Abstract
The excessive loss of collagen is well known in photoaging skin. Collagen is synthesized by dermal fibroblasts and enzymatically digested by collagenase. Therefore, the quantitative alteration of collagen depends on the balance of synthesis and digestion. Skin is always exposed to oxygen stress and is suggested to be frequently generated the reactive oxygen species (ROS). We investigated the effect of ROS induced by xanthine-xanthine oxidase system on collagen production and collagenase activity in cultured human dermal fibroblasts. Collagen synthesis which was assessed by measuring 3H-proline incorporation into extracellular collagen, was decreased by ROS exposure. Collagenase activity was measured by using DNP-peptide as a synthetic substrate of collagen and increased by ROS exposure. These changes supported the biological alteration of collagen observed in photoaging skin. Extracts of Chouji and Gennosyouko which have superoxide-scavenging activity, prevented the ROS-induced changes significantly. These results suggest that ROS may be one of the factors which cause the decrease of collagen observed in photoaging skin.
