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Title: The effect of selenium on ultraviolet-B radiation-induced damage to the skin
Author: Rafferty, Teresa S.
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 2000
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Selenium (Se) is a trace element found in many food sources, it is incorporated into specific selenoproteins. These include glutathione peroxidase and thioredoxin reductase which have strong antioxidant functions. In mice Se supplementation can reduce the number of skin tumours formed after UV irradiation. The purpose of the present thesis research was to characterise these protective mechanisms. To assess the effect of Se supplementation on UV irradiation of the skin, human skin cells were grown in vitro and supplemented with Se. Selenoprotein profiles were characterised by 75Se labelling. It was shown that primary human fibroblasts, melanocytes and keratinocytes all express unique patterns of selenoproteins. Se reduced the amount of cell death induced by ultraviolet- B radiation(UVB), it also reduced apoptotic cell death. Following keratinocytes Se reduced the induction of mRNA for IL-8, IL-6 and TNFa, but not the protein. In mouse keratinocytes the levels of mRNA for TNFa and IL-10 were reduced and IL-10 protein level was reduced. The effect of Se on the UV induction of DNA damage was assessed by the comet assay. The formation and rate of repair of cyclobutane dimer sites was not affected by Se. However the formation of oxidative damage was reduced. P53 protein is also induced following UVB irradiation, Se did not affect the abundance of the protein, but it did reduce the activity of P53 as measured by reporter assay. Se also reduced the production of lipid peroxides in keratinocytes following UVB. Mouse studies were also carried out where mice were fed different levels of Se for six weeks, then exposed to MED UVB. It was found that the number of Langerhan cells was higher in the Se replete animals and remained higher even after UVB treatment.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available