Action spectrum for UV-induced lipid peroxidation in cultured human skin fibroblasts (original) (raw)
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Journal of Investigative Dermatology, 1993
Cultured human skin fibroblasts from healthy donors were irradiated with 180 kJ' m-2 ultraviolet (UV) A (320-400 nm) and assayed for thiobarbituric acid-reactive substances (TBARS), taken as an indicator oflipid peroxidation. Antioxidant defenses, inCluding total glutathione (GSH) levels, superoxide dismutase (SOD), glutathione peroxidase (GSHPx), and catalase (Cat) activities were simultaneous ly assayed before and after irradiation. For the various donors, with different activities of these antioxidant systems before irradiation, TBARS correlated positively with SOD activity and negatively with Cat activity, whereas no correlation with E xposure of human skin to solar light may result in shortterm responses, such as erythema and pigmentation, and long-term responses, such as carcinogenesis and ag ing [1-5]. It has long been established that the ultraviolet (UV) component (290-400 nm) is by far the most effective in triggering these responses in human or model animals and in producing lethal and mutagenic damage in cultured cells. Action spectra for these responses exhibit very similar shapes and indicate that UVB (290-320 nm) is much more effective than UV A (320-400 nm) [1,6-9]. Cell killing, mutage nesis, and carcinogenesis are generally linked to DNA damage, and the efficiency of UVB is associated with direct absorption ofUVB photons by DNA, which leads to various DNA damage [9,10]. Although UVB is much more Manuscript
Journal of Photochemistry and Photobiology B: Biology, 2012
This study provides evidence that skin oxidative stress injury caused by UVB irradiation is mediated predominantly by reactive oxygen species immediately after irradiation and by reactive nitrogen species at later time points. Animals were pre-treated with free radical scavengers (deferrioxamine, histidine), a-tocopherol, or inhibitors of nitric oxide synthase (NOS) (L-NAME or aminoguanidine) or left untreated and subjected to UVB irradiation. a-Tocopherol inhibited the increase in lipid peroxidation, as evaluated by chemiluminescence at 0 h and 24 h after UVB irradiation. Immediately after UVB irradiation, lipid peroxidation increased moderately and was abolished by free radical scavengers but not by NOS inhibitors. Likewise, the reduction of antioxidant capacity was not reversed by NOS inhibitors. Nitric oxide augmentation was not observed at this time point. Twenty-four hours after irradiation, increased lipid peroxidation levels and nitric oxide elevation were observed and were prevented by NOS inhibitors. Low concentrations of GSH and reduced catalase activity were also observed. Altogether, these data indicate that reactive oxygen species (singlet oxygen and hydroxyl radicals) are the principal mediators of immediate damage and that reactive nitrogen species (Å NO and possibly ONOO À) seem to be involved later in skin oxidative injury induced by UVB radiation. The reduced catalase activity and low level of GSH suggest that Å NO and H 2 O 2 may react to generate ONOO À , a very strong lipid peroxidant species.
Free radical research, 2017
Short-term exposure to ultraviolet A (UVA) radiation can directly injure our skin through inflammatory response and indirectly through oxidative stress, triggering polyunsaturated fatty acid (PUFA) peroxidation in skin cell membrane and formation of DNA adduct, 8-hydroxy-2'-deoxyguanosine (8-OHdG). It is known that UVA exposure leads to photoaging, immunosuppression and skin cancer. However, the changes in PUFA and its oxidized metabolites, and cell cycle after short UVA exposure, are debatable. In this study, human keratinocytes (HaCaT) were exposed to low dose (5 J/cm(2)) and high dose (20 J/cm(2)) of UVA and assessed immediately, 8 h, 12 h, and 24 h post-treatment. Both doses showed a transient suppression in S-phase after 8 h of UVA exposure, and G2/M phase arrest after 12-h UVA exposure in the cell cycle but subsequently returned to normal cycle. Also, no observable DNA damage took place, where 8-OHdG levels were below par after 24-h UVA exposure. A dose of 20 J/cm(2) UVA s...
