Berneburg M, Gattermann N, Stege H, Grewe M, Vogelsang K, Ruzicka T, Krutmann J
Department of Dermatology, Heinrich-Heine University, Düsseldorf, Germany.
Photochem Photobiol. 1997 Aug;66(2):271-5. doi: 10.1111/j.1751-1097.1997.tb08654.x.
Normal ageing processes are associated with an accumulation of mutations within the mitochondrial (mt) DNA. The most frequent mutation is a 4977 base pair (bp) deletion known as common deletion. In order to test the hypothesis that chronically sun-exposed skin is characterized by an increased mutation frequency of mtDNA, the mutation frequency of the common deletion between skin and another replicating tissue (the hematopoietic system) and chronically sun-exposed versus sun-protected skin was compared in the same individuals. This was done by comparing the amount of mutated mtDNA molecules with the whole mitochondrial genome in the same specimen with a semiquantitative polymerase chain reaction method, thus allowing direct comparison of different tissues. In all skin specimens the common deletion could be observed. In contrast only 3 of 10 blood samples revealed detectable amounts of the common deletion. Comparison of sun-exposed versus sun-protected skin exhibited a higher content of the common deletion in sun-exposed skin in 7 of 10 individuals. Additionally, a hitherto undescribed mtDNA mutation was detected exclusively in human skin. These studies indicate that exposure of human skin to solar radiation leads to an accumulation of mtDNA mutations, possibly via oxidative damage, which may play an important role in photoageing.
正常衰老过程与线粒体（mt）DNA内突变的积累有关。最常见的突变是一种4977个碱基对（bp）的缺失，称为常见缺失。为了验证长期暴露于阳光下的皮肤具有mtDNA突变频率增加这一假说，在同一受试者中比较了皮肤与另一个复制组织（造血系统）之间以及长期暴露于阳光下的皮肤与防晒皮肤之间常见缺失的突变频率。这是通过使用半定量聚合酶链反应方法比较同一样本中突变的mtDNA分子与整个线粒体基因组的量来实现的，从而能够直接比较不同组织。在所有皮肤样本中均能观察到常见缺失。相比之下，10份血液样本中只有3份显示出可检测到的常见缺失量。在10名个体中，有7名个体长期暴露于阳光下的皮肤与防晒皮肤相比，前者的常见缺失含量更高。此外，还在人类皮肤中专门检测到一种此前未描述的mtDNA突变。这些研究表明，人类皮肤暴露于太阳辐射会导致mtDNA突变的积累，可能是通过氧化损伤，这可能在光老化中起重要作用。
