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

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

Trehalose, a disaccharide of glucose, is a naturally occurring nontoxic and nonreducing bioactive sugar. Trehalose is synthetized by many organisms when cells are exposed to stressful conditions, including dehydration, heat, oxidation, hypoxia or even anoxia. Although trehalose is not synthesized by mammalian cells, it has recently been demonstrated to have a number of important properties that indicate its utility in humans. Trehalose enables wound healing by protecting cells, especially cell membranes, from oxidative injury and dessication. When the injured cornea is treated with trehalose, corneal inflammation, scar formation and corneal neovascularization are suppressed. In dry eye disease, trehalose decreased cell apoptosis and reduced oxidative, inflammatory and proteolytic activity at the ocular surface. In UVB irradiated cornea, trehalose suppressed photodamage evoked by UVB rays. It decreased the intracorneal inflammation and reduced corneal neovascularization. Trehalose prevented postoperative fibrous scar formation after ocular surgery, such as glaucoma filtration surgery. The non-toxicity of trehalose allows its administration in humans for extended periods and enables its use in various disease states.

• MeSH
• Anti-Inflammatory Agents chemistry   pharmacology   MeSH
• Antioxidants chemistry   pharmacology   MeSH
• Apoptosis * MeSH
• Wound Healing * MeSH
• Clinical Trials as Topic MeSH
• Rabbits MeSH
• Humans MeSH
• Disease Models, Animal MeSH
• Ophthalmology MeSH
• Oxidative Stress * MeSH
• Cornea drug effects   radiation effects   MeSH
• Dry Eye Syndromes drug therapy   MeSH
• Trehalose chemistry   pharmacology   MeSH
• Ultraviolet Rays MeSH
• Animals MeSH
• Check Tag
• Rabbits MeSH
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Review 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

• MeSH
• Acute Disease MeSH
• Blepharospasm diagnosis   etiology   veterinary   MeSH
• Eye Foreign Bodies * diagnosis   therapy   veterinary   MeSH
• Cats MeSH
• Rabbits MeSH
• Guinea Pigs MeSH
• Corneal Injuries * diagnosis   etiology   prevention & control   veterinary   MeSH
• Dogs MeSH
• Foreign-Body Reaction veterinary   MeSH
• Animals MeSH
• Check Tag
• Cats MeSH
• Rabbits MeSH
• Guinea Pigs MeSH
• Dogs MeSH
• Animals MeSH
• Publication type
• Case Reports 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

The Purpose of present study was to investigate the effect of riboflavin/ultraviolet-A-induced collagen cross-linking (CXL) on central cornea, limbus and intraocular pressure (IOP). This was an animal experimental study. The right corneas of 10 rabbits were ultraviolet-A irradiated (3 mW/cm2 for 30 minutes) after de-epithelialization and instillation of 0.1% riboflavin / 20% Dextran drops. Left corneas served as controls. Samples were examined histologically one month postoperatively. Before and after treatment, IOP measurements were recorded bilaterally. At central cornea of eyes underwent CXL keratocyte repopulation, normal arrangement of collagen fibres and a statistically significant change in fibres diameter were detected, compared to controls. At limbus area, there were not any significant histological differences after CXL. There was no statistically significant difference between pre- and postoperative IOP in all eyes.

• MeSH
• Photosensitizing Agents pharmacology   MeSH
• Collagen chemistry   ultrastructure   MeSH
• Rabbits MeSH
• Limbus Corneae drug effects   radiation effects   surgery   ultrastructure   MeSH
• Intraocular Pressure * drug effects   radiation effects   MeSH
• Cross-Linking Reagents pharmacology   MeSH
• Riboflavin pharmacology   MeSH
• Cornea drug effects   radiation effects   surgery   ultrastructure   MeSH
• Ultraviolet Rays * MeSH
• Animals MeSH
• Check Tag
• Rabbits MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH

