Intensity-dependent direct solar radiation- and UVA-induced radical damage to human skin and DNA, lipids and proteins
Article
Haywood, R., Andrady, C., Kassouf, N. and Sheppard, N. 2011. Intensity-dependent direct solar radiation- and UVA-induced radical damage to human skin and DNA, lipids and proteins. Photochemistry and Photobiology. 87 (1), pp. 117-130. https://doi.org/10.1111/j.1751-1097.2010.00850.x
Type | Article |
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Title | Intensity-dependent direct solar radiation- and UVA-induced radical damage to human skin and DNA, lipids and proteins |
Authors | Haywood, R., Andrady, C., Kassouf, N. and Sheppard, N. |
Abstract | Skin can be exposed to high-intensity UV-radiation in hot countries and during sunbed use; however, the free-radical damage at these intensities is unknown. We used electron spin resonance spectroscopy to measure free-radical generation in ex vivo human skin/substitutes +/- the spin-trap 5,5 dimethyl-1-pyrroline N-oxide (DMPO) exposed to solar-irradiation equivalent to Mediterranean sunlight. Skin-substitutes, model DNA-photosensitizer systems, lipids and proteins were also irradiated with low-intensity UVA/visible light. Without DMPO a broad singlet was detected (using both irradiations) in skin/substitutes, nail-keratin, tendon-collagen, phospholipid and DNA+melanin or riboflavin. In addition to lipid-derived (tentatively tert-alkoxyl/acyl-) and protein radicals detected with DMPO at lower intensities, isotropic carbon-, additional oxygen- and hydrogen-adducts were detected in solar-irradiated skin/substitutes at higher intensities. Carbon-adducts were detected in UVA-irradiated human skin cells, DNA+melanin or riboflavin and soybean-phospholipid. Anisotropic protein-adducts, comparable to adducts in solar-irradiated tendon-collagen, were absent in UVA-irradiated skin fibroblasts suggesting the trapping of extracellular collagen radicals. Absence of hydrogen-adducts in fibroblasts implies formation in the extracellular compartment. We conclude damage at high intensities is part cellular (carbon- and oxygen-radicals) and part extracellular (protein- and hydrogen/H(+)+e(-) ), and skin substitutes are suitable for sunscreen testing. While UVA absorption and lipid-oxidation is direct, DNA and protein-oxidation require photosensitisation. |
Research Group | Biomarkers for Cancer group |
Molecular Biology group | |
Journal | Photochemistry and Photobiology |
ISSN | 0031-8655 |
Publication dates | |
Jan 2011 | |
Publication process dates | |
Deposited | 11 Apr 2016 |
Accepted | 18 Oct 2010 |
Output status | Published |
Copyright Statement | Access to full text restricted pending copyright check |
Additional information | First published: 8 December 2010 |
Digital Object Identifier (DOI) | https://doi.org/10.1111/j.1751-1097.2010.00850.x |
Language | English |
https://repository.mdx.ac.uk/item/86354
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