Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
J Clin Biochem Nutr. 2011 Sep;49(2):121-4. doi: 10.3164/jcbn.11-05. Epub 2011 May 25.
Aging and exposure to sunlight are two major factors in the deterioration of skin function. In this study, thirty-six fixed human skin samples from sun-exposed and unexposed areas from young and old individuals were used to evaluate the localization of oxidative stress according to levels and distribution of 8-hydroxy-2'-deoxyguanosine and N(ε)-(carboxymethyl)lysine in samples using immunohistochemistry. In the epidermis of the young, negligible amounts of 8-hydroxy-2'-deoxyguanosine and N(ε)-(carboxymethyl)lysine were detected in unexposed areas, whereas nuclear 8-hydroxy-2'-deoxyguanosine and cytoplasmic N(ε)-(carboxymethyl)lysine were increased in the lower epidermis in sun-exposed areas. In contrast, the aged presented prominent nuclear 8-hydroxy-2'-deoxyguanosine and nuclear N(ε)-(carboxymethyl)lysine in the epidermis of unexposed areas, concomitant with dermal increase in N(ε)-(carboxymethyl)lysine. However, the immunostaining of 8-hydroxy-2'-deoxyguanosine and N(ε)-(carboxymethyl)lysine revealed a decrease in the epidermis of sun-exposed areas in the aged. These results suggest an age-dependent difference in the adaptation and protective mechanisms of the epidermis against sunlight-associated oxidative stress, thus necessitating distinct standards for evaluation in each age group. Further investigation is warranted to elucidate underlying molecular mechanisms.
衰老是皮肤功能恶化的两个主要因素，暴露于阳光也是如此。本研究使用 36 份来自年轻人和老年人的固定人体皮肤样本（来自阳光照射和未照射的区域），通过免疫组织化学评估根据 8-羟基-2'-脱氧鸟苷和 N(ε)-(羧甲基)赖氨酸的水平和分布在样本中氧化应激的定位。在年轻人的表皮中，未暴露区域几乎检测不到 8-羟基-2'-脱氧鸟苷和 N(ε)-(羧甲基)赖氨酸，而在暴露于阳光的区域的下表皮中，核 8-羟基-2'-脱氧鸟苷和细胞质 N(ε)-(羧甲基)赖氨酸增加。相比之下，老年人在未暴露区域的表皮中呈现明显的核 8-羟基-2'-脱氧鸟苷和核 N(ε)-(羧甲基)赖氨酸，同时真皮中 N(ε)-(羧甲基)赖氨酸增加。然而，8-羟基-2'-脱氧鸟苷和 N(ε)-(羧甲基)赖氨酸的免疫染色显示，老年人暴露于阳光的区域表皮中的含量减少。这些结果表明，表皮对与阳光相关的氧化应激的适应和保护机制存在年龄依赖性差异，因此需要为每个年龄组制定不同的评估标准。需要进一步研究以阐明潜在的分子机制。
