Corneal alkali burns are potentially blinding injuries. Alkali induces oxidative stress in corneas followed by excessive corneal inflammation, neovascularization, and untransparent scar formation. Molecular hydrogen (H2), a potent reactive oxygen species (ROS) scavenger, suppresses oxidative stress and enables corneal healing when applied on the corneal surface. The purpose of this study was to examine whether the H2 pretreatment of healthy corneas evokes a protective effect against corneal alkali-induced oxidative stress. Rabbit eyes were pretreated with a H2 solution or buffer solution, by drops onto the ocular surface, and the corneas were then burned with 0.25 M NaOH. The results obtained with immunohistochemistry and pachymetry showed that in the corneas of H2-pretreated eyes, slight oxidative stress appeared followed by an increased expression of antioxidant enzymes. When these corneas were postburned with alkali, the alkali-induced oxidative stress was suppressed. This was in contrast to postburned buffer-pretreated corneas, where the oxidative stress was strong. These corneas healed with scar formation and neovascularization, whereas corneas of H2-pretreated eyes healed with restoration of transparency in the majority of cases. Corneal neovascularization was strongly suppressed. Our results suggest that the corneal alkali-induced oxidative stress was reduced via the increased antioxidant capacity of corneal cells against reactive oxygen species (ROS). It is further suggested that the ability of H2 to induce the increase in antioxidant cell capacity is important for eye protection against various diseases or external influences associated with ROS production.

• MeSH
• Alkalies toxicity   MeSH
• Antioxidants metabolism   MeSH
• Burns, Chemical drug therapy   metabolism   pathology   MeSH
• Epithelial Cells drug effects   metabolism   pathology   MeSH
• Wound Healing drug effects   MeSH
• Rabbits MeSH
• Disease Models, Animal MeSH
• Corneal Neovascularization prevention & control   MeSH
• Oxidative Stress drug effects   MeSH
• Eye Burns chemically induced   drug therapy   metabolism   pathology   MeSH
• Reactive Oxygen Species metabolism   MeSH
• Cornea blood supply   drug effects   metabolism   pathology   MeSH
• Hydrogen pharmacology   therapeutic use   MeSH
• Animals MeSH
• Check Tag
• Rabbits MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Retracted Publication MeSH
• Names of Substances
• Alkalies MeSH
• Antioxidants MeSH
• Reactive Oxygen Species MeSH
• Hydrogen MeSH

Our previous research revealed that trehalose, a nonreducing disaccharide of glucose and an important stress responsive factor, proved to have anti-inflammatory, antiapoptotic, and particularly antioxidant properties in UVB-irradiated corneas. Trehalose reduced oxidative stress in corneas induced by UVB irradiation, by means of a decrease in the antioxidant/prooxidant imbalance in the corneal epithelium. In this study, we demonstrate that trehalose of 3% or 6% concentration in eye drops directly decreases oxidative stress in UVB-irradiated corneas, by removing the excessive amount of reactive oxygen species (ROS). Trehalose drops applied on corneas during UVB irradiation once daily for four days resulted in a reduction or even absence of the oxidative stress, DNA damage, and peroxynitrite formation (detected by nitrotyrosine residues), seen in buffer-treated corneas. Furthermore, trehalose treatment applied curatively after repeated irradiation for the subsequent fourteen days led to the renewal of corneal transparency and significant suppression or even absence of neovascularization. This was in contrast to buffer-treated irradiated corneas, where the intracorneal inflammation was developed and the untransparent corneas were vascularized. In conclusion, the treatment of UVB-irradiated corneas with trehalose eye drops removed the excessive amount of ROS in the corneal epithelium, leading to the suppression of oxidative stress and favorable corneal healing. The 6% trehalose showed a higher intensive antioxidant effect.

