F. Bernerd et al., Evaluation of the protective effect of sunscreens on in vitro reconstructed human skin exposed to UVB or UVA irradiation, PHOTOCHEM P, 71(3), 2000, pp. 314-320
We have previously shown that skin reconstructed in vitro is a useful model
to study the effects of UVB and UVA exposure. Wavelength-specific biologic
al damage has been identified such as the formation of sunburn cells (SBC)
and pyrimidine dimers after UVB irradiation and alterations of dermal fibro
blasts after UVA exposure. These specific effects were selected to evaluate
the protection afforded by two sunscreens after topical application on the
skin surface. Simplified formulations having different absorption spectra
but similar sun protection factors were used, One contained a classical UVB
absorber, 2-ethylhexyl-p-methoxycinnamate. The other contained a broad-spe
ctrum absorber called Mexoryl(R) SX, characterized by its strong absorbing
potency in the UVA range, Both filters were used at 5% in a simple water/oi
l vehicle. The evaluation of photoprotection on in vitro reconstructed skin
revealed good efficiency for both preparations in preventing UVB-induced d
amage, as shown by SBC counting and pyrimidine dimer immunostaining, By con
trast, only the Mexoryl(R) SX-containing preparation was able to efficientl
y prevent UVA-specific damage such as dermal fibroblast disappearance. Our
data further support the fact that skin reconstructed irt vitro is a reliab
le system to evaluate the photoprotection provided by different sunscreens
against specific UVB and UVA biological damage.