Accumulation of oxidative DNA damage, 8-oxo-2 '-deoxyguanosine, and changeof repair systems during in vitro cellular aging of cultured human skin fibroblasts

Effects of in vitro cellular aging on the content of 8-oxo-2'-deoxyguanosin e, a typical oxidation product of DNA bases, were examined in cultured huma n skin fibroblasts. The 8-oxo-2'-deoxyguanosine content in the DNA of TIG-3 S cells established from skin tissues of a fetal donor increased immediatel y before the cessation of proliferation. TIG-114 and TIG-104 cells establis hed from skin tissues of adult and aged donors, respectively, showed simila r changes in 8-oxo-2'-deoxyguanosine content during in vitro cellular aging . The accumulation of 8-oxo-2'-deoxyguanosine in late-passage cells was dep endent on the number of cell divisions, and not on the cultivation time. In creases in the activities of superoxide dismutase and glutathione peroxidas e were observed prior to the increase in 8-oxo-2'-deoxyguanosine content, w hile the catalase activity decreased gradually during in vitro cellular agi ng at late-passage. Furthermore, the activities of 8-oxo-2-deoxyguanosine e ndonuclease and DNA polymerases decreased with the progression of prolifera tion. These results indicate that defense systems against oxidative stress in late-passage cells remain sufficiently active before the cessation of ce ll division, but that repair systems against oxidative damage decay at late -passage. Oxidative stress beyond the antioxidant capacity and/or repair ac tivity seems to result in an accumulation of 8-oxo-2'-deoxyguanosine in lat e-passage cells. (C) 2001 Elsevier Science B.V. All rights reserved.