Suppression of Light-Induced Oxidative Stress in the Retina by Mitochondria-Targeted Antioxidant (original) (raw)
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Neuroscience Letters, 2006
Exposure to excessive light induces retinal photoreceptor cell damage, which may involve lipid peroxidation. Morphological changes and the detection of internucleosomal DNA fragmentation confirmed the retinal damage caused by exposure of the retina of Balb/c mice to white fluorescent light (5000 lux, 2 h). The total amounts of hydroxyoctadecadienoic acid (tHODE) and 8-iso-prostaglandin F 2␣ (8-iso-PGF 2␣ ) in the retinas obtained from light-exposed mice were assessed after reduction and saponification. In this method, both the free and ester forms of hydroperoxides, hydroxides, and ketones of linoleic acid are measured as tHODE by gas chromatography-mass spectrometry (GC-MS) analysis. When compared with controls, a significant increase in the concentrations of tHODE and 8-iso-PGF 2␣ was observed 24 h after light exposure. Furthermore, the stereoisomeric ratio (Z,E)-HODE/(E,E)-HODE decreased after light exposure, suggesting the involvement of free-radical-mediated peroxidation. By the immunohistochemical technique, it was confirmed that 8-iso-PGF 2␣ increased in the inner plexiform layer (IPL), outer plexiform layer (OPL), rod outer segment, and choroidal layer, while 13-HODE increased in the OPL and rod inner segment after light exposure. These results demonstrate that tHODE and 8-iso-PGF 2␣ assessed by the present method are appropriate biomarkers responding to retinal photooxidative stress in vivo.
Cell death & disease, 2018
Blue light is an identified risk factor for age-related macular degeneration (AMD). We investigated oxidative stress markers and mitochondrial changes in A2E-loaded retinal pigment epithelium cells under the blue-green part of the solar spectrum that reaches the retina to better understand the mechanisms underlying light-elicited toxicity. Primary retinal pigment epithelium cells were loaded with a retinal photosensitizer, AE2, to mimic aging. Using a custom-made illumination device that delivers 10 nm-wide light bands, we demonstrated that A2E-loaded RPE cells generated high levels of both hydrogen peroxide (HO) and superoxide anion (O) when exposed to blue-violet light. In addition, they exhibited perinuclear clustering of mitochondria with a decrease of both their mitochondrial membrane potential and their respiratory activities. The increase of oxidative stress resulted in increased levels of the oxidized form of glutathione and decreased superoxide dismutase (SOD) and catalase ...
Photochemistry and Photobiology, 2007
Throughout the lifetime of an individual, light is focused onto the retina. The resulting photooxidative stress can cause acute or chronic retinal damage. The pathogenesis of age-related macular degeneration (AMD), the leading cause of legal blindness in the developed world, involves oxidative stress and death of the retinal pigment epithelium (RPE) followed by death of the overlying photoreceptors. Evidence suggests that damage due to exposure to light plays a role in AMD and other age-related eye diseases. In this work a system for lightinduced damage and death of the RPE, based on the human ARPE-19 cell line, was used. Induction of mitochondriaderived reactive oxygen species (ROS) is shown to play a critical role in the death of cells exposed to short-wavelength blue light (425 ± 20 nm). ROS and cell death are blocked either by inhibiting the mitochondrial electron transport chain or by mitochondria-specific antioxidants. These results show that mitochondria are an important source of toxic oxygen radicals in blue light-exposed RPE cells and may indicate new approaches for treating AMD using mitochondria-targeted antioxidants.
Oxidative stress and histological changes in a model of retinal phototoxicity in rabbits
Oxidative medicine and cellular longevity, 2014
Photochemical damage occurs after an exposure to high energy radiation within the visible spectrum of light, causing morphological changes in the retina and the formation of superoxide anion. In this study we created a model of phototoxicity in rabbits. Animals were exposed to a light source for 120 minutes and were sacrificed immediately or one week after exposure. Outer nuclear layer and neurosensory retina thickness measurements and photoreceptor counting were performed. Caspase-1 and caspase-3 were assessed by immunohistochemistry. Dihydroethidium was used to evaluate in situ generation of superoxide and thiobarbituric acid reactive substances were measured in retinal homogenates as indicators of lipid peroxidation. The total antioxidant capacity and oxidative ratio were also determined. Retinas from rabbits exposed to light showed higher levels of lipid peroxidation than the unexposed animals and a decrease in outer nuclear layer and neurosensory retina thickness. Our study dem...