• MeSH
• Wound Healing drug effects   radiation effects   MeSH
• Interleukin-1beta metabolism   MeSH
• Keratins metabolism   MeSH
• Rabbits MeSH
• Oxidative Stress * drug effects   radiation effects   MeSH
• Corneal Injuries drug therapy   MeSH
• DNA Damage MeSH
• Reactive Oxygen Species metabolism   MeSH
• Re-Epithelialization drug effects   radiation effects   MeSH
• Cornea drug effects   pathology   radiation effects   MeSH
• Nitric Oxide Synthase Type II metabolism   MeSH
• Trehalose pharmacology   therapeutic use   MeSH
• Tyrosine analogs & derivatives   metabolism   MeSH
• Ultraviolet Rays * MeSH
• Vascular Endothelial Growth Factor A metabolism   MeSH
• Animals MeSH
• Check Tag
• Rabbits MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Retracted Publication MeSH
• Names of Substances
• 3-nitrotyrosine MeSH Browser
• Interleukin-1beta MeSH
• Keratins MeSH
• Reactive Oxygen Species MeSH
• Nitric Oxide Synthase Type II MeSH
• Trehalose MeSH
• Tyrosine MeSH
• Vascular Endothelial Growth Factor A MeSH

The aim of this study is to examine whether molecular hydrogen (H2) is able to reduce oxidative stress after corneal damage induced by UVB irradiation. We previously found that UVB irradiation of the cornea caused the imbalance between the antioxidant and prooxidant enzymes in the corneal epithelium, followed by the imbalance between metalloproteinases and their physiological inhibitors (imbalances in favour of prooxidants and metalloproteinases) contributing to oxidative stress and development of the intracorneal inflammation. Here we investigate the effect of H2 dissolved in PBS in the concentration 0.5 ppm wt/vol, applied on rabbit corneas during UVB irradiation and healing (UVB doses 1.01 J/cm2 once daily for four days). Some irradiated corneas remained untreated or buffer treated. In these corneas the oxidative stress appeared, followed by the excessive inflammation. Malondiladehyde and peroxynitrite expressions were present. The corneas healed with scar formation and neovascularization. In contrast, in H2 treated irradiated corneas oxidative stress was suppressed and malondiladehyde and peroxynitrite expressions were absent. The corneas healed with the restoration of transparency. The study provides the first evidence of the role of H2 in prevention of oxidative and nitrosative stress in UVB irradiated corneas, which may represent a novel prophylactic approach to corneal photodamage.

• MeSH
• Rabbits MeSH
• Peroxynitrous Acid metabolism   MeSH
• Malondialdehyde metabolism   MeSH
• Oxidative Stress drug effects   radiation effects   MeSH
• Corneal Injuries drug therapy   metabolism   MeSH
• Reactive Oxygen Species metabolism   MeSH
• Cornea drug effects   metabolism   radiation effects   MeSH
• Ultraviolet Rays * MeSH
• Hydrogen therapeutic use   MeSH
• Animals MeSH
• Check Tag
• Rabbits MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Retracted Publication MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Peroxynitrous Acid MeSH
• Malondialdehyde MeSH
• Reactive Oxygen Species MeSH
• Hydrogen MeSH

The aim of this study was to examine the effect of molecular hydrogen (H2) on the healing of alkali-injured cornea. The effects of the solution of H2 in phosphate buffered saline (PBS) or PBS alone topically applied on the alkali-injured rabbit cornea with 0.25 M NaOH were investigated using immunohistochemical and biochemical methods. Central corneal thickness taken as an index of corneal hydration was measured with an ultrasonic pachymeter. Results show that irrigation of the damaged eyes with H2 solution immediately after the injury and then within next five days renewed corneal transparency lost after the injury and reduced corneal hydration increased after the injury to physiological levels within ten days after the injury. In contrast, in injured corneas treated with PBS, the transparency of damaged corneas remained lost and corneal hydration elevated. Later results-on day 20 after the injury-showed that in alkali-injured corneas treated with H2 solution the expression of proinflammatory cytokines, peroxynitrite, detected by nitrotyrosine residues (NT), and malondialdehyde (MDA) expressions were very low or absent compared to PBS treated injured corneas, where NT and MDA expressions were present. In conclusion, H2 solution favorably influenced corneal healing after alkali injury via suppression of oxidative stress.

