Induction and excretion of ultraviolet-induced 8-oxo-2'-deoxyguanosine and thymine dimers in vivo: implications for PUVA

J Invest Dermatol. 2001 Feb;116(2):281-5. doi: 10.1046/j.1523-1747.2001.01251.x.

Abstract

Molecular epidemiology has linked ultraviolet-induced DNA damage with mutagenesis and skin carcinogenesis. Ultraviolet radiation may damage DNA in one of two ways: either directly, leading to lesions such as cyclobutane thymine dimers (T<>T), or indirectly, via photosensitizers that generate free radical species that may ultimately produce such oxidative lesions as 8-oxo-2'-deoxyguanosine. We report the results of a pilot, case control study in which seven, healthy, human volunteers (skin type II; aged 23-56 y; three male, four female) received a suberythemal dose of whole body irradiation from ultraviolet-A-emitting fluorescent tubes used in psoralen plus ultraviolet A therapy. First void, mid-stream urine samples were collected pre-exposure and daily postexposure, for up to 13 d. Analysis of urinary 8-oxo-2'-deoxyguanosine and cyclobutane thymine dimers was by competitive enzyme-linked immunosorbent assay (interassay coefficient of variation < or = 10%) and compared with a matched, control group of unirradiated individuals. A maximal increase in levels of urinary 8-oxo-2'-deoxyguanosine was seen 4 d post-ultraviolet exposure. A subsequent reduction was noted, before finally returning to baseline. Similarly, cyclobutane thymine dimer levels peaked 3 d postexposure, before returning to baseline. In contrast to the 8-oxo-2'-deoxyguanosine analysis, however, a second peak was noted at days 9-11, before again returning to baseline. This is the first report examining urinary 8-oxo-2'-deoxyguanosine and cyclobutane thymine dimers following ultraviolet exposure of healthy human subjects. This work illustrates the induction and time course for excretion of ultraviolet-induced lesions, perhaps alluding to repair and ultimately offering the potential to define psoralen plus ultraviolet A dosage regimes in terms of minimizing DNA damage and hence cancer risk.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 8-Hydroxy-2'-Deoxyguanosine
  • Adult
  • Case-Control Studies
  • DNA Damage / radiation effects
  • Deoxyguanosine / analogs & derivatives*
  • Deoxyguanosine / metabolism*
  • Deoxyguanosine / urine
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Humans
  • Male
  • Middle Aged
  • PUVA Therapy
  • Pilot Projects
  • Psoriasis / etiology
  • Pyrimidine Dimers / metabolism*
  • Reproducibility of Results
  • Skin Neoplasms / etiology
  • Ultraviolet Rays

Substances

  • Pyrimidine Dimers
  • 8-Hydroxy-2'-Deoxyguanosine
  • Deoxyguanosine