Advances in Aging Research, 2013
Cells have intrinsic mechanisms for cleaning harmful oxidants represented mainly by reactive oxygen species (ROS). Despite the antioxidant defense, ROS can cause serious damage to the retina that with age leads to various eye diseases and even blindness. Among numerous cell sites of ROS generation, mitochondrial electron transport is of crucial importance. Recently, for the purpose of cleaning ROS in the mitochondrial matrix, powerful mitochondria-targeted antioxidant "SkQ1" has been invented. We studied SkQ1 effects upon tissues of rat posterior eye cup that consisted: retinal pigment epithelium (RPE) ↔ choroidal coat ↔ scleral coat. The eye cups were isolated from the eyes of adult albino rats and cultivated in rotary tissue culture system in the presence of 20 nM SkQ1 or without this compound. After 7 days -1 month in vitro eye cup samples were studied by immunohistochemistry, routine histology, morphometry, and digital image analysis. We have found that under chosen, "in vitro like in vivo" conditions 20 nM SkQ1 effectively reduced cell death in RPE and choroid, protected RPE from disintegration caused by cell phenotypic transformation and withdrawal from the layer, suppressed transmigration of choroidal coat cells. In the ex vivo model we used degenerative processes were more pronounced in the eye cup center where SkQ1 effect was most vivid. All this give us hopes for effectiveness of SkQ1 treatment of retinal central part that is very susceptible to light-induced over-oxidation injury and mostly suffering in many age-related diseases, AMD, in particular.
The Role of Oxidative Stress in the Onset and Development of Age-Related Macular Degeneration
Importance of Oxidative Stress and Antioxidant System in Health and Disease [Working Title]
Age-related macular degeneration (AMD) is a complex, degenerative and progressive chronic disease that leads to severe visual loss. The prevalence of early AMD accounts for 18% in the population between 65 and 74 years of age and even 30% in subjects older than 74 years. The articles published in the last decade point out to a significant role of oxidative stress in the onset and development of age-related macular degeneration. Generally, reactive oxygen species (ROS) are produced in the eye during light absorption and physiological metabolic processes. The level of oxidative stress is kept under control by the action of antioxidants and reparative enzymes. Excessive synthesis of ROS leads to increased oxidative modification of lipids, proteins and DNA, causing oxidative damage of cytoplasmic and nuclear cell elements and changes of the extracellular matrix. The accumulation of oxidatively modified compounds in drusen deposits will initiate the onset and development of AMD. The obje...
BMC Ophthalmology, 2018
Background: Cornea protects the eye against natural and anthropogenic ultraviolet (UV) damage and mechanical injury. Corneal incisions produced by UV lasers in ophthalmic surgeries are often complicated by oxidative stress and inflammation, which delay wound healing and result in vision deterioration. This study trialed a novel approach to prevention and treatment of iatrogenic corneal injuries using SkQ1, a mitochondria-targeted antioxidant approved for therapy of polyethiological dry eye disease. Methods: Rabbit models of UV-induced and mechanical corneal damage were employed. The animals were premedicated or treated with conjunctival instillations of 7.5 μM SkQ1. Corneal damage was assessed by fluorescein staining and histological analysis. Oxidative stress in cornea was monitored by measuring malondialdehyde (MDA) using thiobarbituric acid assay. Total antioxidant activity (AOA) was determined using hemoglobin/H 2 O 2 /luminol assay. Glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities were measured using colorimetric assays. Results: In both models corneas exhibited fluorescein-stained lesions, histologically manifesting as basal membrane denudation, apoptosis of keratocytes, and stromal edema, which were accompanied by oxidative stress as indicated by increase in lipid peroxidation and decline in AOA. The UV-induced lesions were more severe and long healing as corneal endothelium was involved and GPx and SOD were downregulated. The treatment inhibited loss of keratocytes and other cells, facilitated re-epithelialization and stromal remodeling, and reduced inflammatory infiltrations and edema thereby accelerating corneal healing approximately 2-fold. Meanwhile the premedication almost completely prevented development of UV-induced lesions. Both therapies reduced oxidative stress, but only premedication inhibited downregulation of the innate antioxidant activity of the cornea. Conclusions: SkQ1 efficiently prevents UV-induced corneal damage and enhances corneal wound healing after UV and mechanical impacts common to ocular surgery. Its therapeutic action can be attributed to suppression of mitochondrial oxidative stress, which in the first case embraces all corneal cells including epitheliocytes, while in the second case affects residual endothelial cells and stromal keratocytes actively working in wound healing. We suggest SkQ1 premedication to be used in ocular surgery for preventing iatrogenic complications in the cornea.
