Protective and determining factors for the overall lipid peroxidation in ultraviolet A1-irradiated fibroblasts: in vitro and in vivo investigations.
BACKGROUND
Lipid peroxidation (LPO) is one major effector mechanism by which ultraviolet (UV) A contributes to photoageing and the promotion of skin cancer. It is a fingerprint of photo-oxidative stress within the skin, and is initiated by several pathways, with different reactive oxygen species (ROS) and iron ions being involved.


OBJECTIVE
To elucidate factors involved in UVA1-induced LPO in human dermal fibroblasts and mouse dermis, and the role of antioxidant enzymes in protecting cells against LPO.


METHODS
Using a highly sensitive high-performance liquid chromatography procedure, we measured malondialdehyde (MDA), a specific metabolic tracer molecule for LPO, to determine the overall LPO produced by a given UVA1 dose in vitro and in vivo. By using the iron chelator desferrioxamine (DFO), the hydroxyl radical scavenger dimethylsulphoxide (DMSO) and fibroblasts that specifically overexpress single antioxidant enzymes, we further indirectly assessed the protective effect of manganese superoxide dismutase (MnSOD), catalase and phospholipid hydroperoxide glutathione peroxidase (PHGPx) as well as the relative importance of different ROS and the role of transitional iron for the total amount of LPO induced by a distinct UVA dose.


RESULTS
UVA1 irradiation resulted in a time- and dose-dependent increase in MDA levels in vitro, and the in vitro results were shown to have in vivo relevance. Fibroblasts incubated with DFO or DMSO produced lower levels of MDA than controls, as did fibroblasts overexpressing MnSOD, catalase or PHGPx.


CONCLUSIONS
The cellular iron pool and hydroxyl radicals were the most important determining factors for the total amount of MDA produced after a given UVA1 dose, and PHGPx overexpression had the greatest protective effect against LPO.
Dissemond
J
J
Department of Dermatology, University of Essen, Hufelandstrasse 55, D-45122 Essen, Germany.
Schneider
L A
LA
Brenneisen
P
P
Briviba
K
K
Wenk
J
J
Wlaschek
M
M
Scharffetter-Kochanek
K
K
D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D002470:Cell Survival / Q000528:radiation effects; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D002851:Chromatography, High Pressure Liquid; D004307:Dose-Response Relationship, Radiation; D005347:Fibroblasts / Q000378:metabolism / Q000528:radiation effects*; D006801:Humans; D017665:Hydroxyl Radical / Q000378:metabolism; D007501:Iron / Q000502:physiology; D015227:Lipid Peroxidation / Q000528:radiation effects*; D008315:Malondialdehyde / Q000378:metabolism; D051379:Mice; D008812:Mice, Hairless; D012867:Skin / Q000166:cytology / Q000378:metabolism / Q000528:radiation effects*; D014162:Transfection; D014466:Ultraviolet Rays
D000975:Antioxidants; D017665:Hydroxyl Radical; D008315:Malondialdehyde; D007501:Iron