The effect of anti-aging agents in skin oxidative stress induced by UV Radiation in vivo

UV radiation is related to oxidative stress and skin aging. UV induced reactive oxygen species lead to progressive degradation of dermal collagen and elastin. Four of the most known anti-aging agents were examined in the photoaged skin of hairless SKH-hr2 mice. 50 mice were irradiated with increasing UVR doses (0.5–2 MED) 3 times per week for 4 weeks. After the end of the irradiations, 5 formulations containing retinoic acid 0.05%, lactic acid 10%, salicylic acid 3%, epidermal growth factor 3.3% and the vehicle were applied on the back of the mice for 3 weeks. Hydration, transepidermal water loss (TEWL), elasticity and skin thickness, were frequently measured. After the end of applications, oxidative stress was evaluated in skin biopsies and strippings of stratum corneum using fluorescence spectroscopy, as well endogenous antioxidants using HPLC–EC detection. Epidermal thickening was evident in all mice after UV exposure. After treatment with lactic acid the thickness decreased significantly. Highest TEWL was observed in the retinoic acid group. The skin treated with salicylic acid demonstrated the lowest levels of ascorbic and uric acid. In strippings, lactic acid icreased the levels of antioxidants. Highest elasticity was measured in the retinoic acid group. In conclusion, retinoic and lactic acids seem to be the most effective treatments for the photodamaged skin.