PLoS ONE, 2011
Background: Progression of age-related macular degeneration has been linked to iron dysregulation and oxidative stress that induce apoptosis of neural retinal cells. Since both antioxidants and chelating agents have been reported to reduce the progression of retinal lesions associated with AMD in experimental animals, the present study evaluates the ability of multi-functional antioxidants containing functional groups that can independently chelate redox metals and quench free radicals to protect the retina against light-induced retinal degeneration, a rat model of dry atrophic AMD.
Advances in Aging Research, 2012
Cells have intrinsic mechanisms for cleaning harmful oxidants represented mainly by reactive oxygen species (ROS). Despite the antioxidant defense, ROS can cause serious damage to the retina that with age leads to various eye diseases and even blindness. Among numerous cell sites of ROS generation, mitochondrial electron transport is of crucial importance. Recently, for the purpose of cleaning ROS in the mitochondrial matrix, powerful mitochondria-targeted antioxidant "SkQ1" has been invented. We studied SkQ1 effects upon tissues of rat posterior eye cup that consisted: retinal pigment epithelium (RPE) ↔ choroidal coat ↔ scleral coat. The eye cups were isolated from the eyes of adult albino rats and cultivated in rotary tissue culture system in the presence of 20 nM SkQ1 or without this compound. After 7 days-1 month in vitro eye cup samples were studied by immunohistochemistry, routine histology, morphometry, and digital image analysis. We have found that under chosen, "in vitro like in vivo" conditions 20 nM SkQ1 effectively reduced cell death in RPE and choroid, protected RPE from disintegration caused by cell phenotypic transformation and withdrawal from the layer, suppressed transmigration of choroidal coat cells. In the ex vivo model we used degenerative processes were more pronounced in the eye cup center where SkQ1 effect was most vivid. All this give us hopes for effectiveness of SkQ1 treatment of retinal central part that is very susceptible to light-induced over-oxidation injury and mostly suffering in many age-related diseases, AMD, in particular.
Change of redox status and modulation by thiol replenishment in retinal photooxidative damage
Investigative ophthalmology & visual science, 2002
Cellular or tissue reduction-oxidation (redox) is crucial in various diseases. The present study was conducted to analyze how tissue redox status is affected by photooxidative stress and whether the exogenous thiol antioxidant N-acetylcysteine (NAC) affects photooxidative stress-induced retinal damage. Mice were intraperitoneally injected with either NAC (250 mg/kg) or phosphate-buffered saline (PBS) and exposed to white fluorescent light (8000 lux) for 2 hours. Levels of thioredoxin (TRX), glutaredoxin (GRX), and glutathione (GSH), endogenous regulators of redox; 4-hydroxy-2-nonenal (HNE)-modified protein, a marker of lipid peroxidation; and nuclear factor (NF)-kappaB, a redox-sensitive transcription factor in retinal samples, was measured by immunohistochemistry and Western blot or enzymatic recycling assay. Light-induced retinal damage estimated by electroretinography and quantitative immunohistochemistry for 8-hydroxy-2-deoxyguanosine (8OHdG index), a marker of oxidative stress-...