Abstract
Collagen peptides (CPs) have demonstrated to exert beneficial effects on skin photoaging. However, little has been done to evaluate their effects on chronologically aged skin. Here, the effects of CPs from bovine bone on skin aging were investigated in chronologically aged mice. 13-month-old female Kunming mice were administered with CPs from bovine bone (200, 400 and 800 mg/kg body weight/day) or proline (400 mg/kg body weight/day) for 8 weeks. Mice body weight, spleen index (SI) and thymus index (TI), degree of skin laxity (DSL), skin components, skin histology and antioxidant indicators were analyzed. Ingestion of CPs or proline had no effect on mice skin moisture and hyaluronic acid content, but it significantly improved the skin laxity, repaired collagen fibers, increased collagen content and normalized the ratio of type I to type III collagen in chronologically aged skin. CPs prepared by Alcalase performed better than CPs prepared by collagenase. Furthermore, CPs intake also significantly improved the antioxidative enzyme activities in skin. These results indicate that oral administration of CPs from bovine bone or proline can improve the laxity of chronologically aged skin by changing skin collagen quantitatively and qualitatively, and highlight their potential application as functional foods to combat skin aging in chronologically aged process.