Abstract
The protective role of metallothionein in the skin against cellular damage by UVB was reviewed. Metallothionein is a cysteine rich protein with antioxidant and metal binding activities, which is readily inducible by exposure to cadmium. The protective effects of cadmium treatment on sunburn cell induction in mouse skin in vivo and human cell survival in vitro after UVB exposure have been investigated. The number of sunburn cells in mouse ear skin is significantly reduced in cadmium-treated mice. Bladder cancer cells exposed to cadmium also increase tolerance to UVB injury, implying a photoprotective role of metallothionein with scavenging activity by rich-SH residues. These results indicate that metallothionein may be an endogenous sunscreen with characteristic properties of non-toxicity and wide protection. Additional studies of non-toxic metallothionein-inducers are necessary, however, before undertaking clinical application.
