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

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