Anti-wrinkling effects of "L-Skin Care" and molecular mechanisms on hairless mouse skin caused by chronic ultraviolet B irradiation.

Background: Naturally occurring antioxidants were used to regulate the skin damage caused by ultraviolet (UV) radiation because several antioxidants have demonstrated that they can inhibit wrinkle formation through prevention of matrix metalloproteinases (MMPs) and/or increase of collagen synthesis. We examined the effect of oral administration of the antioxidant mixture ("L-Skin Care") on UVB-induced wrinkle formation. In addition, we investigated the possible molecular mechanisms of photoprotection against UVB through inhibition of collagen-degrading MMP activity or through enhancing of pro collagen synthesis in mouse dorsal skin. Methods: Female SKH-l hairless mice were orally administrated "L-Skin Care" (test group) or vehicle (control group) for 10 weeks with UVB irradiation by three times a week. The intensity of irradiation was gradually increased from 30 to $180mJ/cm^2$. Microtopographic and histological assessments of the dorsal skins were carried out at the end of 10 weeks to evaluate wrinkle formation. Western blot analysis and EMSA were also carried out to investigate the changes in the balance of collagen synthesis and collagen degradation. Results: Our "L-Skin Care" significantly reduced UVB-induced wrinkle formation, accompanied by significant reduction of epidermal thickness, and UVB-induced hyperplasia, acanthosis and hyperkeratosis. Oral administration of "L-Skin Care" significantly prevented UVB-induced expressions of MMPs, mitogen-activated protein (MAP) kinases and activation of activator protein (AP)-1 transcriptional factor in addition to enhanced type I procollagen and transforming growth factor-$\beta$ (TGF-$\beta$) expression. Conclusion: Oral administration of "L-Skin Care" significantly inhibited wrinkle formation caused by chronic UVB irradiation through significant inhibition of UVB-induced MMP activity accompanied with enhancement of collagen synthesis.