Thiele J J, Traber M G, Tsang K, Cross C E, Packer L
Department of Molecular and Cell Biology, University of California, Berkeley 94720-3200, USA.
Free Radic Biol Med. 1997;23(3):385-91. doi: 10.1016/s0891-5849(96)00617-x.
To evaluate skin susceptibility to ozone (O3) and to localize possible oxidative damage within the skin layers, hairless mice were exposed to 10 ppm O3 or air (0 ppm O3) for 2 h. The mice were euthanized, the skin removed and frozen. Three skin layers (upper epidermis, lower epidermis/papillary dermis, and dermis) were separated, antioxidant concentrations (alpha-tocopherol and ascorbic acid) and the lipid peroxidation product malondialdehyde (MDA) measured. In the upper epidermis, O3 significantly depleted alpha-tocopherol (22%; p < .05) and ascorbic acid (55%; p < .01). These antioxidants were unchanged by O3 in the lower skin layers. More remarkably, MDA increased ten-fold in the upper epidermis (p < .001) and two-fold in the lower epidermis/papillary epidermis (p < .05); it was unchanged in the dermis. Thus, exposure to O3 in vivo depletes ascorbic acid and alpha-tocopherol and strongly induces lipid peroxidation in skin. High MDA concentrations measured in the upper epidermis suggest that O3 reacts directly with fatty acids on the skin surface layers. These results further suggest that chronic exposure to lower O3 concentrations found in urban smog could potentially have implications for skin health.
为了评估皮肤对臭氧（O3）的易感性，并确定皮肤各层中可能的氧化损伤位置，将无毛小鼠暴露于10 ppm的O3或空气（0 ppm O3）中2小时。对小鼠实施安乐死后，取下皮肤并冷冻。分离出三层皮肤（上表皮、下表皮/乳头真皮和真皮），测量抗氧化剂浓度（α-生育酚和抗坏血酸）以及脂质过氧化产物丙二醛（MDA）。在上表皮中，O3显著消耗了α-生育酚（22%；p < 0.05）和抗坏血酸（55%；p < 0.01）。在下层皮肤中，这些抗氧化剂未因O3而改变。更值得注意的是，MDA在上表皮中增加了10倍（p < 0.001），在下表皮/乳头表皮中增加了2倍（p < 0.05）；在真皮中则未发生变化。因此，体内暴露于O3会消耗抗坏血酸和α-生育酚，并强烈诱导皮肤中的脂质过氧化。在上表皮中测得的高MDA浓度表明，O3直接与皮肤表层的脂肪酸发生反应。这些结果进一步表明，长期暴露于城市烟雾中较低浓度的O3可能对皮肤健康产生影响。
