Shindo Y, Witt E, Han D, Epstein W, Packer L
Department of Molecular and Cell Biology, University of California, Berkeley 94720.
J Invest Dermatol. 1994 Jan;102(1):122-4. doi: 10.1111/1523-1747.ep12371744.
We measured enzymic and non-enzymic antioxidants in human epidermis and dermis from six healthy volunteers undergoing surgical procedures. Epidermis was separated from dermis by curettage and antioxidants were measured by high-performance liquid chromatography (HPLC) or standard spectrophotometric methods. The concentration of every antioxidant (referenced to skin wet weight) was higher in the epidermis than in the dermis. Among the enzymic antioxidants, the activities of superoxide dismutase, glutathione peroxidase, and glutathione reductase were higher in the epidermis compared to the dermis by 126, 61 and 215%, respectively. Catalase activity in particular was much higher (720%) in the epidermis. Glucose-6-phosphate dehydrogenase and isocitrate dehydrogenase, which provide reduced nicotinamide adenine dinucleotide phosphate (NADPH), also showed higher activity in the epidermis than the dermis by 111% and 313%, respectively. Among the lipophilic antioxidants, the concentration of alpha-tocopherol was higher in the epidermis than the dermis by 90%. The concentration of ubiquinol 10 was especially higher in the epidermis, by 900%. Among the hydrophilic antioxidants, concentrations of ascorbic acid and uric acid were also higher in the epidermis than in the dermis by 425 and 488%, respectively. Reduced glutathione and total glutathione were higher in the epidermis than in the dermis by 513 and 471%. Thus the antioxidant capacity of the human epidermis is far greater than that of dermis. As the epidermis composes the outermost 10% of the skin and acts as the initial barrier to oxidant assault, it is perhaps not surprising that it has higher levels of antioxidants.
我们对6名接受外科手术的健康志愿者的人体表皮和真皮中的酶促抗氧化剂和非酶促抗氧化剂进行了测量。通过刮除术将表皮与真皮分离，并采用高效液相色谱法（HPLC）或标准分光光度法测量抗氧化剂。每种抗氧化剂的浓度（以皮肤湿重为参照）在表皮中均高于真皮。在酶促抗氧化剂中，超氧化物歧化酶、谷胱甘肽过氧化物酶和谷胱甘肽还原酶的活性在表皮中分别比真皮中高126%、61%和215%。特别是过氧化氢酶活性在表皮中要高得多（720%）。提供还原型烟酰胺腺嘌呤二核苷酸磷酸（NADPH）的葡萄糖-6-磷酸脱氢酶和异柠檬酸脱氢酶在表皮中的活性也分别比真皮中高111%和313%。在亲脂性抗氧化剂中，α-生育酚的浓度在表皮中比真皮中高90%。泛醇10的浓度在表皮中尤其高，达900%。在亲水性抗氧化剂中，抗坏血酸和尿酸的浓度在表皮中也分别比真皮中高425%和488%。还原型谷胱甘肽和总谷胱甘肽在表皮中比真皮中高513%和471%。因此，人体表皮的抗氧化能力远大于真皮。由于表皮构成皮肤最外层的10%，并作为抵御氧化剂攻击的初始屏障，其具有较高水平的抗氧化剂或许并不令人惊讶。
