Photoprotection exerted by sunscreens in a human cell line after UV damage

By Viviani, B. - Marinovich, M. - Galli, C.L.

In recent years, attention has been devoted to the biological effects of solar radiation. Exaggerated exposure to sunlight has underlined the importance of evaluating the ability of different products to protect skin from all the adverse effects of sunlight. In preliminary experiments, we used human keratinocytes in vitro to study the possible influence of sun irradiation on different biological events, in order to identify specific markers of photodamage. Unscheduled DNA synthesis was clearly observed in all the samples exposed to irradiation, in a dose-dependent manner. The best response was obtained when the UVA/UVB irradiation dose reached 44/7.2mJ/cm2 respectively. Under these conditions, the ability of the different sunscreens, mainly benzophenones, to protect from UV damage was assessed. The results seem to confirm the ability of such an in vitro model to evaluate the photoprotective action of the tested sunscreens.