Spectral Properties of Topical Retinoids Prevent DNA Damage and Apoptosis After Acute UV‐B Exposure in Hairless Mice¶

Abstract We showed in a recent study that topical retinyl palmitate prevented UV-B–induced DNA damage and erythema in humans. Given that retinyl palmitate is a precursor of retinoic acid, the biological form of vitamin A that acts through nuclear receptors, we wondered whether these protective effects toward UV-B exposure were either receptor dependent or linked to other properties of the retinoid molecule such as its spectral properties. We determined the epidermal retinoid profile induced by topical retinoic acid in hairless mice and analyzed its effect on markers of DNA photodamage (thymine dimers) and apoptosis following acute UV-B exposure; we compared these effects to those induced by other natural topical retinoids (retinaldehyde, retinol and retinyl palmitate) which do not directly activate the retinoid receptors. We then analyzed the direct action of these retinoids on UV-B–induced DNA damage and apoptosis in cultured A431 keratinocytes. Topical retinoic acid significantly decreased (≈50%) the nu...