Skin photodamage a special damage in skin, is associated with UV-induced overproduction of reactive oxygen species (ROS) and the inactivation of NF-E2-related factor 2 (Nrf2). Skin-derived precursor cells (SKPs), a population of dermal stem cells, are considered to be involved in wound repair and skin regeneration through the activation of Nrf2. However, no reports concentrate on the treatment of skin photodamage with SKPs. To investigate the photoprotective role of SKPs in UV-induced photodamaged mice, 50 Balb/c hairless mice were divided into five groups (n = 10): normal group, model group, prevention group, treatment group, and control group. The latter four groups were dorsally exposed to a two-week UVA+UVB irradiation, whereas no any intervention was carried out in normal group. Mice in the prevention group received weekly SKP injections for two weeks the day before irradiation. Mice in the treatment and Hanks groups respectively received a two-time injection of SKPs and Hanks after irradiation. One week after final intervention, skin appearance, pathological characteristics, and oxidative indicators were evaluated by ELISA, immunohistochemical analysis, and western blotting. After irradiation, lesions appeared as erythema, edema, scales and wrinkles on mice dorsal skin; however, these were significantly ameliorated by subcutaneous SKP injection. Hyperkeratosis, acanthosis, and spongiosis in the epidermis, as well as dermal papillae edema and inflammatory cell infiltration, were observed in both model and control groups; however, these conditions resolved with SKPs. In addition, SKPs increased Nrf2, HO-1, GPX, SOD, CAT and GSH expression, while decreasing levels of ROS, MDA, and H2O2. Together with these findings, it is suggested that SKPs have a photoprotective role against UV-induced damage in mice, which may be associated with their ability to scavenge photo-oxidative insults and activate Nrf2.

Photoprotective effect of Skin-derived Precursors on skin photodamage in Balb/c hairless mice