8-hydroxy-2--deoxyguanosine and Corneal-Diseases

The Tet-mev-1 mouse expressing a mitochondrial complex-II mutated SDHC(V69E) gene controlled by a tetracycline (Tet)-On/Off system can overproduce O(2)(·-) and is a versatile whole-animal model for studying mitochondrial oxidative stress. Here we report a series of age-dependent variations in corneal epithelium, endothelium, and parenchymal cells of the Tet-mev-1 mice relative to wild-type C57BL/6j mice.. Measurements of (1) mitochondrial electron transport enzyme activities; (2) O(2)(·-) production; (3) carbonylated protein, and 8-hydroxydeoxyguanosine (8-OHdG) levels as markers of oxidative stress; (4) pathologic analyses under optical and electron microscopy; (5) hematoxylin-eosin or toluidine-blue staining; and (6) immunohistochemistry with an anti-β-catenin antibody were performed in the eye, especially the cornea.. Complex II-III activity was decreased by electron leakage between complex II and CoQ. This resulted in increased age-dependent intracellular oxidative stress in the eye of Tet-mev-1 mice. Corneal epithelialization was delayed in Tet-mev-1 mice after 20% ethanol treatment, as the number of cells and mitotic cells decreased in the corneal epithelium of Tet-mev-1 mice compared with that of wild type. The age-dependent decrease in cell number accelerated in the corneal endothelium cells. Moreover, it was suggested that the corneal thickness was decreased by thinning of parenchymal cells with age in Tet-mev-1 mice.. These results suggest that mitochondrial oxidative stress with electron transport chain dysfunction can influence pathogenesis and progression of age-related corneal diseases, as well as generalized corneal aging acceleration.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Aging; Animals; Blotting, Western; Caenorhabditis elegans Proteins; Catalase; Cell Count; Corneal Diseases; Cytochromes b; Deoxyguanosine; Electron Transport Complex II; Endothelium, Corneal; Fluorescent Antibody Technique, Indirect; Mice; Mice, Inbred C57BL; Mice, Transgenic; Microscopy, Electron; Microscopy, Fluorescence; Mitochondria; Oxidative Stress; Protein Carbonylation; Succinate Dehydrogenase; Superoxides; Tetracycline

The purpose of the experiment reported here was to assess the involvement of advanced glycation end products (AGEs), oxidative stress, and nuclear factor kappa-B (NF-κB) activation in the development of diabetic keratopathy.. Diabetes was induced by intraperitoneal streptozotocin injection in male Sprague-Dawley rats. The thickness of the cornea was measured. Apoptosis was detected by TUNEL assay and western blot for caspase-3. The expression of AGEs and 8-hydroxydeoxyguanosine (8-OHdG) were studied by immunohistochemistry in corneal tissues of normoglycaemic and diabetic rats. NF-κB activation was evaluated by electrophoretic mobility shift assay and southwestern histochemistry.. Corneal edema was observed in diabetic rats. The thickness of cornea was higher in diabetic than in control rats. AGEs were accumulated in corneal tissues. 8-OHdG and NF-κB were identified in corneal epithelium, stroma and endothelium, and its expressions were greater in diabetic than in those of control rats. Diabetes induces significant alterations in rat corneal tissue structure.. The higher expression of AGE, 8-OHdG and NF-κB in corneal tissues of diabetic rats suggests that these factors are involved in apoptosis and in subsequent corneal alterations related to diabetic keratopathy.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Animals; Apoptosis; Blotting, Western; Corneal Diseases; Corneal Stroma; Deoxyguanosine; Diabetes Complications; Diabetes Mellitus, Experimental; DNA Damage; Electrophoretic Mobility Shift Assay; Endothelium, Corneal; Epithelium, Corneal; Glycation End Products, Advanced; Immunohistochemistry; In Situ Nick-End Labeling; Male; NF-kappa B; Oxidative Stress; Rats; Rats, Sprague-Dawley

To analyze whether rebamipide (REB) and carteolol hydrochloride (CH) protect against UVB-induced corneal damage in mice.. BALB/c mice topically pretreated with REB (1 and 10 mM) or CH (1, 10, and 100 mM) were exposed to ultraviolet (UV) B light at 416 micro W/cm(2). To evaluate corneal damage, mire irregularity was graded, and the haze index was estimated by using digitized corneal images. The formation of oxidized DNA in the corneal epithelium resulting from UVB exposure was estimated by using quantitative immunohistochemistry for 8-hydroxy-2-deoxyguanosine (8OHdG index). To analyze the mechanism of cytoprotection by REB and CH against UVB-induced cell damage, the UV absorption spectrum in these agents was evaluated by spectrophotometry, and their hydroxyl radical scavenging effect was evaluated by the electron spin resonance (ESR) spin trapping technique with Fenton system hydroxy radical generation.. Seventy-two hours after UVB exposure, the severity of mire irregularity, haze index, and 8OHdG index were significantly lower in mice pretreated with 10 mM (P < 0.05, P < 0.05, and P < 0.01, respectively) of REB and in mice pretreated with 10 mM (P < 0.05, P < 0.01, and P < 0.01, respectively) and 100 mM (P < 0.01, P < 0.01, and P < 0.01, respectively) of CH compared with mice treated with vehicle. The absorption spectrum of REB overlapped with the UVB wavelength, and that of CH overlapped partially. The ESR spin signal corresponding to the hydroxyl radical was reduced by the addition of REB or CH.. REB and CH attenuate UVB-induced corneal damage, which may be partly responsible for their sunscreening and hydroxyl radical scavenging effects.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adrenergic beta-Antagonists; Alanine; Animals; Anti-Ulcer Agents; Carteolol; Cornea; Corneal Diseases; Cytoprotection; Deoxyguanosine; Electron Spin Resonance Spectroscopy; Immunoenzyme Techniques; Male; Mice; Mice, Inbred BALB C; Quinolones; Radiation Injuries, Experimental; Ultraviolet Rays