Oxidative medicine and cellular longevity, 2013
There are numerous studies concerning the effect of UVB light on skin cells but fewer on other skin components such as the interstitial fluid. This review highlights high-density lipoprotein (HDL) and low-density lipoprotein (LDL) as important targets of UVB in interstitial fluid. Tryptophan residues are the sole apolipoprotein residues absorbing solar UVB. The UVB-induced one-electron oxidation of Trp produces (•)Trp and (•)O2 (-) radicals which trigger lipid peroxidation. Immunoblots from buffered solutions or suction blister fluid reveal that propagation of photooxidative damage to other residues such as Tyr or disulfide bonds produces intra- and intermolecular bonds in apolipoproteins A-I, A-II, and B100. Partial repair of phenoxyl tyrosyl radicals (TyrO(•)) by α -tocopherol is observed with LDL and HDL on millisecond or second time scales, whereas limited repair of α -tocopherol by carotenoids occurs in only HDL. More effective repair of Tyr and α -tocopherol is observed with t...
Archives of Dermatological Research, 2008
Reactive oxygen species (ROS) play important roles in the process of ultraviolet-induced skin damage or photoaging. Although many enzymatic and chemical methods have been developed for evaluating ROS, evaluation methods for ROS generation in living systems are quite limited. Here we propose a unique system to visualize UVB-induced ROS and investigate the biological impact of ROS. In brief, a human skin equivalent model (HSEM) was exposed to UVB. Emitted luminescence from the HSEM was visualized and semi-quantiWed by using a chemiluminescent probe (CLA) and an ultra low-light imaging apparatus. The eVects of anti-oxidative compounds such as ascorbate, -carotene, superoxide dismutase (SOD), and yeast ferment Wltrate (YFF) on the HSEM were evaluated by semi-quantiWcation of emitted chemiluminescence (CL) intensities, MTT assay and 8-hydroxy-2Ј-deoxyguanosine (8-OHdG) staining. Visualization of time-and spacedependent dynamics of ROS generation in the HSEM was successfully achieved by utilizing a sensitive two-dimensional ultra-low light luminograph. Treatments with -carotene and SOD eVectively suppressed CL intensity, indicating the generation of 1 O 2 and O 2 ·¡ in the HSEM under UVB exposure. Tested anti-oxidative compounds also attenuated UVB-induced CL and ameliorated the induced skin damages in terms of 8-OHdG formation and cell death. As a conclusion, this model is useful for not only visualizing the production of UVB-induced ROS in real-time but also evaluating the eYcacy of topically applied anti-oxidative compounds to suppress ROS generation and attenuate sequential chemical and biological responses.
Archives of Dermatological Research, 2006
Adaptive cellular protection against UVA-1-induced lipid peroxidation in human dermal fibroblasts shows donor-to-donor variability and is glutathione dependent Abstract Photo-oxidative stress and subsequent lipid peroxidation (LPO) is one of the major mechanisms of UVA-related skin pathology. The skin's protection system against photo-oxidative stress involves low molecular scavengers as well as highly specialised antioxidant enzymes like glutathione peroxidase (GPX). Against repetitive UVA-1 exposures in vitro it is partly adaptive, as recent studies have shown exemplarily for antioxidant enzymes. We now investigated in vitro by repetitively irradiating human dermal fibroblasts with UVA-1 whether this adaptive response might reflect itself in reduced cellular membrane damage, that is, LPO. Our experiments show that the degree of cellular protection against LPO and the adaptive potential of the cells against a repetitive UVA-1 exposure varies from donor-to-donor and depends highly on glutathione.
