Abstract
Chronically, sun-exposed human skin is characterized by dermal connective tissue damage with the accumulation of abnormal elastic fibers. However, little is known about the relationship between accumulation of abnormal elastic fibers and photodamaged skin. In the present study, we investigated the involvement of reactive oxygen species (ROS) in photoaged skin including abnormal accumulation of tropoelastin (TE) induced by ultraviolet A (UVA)-irradiation using an in vitro model of elastic fiber formation. Our data showed that the morphological appearances of TE deposition was observed following the addition of recombinant TE immediately after treatment with UVA-irradiation by immunofluorescence staining and semi-quantitative assay. Our data also revealed that treatment with hypoxanthine-xanthine oxidase, which generates superoxide radicals, stimulated TE deposition. Furthermore, we confirmed that abnormal TE deposition induced by UVA-irradiation was inhibited by treatment with Cu/Zn superoxide dismutase, a superoxide radical scavenger. Therefore, the data obtained suggest that superoxide radical is a candidate for inducing morphological changes and increasing TE deposition induced by UVA-irradiation in human skin fibroblast cells. The present study would be helpful for developing a prophylactic agent for photoaged skin.