• MeSH
• Actins metabolism   MeSH
• Cytokines metabolism   MeSH
• Gene Expression drug effects   MeSH
• Sodium Hydroxide toxicity   MeSH
• Immunohistochemistry MeSH
• Interleukin-1beta genetics   metabolism   MeSH
• Keratin-12 metabolism   MeSH
• Keratin-3 metabolism   MeSH
• Rabbits MeSH
• Peroxynitrous Acid metabolism   MeSH
• Malondialdehyde metabolism   MeSH
• Disease Models, Animal MeSH
• Oxidative Stress drug effects   MeSH
• Corneal Injuries etiology   metabolism   pathology   MeSH
• Cornea metabolism   pathology   MeSH
• Vascular Endothelial Growth Factor A genetics   metabolism   MeSH
• Hydrogen pharmacology   MeSH
• Animals MeSH
• Check Tag
• Rabbits MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Retracted Publication MeSH
• Names of Substances
• Actins MeSH
• Cytokines MeSH
• Sodium Hydroxide MeSH
• Interleukin-1beta MeSH
• Keratin-12 MeSH
• Keratin-3 MeSH
• Peroxynitrous Acid MeSH
• Malondialdehyde MeSH
• Vascular Endothelial Growth Factor A MeSH
• Hydrogen MeSH

The aim of this study was to examine whether mesenchymal stem cells (MSCs) and/or corneal limbal epithelial stem cells (LSCs) influence restoration of an antioxidant protective mechanism in the corneal epithelium and renewal of corneal optical properties changed after alkali burns. The injured rabbit corneas (with 0.25 N NaOH) were untreated or treated with nanofiber scaffolds free of stem cells, with nanofiber scaffolds seeded with bone marrow MSCs (BM-MSCs), with adipose tissue MSCs (Ad-MSCs), or with LSCs. On day 15 following the injury, after BM-MSCs or LSCs nanofiber treatment (less after Ad-MSCs treatment) the expression of antioxidant enzymes was restored in the regenerated corneal epithelium and the expressions of matrix metalloproteinase 9 (MMP9), inducible nitric oxide synthase (iNOS), α-smooth muscle actin (α-SMA), transforming growth factor-β1 (TGF-β1), and vascular endothelial factor (VEGF) were low. The central corneal thickness (taken as an index of corneal hydration) increased after the injury and returned to levels before the injury. In injured untreated corneas the epithelium was absent and numerous cells revealed the expressions of iNOS, MMP9, α-SMA, TGF-β1, and VEGF. In conclusion, stem cell treatment accelerated regeneration of the corneal epithelium, restored the antioxidant protective mechanism, and renewed corneal optical properties.

• MeSH
• Alkalies MeSH
• Antioxidants therapeutic use   MeSH
• Cell Differentiation drug effects   MeSH
• Burns, Chemical enzymology   genetics   pathology   therapy   MeSH
• Immunohistochemistry MeSH
• Rabbits MeSH
• Limbus Corneae cytology   MeSH
• Matrix Metalloproteinase 9 metabolism   MeSH
• Mesenchymal Stem Cells cytology   drug effects   MeSH
• Protective Agents pharmacology   therapeutic use   MeSH
• Corneal Pachymetry MeSH
• Gene Expression Regulation drug effects   MeSH
• Epithelium, Corneal pathology   MeSH
• Superoxide Dismutase metabolism   MeSH
• Nitric Oxide Synthase Type II metabolism   MeSH
• Transforming Growth Factor beta genetics   metabolism   MeSH
• Mesenchymal Stem Cell Transplantation * MeSH
• Adipocytes cytology   drug effects   MeSH
• Vascular Endothelial Growth Factor A metabolism   MeSH
• Corneal Opacity complications   therapy   MeSH
• Animals MeSH
• Check Tag
• Rabbits MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Retracted Publication MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Alkalies MeSH
• Antioxidants MeSH
• Matrix Metalloproteinase 9 MeSH
• Protective Agents MeSH
• Superoxide Dismutase MeSH
• Nitric Oxide Synthase Type II MeSH
• Transforming Growth Factor beta MeSH
• Vascular Endothelial Growth Factor A MeSH

Oxidative stress is involved in many ocular diseases and injuries. The imbalance between oxidants and antioxidants in favour of oxidants (oxidative stress) leads to the damage and may be highly involved in ocular aging processes. The anterior eye segment and mainly the cornea are directly exposed to noxae of external environment, such as air pollution, radiation, cigarette smoke, vapors or gases from household cleaning products, chemical burns from splashes of industrial chemicals, and danger from potential oxidative damage evoked by them. Oxidative stress may initiate or develop ocular injury resulting in decreased visual acuity or even vision loss. The role of oxidative stress in the pathogenesis of ocular diseases with particular attention to oxidative stress in the cornea and changes in corneal optical properties are discussed. Advances in the treatment of corneal oxidative injuries or diseases are shown.

