffusion cell method was used to compare the skin penetration and retention properties of PSOE and pure peony seed oil (PSO). The antioxidant capacity was evaluated by measuring the intracellular reactive oxygen species (ROS) level. An animal model was established to observe skin healing, erythema degree, and elasticity changes, and histopathological analysis (HE and Masson staining) and molecular detection (ELISA and immunohistochemistry to detect the expression of TNF-α, IL-1β, IL-6, and MMP-1) were carried out. The experimental results showed that the cumulative skin penetration amount of PSOE was approximately 1.5 times higher than that of PSO, and the skin retention rate increased by about 4 times. Its ability to scavenge UVB-induced ROS was significantly better than that of the commercial emulsion (CE) and the blank emulsion base (EB). Animal experiments indicated that the wound healing rate of the PSOE treated group reached 92.31±3.53% on the 7th day. The infiltration of inflammatory cells in the dermis decreased, the epidermal thickness recovered to nearly the normal level, and the density of collagen fibers increased. Molecular detection results showed that PSOE down-regulated the expression of TNF-α, IL-1β, IL-6, and MMP-1. In conclusion, PSOE effectively repairs UVB-induced skin photodamage through multiple synergistic pathways, including enhancing transdermal delivery, inhibiting oxidative stress, reducing the inflammatory response, promoting collagen regeneration, and regulating matrix metabolism.

Key words: peony seed oil, emulsion, photodamage, collagen deposition, inflammatory response