Dermal contributions to UVA-induced oxidative stress in skin
Photodermatology, Photoimmunology & Photomedicine, 2009
Background: When the skin is exposed to solar irradiation, UVA photons interact with skin tissues and induce excessive reactive oxygen species, resulting in oxidative stress. We have shown in a previous study that in vivo chemiluminescence's measurement can be used to evaluate the overall level of UVA-induced oxidative stress in human skin. However, the origin of the observed chemiluminescence signals remains unclear. Methods: UVA-induced chemiluminescence measurements were conducted: (a) in vitro on collagen solutions and solid collagen sheet preparations, (b) ex vivo on human and mouse skin biopsies, and (c) in vivo on human skin of various constitutive pigmentation levels. Fluorescence was measured on collagen in vitro as well as on skin for the in vivo experiments. Results: We found in the in vitro experiments that UVA-induced chemiluminescence increases with the presence of collagen cross-links. When dermal sides were exposed to UVA irradiation, both mouse and human skin biopsies demonstrated significantly higher chemiluminescence levels than when epidermal sides were exposed to UVA. The amount of collagen cross-links decreases slightly following UVA exposure, as shown both by in vivo fluorescence and by UVA-induced chemiluminescence. Finally, there was less measurable UVA-induced chemiluminescence in dark skin compared with light pigmented skin in vivo. Conclusions: The dermis is very sensitive to UVA photons. Dermal cross-links are potential UVA sensitizers. The oxidative stress induced by UVA and measured by chemiluminescence may largely be attributed to the breakdown of dermal collagen cross-links.
International Journal of Mass Spectrometry, 2006
Proton-transfer reaction mass spectrometry (PTR-MS) was used to study ultraviolet (UV) light-induced lipid peroxidation in human skin, in vivo. Emissions of volatile organic compounds (VOCs) in the mass range between 20 and 150 amu in the headspace of the skin of 16 healthy volunteers were monitored before, during and after irradiation in an on-line and non-invasive fashion. From these experiments, five volatile substances were found to reflect the damage caused by UV-radiation. The two major compounds (monitored at mass 45 and 59 amu) were identified as acetaldehyde and propanal using a combination of Tenax-based gas chromatographic pre-separation with PTR-MS. The other volatiles (with characteristic ions at, among others, masses 73 and 87 amu) could not be identified. Simultaneous measurement of the established lipid peroxidation biomarker ethene using laser-based photoacoustic trace gas detection revealed a similar pattern and statistically significant correlations between VOC production measured with PTR-MS and ethene. Variations in UV-radiation intensity were reflected by the amount of acetaldehyde and propanal emitted from the skin. Our results show that acetaldehyde and propanal can be used as biomarkers for lipid peroxidation.
UVA-induced oxidative damage and cytotoxicity depend on the mode of exposure
Journal of Photochemistry and Photobiology B: Biology, 2005
The reciprocity rule (Bunsen-Roscoe law) states that a photochemical reaction is directly proportional to the total energy dose, irrespective of the dose distribution. In photomedicine the validity of this law is usually taken for granted, although the influence of radiation intensity and dose distribution are largely unknown. We have examined in a tissue culture model the effects of fractionated versus single dose exposure to UV from a metal halide source on survival, DNA synthesis, glutathione, and oxidative membrane damage. Exposure to fractionated UVA was followed by an increased rate of cell death compared to single dose exposure, when intervals between fractions where short (10-120 min). Longer intervals had the opposite effect. Corresponding results were obtained for DNA synthesis (BrdU incorporation). The increased cytotoxicity of dose fractionation with short intervals could not be abrogated by non-enzymatic antioxidants (astaxanthin, ascorbic acid, a-tocopherol). Fractionated irradiation with short intervals led to higher degree of depletion of glutathione (GSH) and to enhanced formation of thiobarbituric acid reactive substances (TBARS) in comparison to an identical single dose. Long intervals between fractions induced opposite effects. Taken together, these data indicate that immediately after UVA exposure cells are more sensitive to a further oxidative attack making repeated exposure with short intervals more cytotoxic than continuous single dose UVA. This might have implications also for responses to UVA in vivo and further studies will have to extend these findings to the situation in healthy and diseased human skin.