• MeSH
• Alkalies toxicity   MeSH
• Ophthalmic Solutions therapeutic use   MeSH
• Oxidative Stress * drug effects   radiation effects   MeSH
• Corneal Injuries drug therapy   metabolism   pathology   MeSH
• Reactive Oxygen Species metabolism   MeSH
• Cornea drug effects   radiation effects   MeSH
• Ultraviolet Rays MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH
• Names of Substances
• Alkalies MeSH
• Ophthalmic Solutions MeSH
• Reactive Oxygen Species MeSH

BACKGROUND: Trehalose, a nonreducing disaccharide of glucose, is synthesized as a stress response factor when cells are exposed to stressful conditions. In the cornea, oxidative stress plays the key role in the development of acute corneal inflammatory response to UVB rays, photokeratitis. We found previously that trehalose reduced UVB-induced oxidative effects on the formation of cytotoxic peroxynitrite, apoptotic corneal epithelial cell death and changes in corneal optics. The aim of the present study was to examine whether trehalose might inhibit UVB-mediated proinflammatory cytokine and matrix metalloproteinase induction and the development of an antioxidant/pro-oxidant imbalance in the corneal epithelium, changes found previously to be strongly involved in the acute corneal UVB-induced inflammation. The expression of heat shock protein 70 as a potential biomarker for corneal UVB-induced damage was also examined. METHODS: The corneas of New Zealand white rabbits were irradiated with UVB rays, 312 nm, daily dose of 0.5 J/cm(2) for 4 days. During the irradiation, trehalose drops were applied on the right eye and buffered saline on the left eye. One day after the end of irradiations, the animals were killed and the corneas examined immunohistochemically for the expression of antioxidant enzymes (catalase, superoxide dismutase, glutathione peroxidase), pro-oxidant xanthine oxidoreductase/xanthine oxidase, proinflammatory cytokines (interleukin-6, interleukin-8), matrix metalloproteinase-9 and heat shock protein 70. RESULTS: After buffered saline treatment during UVB irradiation, an antioxidant/pro-oxidant imbalance appeared in the corneal epithelium: The expression of antioxidant enzymes was highly reduced, whereas the expression of pro-oxidant xanthine oxidase was increased. The pronounced expression of pro-inflammatory cytokines, matrix metalloproteinase and heat shock protein 70 was found in the UVB-irradiated corneal epithelium. Trehalose application significantly suppressed all the above-mentioned UVB-induced corneal disturbances. CONCLUSIONS: Trehalose favorably influenced the oxidative damage of the cornea caused by UVB rays. Trehalose suppressed proinflammatory cytokine induction. It is suggested that suppression of proinflammatory cytokines contributed strongly to reduced matrix metalloproteinase and xanthine oxidase expression in the UVB-irradiated corneal epithelium and to the decreased development of an antioxidant/pro-oxidant imbalance. The overexpression of heat shock protein 70 found in UVB-irradiated cornea after buffered saline treatment was reduced after trehalose application.

• MeSH
• Antioxidants MeSH
• Biomarkers metabolism   MeSH
• Cytokines metabolism   MeSH
• Radiation Injuries, Experimental drug therapy   enzymology   MeSH
• Immunoenzyme Techniques MeSH
• Rabbits MeSH
• Matrix Metalloproteinase 9 metabolism   MeSH
• Oxidative Stress drug effects   MeSH
• Oxidants MeSH
• Oxidoreductases metabolism   MeSH
• Image Processing, Computer-Assisted MeSH
• HSP70 Heat-Shock Proteins metabolism   MeSH
• Reactive Oxygen Species metabolism   MeSH
• Epithelium, Corneal enzymology   radiation effects   MeSH
• Trehalose pharmacology   MeSH
• Ultraviolet Rays adverse effects   MeSH
• Animals MeSH
• Check Tag
• Rabbits MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Antioxidants MeSH
• Biomarkers MeSH
• Cytokines MeSH
• Matrix Metalloproteinase 9 MeSH
• Oxidants MeSH
• Oxidoreductases MeSH
• HSP70 Heat-Shock Proteins MeSH
• Reactive Oxygen Species MeSH
• Trehalose MeSH