Abstract: The repair effects of collagen peptide (CP) on photoaged skin were introduced from three aspects: in vivo animal trials, in vivo clinical trials and in vitro cell trials. The effects of CP on extracellular matrix components and antioxidant indexes of mice dorsal skin under ultraviolet (UV) irradiation were analyzed from in vivo animal trials and the effects of CP on repairing photoaged skin by inhibiting the decrease of collagen and hyaluronic acid contents in mouse skin under UV irradiation were summarized. It was discussed that CP could promote collagen synthesis and inhibit collagen degradation respectively by inhibiting the abnormal changes of antioxidant indexes, the mechanism of CP repairing photoaged mouse skin was elucidated. The effects of oral CP on female skin hydration and collagen content were analyzed from in vivo clinical trials, and it was concluded that the effects of CP on repairing photoaged skin were through inhibiting the decrease of hydration and collagen content in the skin of female under UV irradiation. It was concluded that skin photoaging was closely related to the activation of mitogen-activated protein kinases (MAPK) signaling pathway and the inhibition of transforming growth factor-β (TGF-β) signaling pathway from in vitro cell trials and signaling pathway levels, and that CP could also dose-dependently promote the proliferation, migration and adhesion of skin fibroblasts under UV irradiation, thus increasing cell viability and accelerating wound healing. It was also discussed that the mechanism of CP repairing photoaged skin fibroblastswas through inhibiting the activation of MAPK signaling pathway and the weakening of TGF-β signaling pathway in skin fibroblasts under UV irradiation.

Key words: photoaged skin, collagen peptides, in vivo animal trials, in vivo clinical trials, in vitro cell trials