In this study we tried to develop a new approach to suppress inflammation and neovascularization in the alkali-injured rabbit cornea. For this reason Cyclosporine A (CsA)-loaded electrospun nanofibers were transferred onto the ocular surface injured with alkali (0.25 N NaOH). Damaged corneas were divided into the following groups: untreated, treated with CsA eye drops, treated with nanofibers drug-free and treated with CsA-loaded nanofibers. Healthy rabbit corneas served as controls. Drug-free nanofibers and CsA-loaded nanofibers were transferred onto the damaged corneal surface immediately after the injury and sutured to conjunctiva. On day five after the injury the nanofibers were removed. The animals from all groups were sacrificed on day twelve after the injury. The extent of the inflammatory reaction and corneal healing were examined macroscopically, immunohistochemically and biochemically. The central corneal thickness was measured using an ultrasonic pachymeter. When compared with untreated injured corneas, injured corneas treated with drug-free nanofibers or injured corneas treated with CsA eye drops, the number of CD3-positive cells (T lymphocytes) and the production of pro-inflammatory cytokines were strongly reduced in corneas treated with CsA-loaded nanofibers, which was associated with the significantly decreased expression of matrix metalloproteinase 9, inducible nitric oxide synthase, vascular endothelial growth factor and active caspase-3. CsA-loaded nanofibers effectively suppressed corneal inflammation and corneal neovascularization. Central corneal thickness restored to levels before injury only in corneas treated with CsA-loaded nanofibers. Corneal transparency was highly restored in these corneas. It is suggested that the beneficial effect of CsA-loaded nanofibers was associated with the continuous release of CsA from nanofibers and continuous affection of damaged cornea by CsA. The suture of nanofibers to conjunctiva and the closed eyes contributed to beneficial corneal healing. This is in contrast to CsA eye drops, which are quickly washed from the ocular surface and the contact of CsA with the damaged cornea was limited. In conclusion, the approach with CsA-loaded nanofibers could represent an effective alternative mode of therapy for corneal chemical burns.

• MeSH
• Alkalies adverse effects   MeSH
• Burns, Chemical drug therapy   MeSH
• Cyclosporine administration & dosage   therapeutic use   MeSH
• Immunohistochemistry MeSH
• Immunosuppressive Agents therapeutic use   MeSH
• Caspase 3 metabolism   MeSH
• Rabbits MeSH
• Disease Models, Animal MeSH
• Nanofibers MeSH
• Corneal Neovascularization pathology   MeSH
• Eye Burns drug therapy   metabolism   pathology   MeSH
• Corneal Injuries chemically induced   metabolism   pathology   MeSH
• T-Lymphocytes pathology   MeSH
• Vascular Endothelial Growth Factor A metabolism   MeSH
• Animals MeSH
• Check Tag
• Rabbits MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH

The aim of this study was to examine whether nanofiber scaffolds seeded with rabbit bone marrow mesenchymal stem cells (MSCs nanofibers) transferred onto the damaged corneal surface and covered with cyclosporine A (CsA)-loaded nanofiber scaffolds (CsA nanofibers) enable healing of the rabbit cornea injured with 1N NaOH. The healing of damaged corneas was examined morphologically, immunohistochemically and biochemically on day 24 after the injury. Compared to untreated injured corneas, where corneal ulceration or large corneal thinning or even perforation were developed, injured corneas treated with drug free nanofibers healed without profound disturbances in a majority of cases, although with fibrosis and scar formation. In injured corneas treated with CsA nanofibers or MSCs nanofibers, the development of scar formation was reduced. Best healing results were obtained with a combination of MSCs and CsA nanofibers (MSCs-CsA nanofibers). Corneas healed with highly restored transparency. Neovascularization highly expressed in untreated injured corneas and reduced in corneas treated with CsA nanofibers or MSCs nanofibers, was suppressed in corneas treated with MSCs-CsA nanofibers. The levels of matrix metalloproteinase 9, inducible nitric oxide synthase, interleukin 6, α-smooth muscle actin, tumor growth factor β and vascular endothelial growth factor were significantly decreased in these corneas as compared to untreated corneas, where the levels of the above mentioned markers were high. In conclusion, MSCs-CsA nanofibers were effective in the treatment of severe alkali-induced corneal injury.

• MeSH
• Cyclosporine administration & dosage   MeSH
• Wound Healing drug effects   MeSH
• Sodium Hydroxide toxicity   MeSH
• Immunosuppressive Agents administration & dosage   MeSH
• Cicatrix prevention & control   MeSH
• Caustics toxicity   MeSH
• Rabbits MeSH
• Drug Delivery Systems methods   MeSH
• Disease Models, Animal MeSH
• Nanofibers MeSH
• Corneal Neovascularization prevention & control   MeSH
• Drug Carriers MeSH
• Corneal Injuries therapy   MeSH
• Tissue Scaffolds MeSH
• Mesenchymal Stem Cell Transplantation methods   MeSH
• Animals MeSH
• Check Tag
• Rabbits MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article 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
• Research Support, Non-U.S. Gov't MeSH