Effects of oral administration of collagen peptides on skin collagen content and its underlying mechanism using a newly developed low collagen skin mice model

A low collagen skin mice model was established and used to evaluate the effects of orally administered collagen peptide (CP) and glycine, alanine, and proline mixture (GAP) on the collagen content in the skin of mice. This model was established by feeding mice a low protein diet for 8 weeks. The oral administration of 50 mg/kg of CP led to increased collagen content in the skin, although that effect was counteracted in a dose-dependent manner. The oral administration of GAP led to a dose-dependent increase in the collagen content of the mouse skin. Prolyl-hydroxyproline led to a dose-dependent increase in the proliferation of primary cultured murine fibroblasts, and proline caused an increase in fibroblast differentiation. The results of this study demonstrated that CP and GAP influenced the collagen content of mouse skin by changing the state of fibroblasts. (C) 2015 Elsevier Ltd. All rights reserved.