Godic Aleksandar, Poljšak Borut, Adamic Metka, Dahmane Raja
Department of Dermatology, Cambridge University Hospitals, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK.
Faculty of Health Studies, Zdravstvena pot 5, 1000 Ljubljana, Slovenia.
Oxid Med Cell Longev. 2014;2014:860479. doi: 10.1155/2014/860479. Epub 2014 Mar 26.
Skin cells are constantly exposed to reactive oxygen species (ROS) and oxidative stress from exogenous and endogenous sources. UV radiation is the most important environmental factor in the development of skin cancer and skin aging. The primary products caused by UV exposure are generally direct DNA oxidation or generation of free radicals which form and decompose extremely quickly but can produce effects that can last for hours, days, or even years. UV-induced generation of ROS in the skin develops oxidative stress when their formation exceeds the antioxidant defense ability. The reduction of oxidative stress can be achieved on two levels: by lowering exposure to UVR and/or by increasing levels of antioxidant defense in order to scavenge ROS. The only endogenous protection of our skin is melanin and enzymatic antioxidants. Melanin, the pigment deposited by melanocytes, is the first line of defense against DNA damage at the surface of the skin, but it cannot totally prevent skin damage. A second category of defense is repair processes, which remove the damaged biomolecules before they can accumulate and before their presence results in altered cell metabolism. Additional UV protection includes avoidance of sun exposure, usage of sunscreens, protective clothes, and antioxidant supplements.
皮肤细胞不断受到来自外源性和内源性来源的活性氧（ROS）和氧化应激的影响。紫外线辐射是皮肤癌和皮肤衰老发展过程中最重要的环境因素。紫外线照射产生的主要产物通常是直接的DNA氧化或自由基的产生，这些自由基形成和分解极快，但能产生持续数小时、数天甚至数年的影响。当紫外线诱导皮肤中ROS的生成超过抗氧化防御能力时，就会产生氧化应激。可以通过两个层面来降低氧化应激：减少紫外线辐射暴露和/或提高抗氧化防御水平以清除ROS。我们皮肤唯一的内源性保护是黑色素和酶促抗氧化剂。黑色素由黑素细胞沉积，是皮肤表面抵御DNA损伤的第一道防线，但它不能完全防止皮肤损伤。第二类防御是修复过程，即在受损生物分子积累之前以及它们的存在导致细胞代谢改变之前将其清除。额外的紫外线防护措施包括避免阳光照射、使用防晒霜、穿着防护服和补充抗氧化剂。
