PROTECTION BY ZINC AGAINST UVA-INDUCED AND UVB-INDUCED CELLULAR AND GENOMIC DAMAGE IN-VIVO AND IN-VITRO

For many years, zinc salts have been used both topically and orally to treat minor burns and abrasions as well as to enhance wound repair in man and animals. In this study we describe the protective effects of zinc against UV-induced genotoxicity in vitro and against sunburn cell formation in mouse skin in vivo. Cultured skin cells from neonatal mi ce showed a dramatic increase in the number of micronuclei as a result of UVA and UVB irradiation. Inclusion of zinc at 5 mu g/mL in the med ium significantly reduced the frequency of micronuclei and of micronuc leated cells. In hairless mice, topical application of zinc chloride f or 5 consecutive days or a single application 2 h prior to UV exposure reduced the number of sunburn cells in the epidermis as did applicati on of zinc 1 h after exposure. Application 2 h after irradiation also tended to have a protective effect, although there was a large variati on between animals. It is proposed that an influx of zinc can protect epidermal cells against some of the more delayed effects of UV-induced damage.