An Immunohistochemical Study of the Increase in Antioxidant Capacity of Corneal Epithelial Cells by Molecular Hydrogen, Leading to the Suppression of Alkali-Induced Oxidative Stress

Abstract

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.

Retraction Note: Therapeutic effect of molecular hydrogen in corneal UVB-induced oxidative stress and corneal photodamage

“…An institutional investigation found evidence that the H2 condition for Figure 3B has been duplicated from Figure 5C of an article previously published by Cejka et al (2016) 1 and the day 4 H2 condition for Figure 4A has been duplicated from Figure 3 of an article published later by Cejka et al (2020) 2 . The authors have not been able to provide all the relevant raw data on request.…”

Ferrostatin‐1‐loaded liposome for treatment of corneal alkali burn via targeting ferroptosis

“…Further, it has been well documented that alkali burns promote the accumulation of reactive oxygen species (ROS) in the cornea 24–27 . Following a severe corneal injury, oxidative stress could lead to an antioxidant/prooxidant imbalance in corneal cells.…”

Retracted: An Immunohistochemical Study of the Increase in Antioxidant Capacity of Corneal Epithelial Cells by Molecular Hydrogen, Leading to the Suppression of Alkali-Induced Oxidative Stress

“…Oxidative Medicine and Cellular Longevity has retracted the article titled “An Immunohistochemical Study of the Increase in Antioxidant Capacity of Corneal Epithelial Cells by Molecular Hydrogen, Leading to the Suppression of Alkali-Induced Oxidative Stress” [ 1 ], due to concerns with the figures. The journal was contacted by a reader who identified that Figure 4(j) in [ 1 ] is duplicated with Figure 5(c) in [ 2 ], and Figure 5(a) in [ 3 ]. Additionally panel 4 of Figure 3 in [ 1 ] is duplicated with the H2, Day 4 panel of Figure 4(a) in a now retracted article [ 4 ].…”

“…The journal was contacted by a reader who identified that Figure 4(j) in [ 1 ] is duplicated with Figure 5(c) in [ 2 ], and Figure 5(a) in [ 3 ]. Additionally panel 4 of Figure 3 in [ 1 ] is duplicated with the H2, Day 4 panel of Figure 4(a) in a now retracted article [ 4 ].…”