8-hydroxy-2--deoxyguanosine and Corneal-Injuries

We compared the therapeutic effects of topical 8-oxo-2'-deoxyguanosine (8-oxo-dG) and corticosteroid in a murine ocular alkali burn model. (n = 128) The corneal alkali burn model was established by applying 0.1 N sodium hydroxide (NaOH), followed by treatment with 8-oxo-dG, 0.1% fluorometholone (FML), 1% prednisolone acetate (PDE), or phosphate-buffered saline (PBS) twice daily. One week later, the clinical and histological status of the cornea were assessed. Transcript levels of inflammatory cytokines and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase as well as the levels of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in the cornea, were assayed. The 8-oxo-dG and PDE groups showed marked improvements in corneal integrity and clarity when compared with the PBS group (each p < 0.01). The numbers of cells stained for neutrophil elastase and F4/80-positive inflammatory cells were significantly decreased, with levels of interleukin(IL)-1β, IL-6, tumor necrosis factor(TNF)-α, and total ROS/RNS amounts markedly reduced in the 8-oxo-dG, FML, and PDE groups (each p < 0.05). Levels of NADPH oxidase type 2 and 4 were substantially more repressed in the 8-oxo-dG-treated group than in the PDE-treated group (each p < 0.05). Topical 8-oxo-dG showed excellent therapeutic effects that were comparable with those treated with topical PDE in a murine ocular alkali burn model.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Administration, Ophthalmic; Animals; Burns, Chemical; Corneal Injuries; Drug Evaluation, Preclinical; Eye Burns; Female; Fluorometholone; Glucocorticoids; Mice, Inbred BALB C; Sodium Hydroxide

Oxidative stress may cause ocular surface damage during the development of dry eye. Mammalian cells have defense systems against oxidative stress. A central regulator of the stress response is nuclear factor-erythroid 2-related factor 2 (NFE2L2). NFE2L2 is activated by the novel triterpenoid RS9 (a biotransformation compound of RTA 402). The purpose of this study was to assess the efficacy of RS9 against dry eye using in vitro and in vivo models. Bioactivity was estimated by the induction of mRNAs for two NFE2L2-targeted genes: NQO1 (prevents radical species) and GCLC (glutathione synthesis), using a corneal epithelial cell line (HCE-T). Protection against oxidation and cell damage was tested in vitro by culturing cells under hyperosmotic stress or by the addition of menadione, a generator of reactive oxygen species (ROS). Dry eye in vivo was induced by the injection of scopolamine into rats. Then, 930 nM of RS9 was applied to both eyes for 2 weeks. Oxidative stress was measured by the accumulation of 8-hydroxy-2'-deoxyguanosine (8-OHdG). Corneal wound healing was measured by scoring for superficial punctate keratitis (SPK). Corneal epithelial cell densities were evaluated histologically. RS9 and RTA 402 induced the expression of NQO1 and GCLC mRNAs in HCE-T cells. And both compounds suppressed hyperosmotic-ROS generation and menadione induced cellular damage. However RS9 had a stronger protective effect than RTA 402. Ocular instillation of RS9 also significantly upregulated the expression of Nqo1 mRNA in the corneal epithelium. Accumulation of 8-OHdG, increase of SPK scores and decrement of basal cell density were observed in corneal epithelium from scopolamine-injected rats. These changes were significantly ameliorated by the topical administration of RS9. RS9 induced Nfe2l2 activation and Nfe2l2-targeted genes, reduced oxidation, and ameliorated symptoms of dry eye using in vitro and in vivo models. Thus, RS9 might be a potent candidate agent against dry eye disease.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Animals; Corneal Injuries; Disease Models, Animal; Dry Eye Syndromes; Epithelial Cells; Epithelium, Corneal; Gene Expression Regulation; Glutamate-Cysteine Ligase; Humans; Keratitis; NAD(P)H Dehydrogenase (Quinone); NF-E2-Related Factor 2; Oxidative Stress; Rats; Reactive Oxygen Species; RNA, Messenger; Scopolamine; Triterpenes; Wound Healing

To evaluate the therapeutic effects of topical 8-oxo-2'-deoxyguanosine (8-oxo-dG) on experimental ocular chemical injury models.. We created ocular chemical injury models with 8-week-old BALB/c mice (n = 70) by applying 100% ethanol; the mice were then treated with 8-oxo-dG eye drops 10 and 5 mg/mL and phosphate-buffered saline (PBS) twice daily. After 7 days, clinical findings such as corneal integrity, clarity, and neovascularization were assessed. Histology, immunohistochemistry findings, and inflammatory cytokine levels using real-time polymerase chain reactions in the corneas of the mice were also analyzed.. Topical application of 8-oxo-dG eye drops resulted in a significant improvement of epithelial defects and clarity, dose dependently (each P < 0.001). Inflammatory cell infiltration and corneal stromal edema were also decreased in the 8-oxo-dG-treated mice compared with PBS-treated controls, based on hematoxylin and eosin staining. The expressions of F4/80 and neutrophil elastase-positive inflammatory cells and IL-1 and TNF-α cytokine levels were significantly reduced in the 8-oxo-dG group compared with the PBS group (each P < 0.01).. Topical 8-oxo-dG application showed an excellent therapeutic effect in ocular chemical injury models by suppressing inflammation.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Analysis of Variance; Animals; Burns, Chemical; Cornea; Corneal Injuries; Corneal Neovascularization; Corneal Stroma; Cytokines; Deoxyguanosine; Disease Models, Animal; Epithelium, Corneal; Ethanol; Eye Burns; Male; Mice; Mice, Inbred BALB C; Ophthalmic Solutions

Pigment epithelium-derived factor (PEDF) a glycoprotein that belongs to the superfamily of serine protease inhibitors, has been recently shown to be the most potent inhibitor of angiogenesis in the mammalian eye. However, which active domain of PEDF protein could be involved in its anti-angiogenic properties remains unknown. Therefore, in this study, we examined which PEDF-derived synthetic peptides could inhibit corneal neovascularization induced by chemical cauterization in vivo. Rats treated with topical application of PEDF protein had 31% less corneal neovascularization at day 7 after the injury than phosphate-buffered saline (PBS)-treated rats. P5-2 and P5-3 peptides (residues 388-393 and 394-400 of PEDF protein, respectively) significantly suppressed the corneal neovascularization after chemical cauterization at day 7, and its anti-angiogenic potential was almost equal to that of full-length PEDF protein. Further, full-length PEDF protein and P5-3 peptide significantly decreased 8-hydroxy-2'-deoxyguanosine and vascular endothelial growth factor (VEGF) levels in the corneal. Our present study suggests that PEDF-derived synthetic peptide, P5-3 could inhibit the corneal neovascularization induced by chemical cauterization in rats by suppressing VEGF expression via its anti-oxidative properties.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Administration, Topical; Angiogenesis Inhibitors; Animals; Cautery; Cornea; Corneal Injuries; Corneal Neovascularization; Deoxyguanosine; Disease Models, Animal; Eye Proteins; Male; Nerve Growth Factors; Rats; Rats, Sprague-Dawley; Serpins; Vascular Endothelial Growth Factor A