lular uptake was necessary for the protective effect.
UVR generates reactive oxygen species in skin
(UVA UVB), resulting in oxidation of proteins.50
DNA repair enzymes appear to be especially prone
to UVA damage,51 which may lead to inefficient
excision of pyrimidine dimers. Topical antioxidants
may help to prevent this damage. Chen et al52 demonstrated,
in UV-irradiated mice, a 55% reduction of
pyrimidine dimer formation in epidermal p53 by
topical -tocopherol. However, they saw little
change in effect from 1 to 10 hours after irradiation
and reasoned that it was unlikely that the effect
related to repair.52 Although we cannot completely
eliminate a sunscreen effect to explain our data with
vitamins C and E, we believe that the effect is minimal.
In support, protection against photocarcinogenesis
and pyrimidine dimer formation has been
reported using other antioxidants including green
tea polyphenols53,54 and silymarin55 in the apparent
absence of UVR absorption.