Lopez-Torres M, Shindo Y, Packer L
Department of Molecular and Cell Biology, University of California, Berkeley 94720.
J Invest Dermatol. 1994 Apr;102(4):476-80. doi: 10.1111/1523-1747.ep12373032.
This is the first study of antioxidants and oxidative-damage-related parameters in epidermis and dermis of the skin as a function of age. The four major antioxidant enzymes (catalase, superoxide dismutase, glutathione reductase, and glutathione peroxidase), hydrophilic and lipophilic antioxidants, and lipid hydroperoxides were assayed in both epidermis and dermis of young and old hairless mice. Catalase, superoxide dismutase, and glutathione reductase had similar activity levels in young and old animals. Only glutathione peroxidase from epidermis showed an activity decrease due to age. This decrease became apparent when enzyme activity was expressed per mg of total cellular protein. Hydrophilic and lipophilic antioxidants did not change as a function of age, nor did lipid hydroperoxide levels. Both the absolute level of oxidized glutathione and the ratio of oxidized to reduced glutathione were higher in dermis from old mice. These results suggest that skin aging is not accelerated in old age due to a general decrease in the antioxidant capacity of the tissue. The data are compatible, however, with the idea that continuous damage to skin tissue by free radicals occurs throughout an organism's lifetime because scavenging cannot be 100% efficient.
这是第一项关于皮肤表皮和真皮中抗氧化剂及氧化损伤相关参数随年龄变化的研究。在年轻和年老的无毛小鼠的表皮和真皮中，对四种主要抗氧化酶（过氧化氢酶、超氧化物歧化酶、谷胱甘肽还原酶和谷胱甘肽过氧化物酶）、亲水性和脂溶性抗氧化剂以及脂质氢过氧化物进行了检测。过氧化氢酶、超氧化物歧化酶和谷胱甘肽还原酶在年轻和年老动物中的活性水平相似。仅表皮中的谷胱甘肽过氧化物酶活性随年龄降低。当以每毫克总细胞蛋白表示酶活性时，这种降低变得明显。亲水性和脂溶性抗氧化剂以及脂质氢过氧化物水平均不随年龄变化。老年小鼠真皮中氧化型谷胱甘肽的绝对水平以及氧化型与还原型谷胱甘肽的比率均较高。这些结果表明，老年时皮肤衰老不会因组织抗氧化能力普遍下降而加速。然而，这些数据与以下观点相符，即由于清除自由基的效率无法达到100%，在生物体的整个生命周期中，皮肤组织会持续受到自由基的损伤。
