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
- alkálie toxicita MeSH
- antioxidancia metabolismus MeSH
- chemické popálení farmakoterapie metabolismus patologie MeSH
- epitelové buňky účinky léků metabolismus patologie MeSH
- hojení ran účinky léků MeSH
- králíci MeSH
- modely nemocí na zvířatech MeSH
- neovaskularizace rohovky prevence a kontrola MeSH
- oxidační stres účinky léků MeSH
- popálení oka chemicky indukované farmakoterapie metabolismus patologie MeSH
- reaktivní formy kyslíku metabolismus MeSH
- rohovka krevní zásobení účinky léků metabolismus patologie MeSH
- vodík farmakologie terapeutické užití MeSH
- zvířata MeSH
- Check Tag
- králíci MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- odvolaná publikace MeSH
- Názvy látek
- alkálie MeSH
- antioxidancia MeSH
- reaktivní formy kyslíku MeSH
- vodík MeSH
Oxidative stress is involved in many ocular diseases and injuries. The imbalance between oxidants and antioxidants in favour of oxidants (oxidative stress) leads to the damage and may be highly involved in ocular aging processes. The anterior eye segment and mainly the cornea are directly exposed to noxae of external environment, such as air pollution, radiation, cigarette smoke, vapors or gases from household cleaning products, chemical burns from splashes of industrial chemicals, and danger from potential oxidative damage evoked by them. Oxidative stress may initiate or develop ocular injury resulting in decreased visual acuity or even vision loss. The role of oxidative stress in the pathogenesis of ocular diseases with particular attention to oxidative stress in the cornea and changes in corneal optical properties are discussed. Advances in the treatment of corneal oxidative injuries or diseases are shown.
- MeSH
- alkálie toxicita MeSH
- oční roztoky terapeutické užití MeSH
- oxidační stres * účinky léků účinky záření MeSH
- poranění rohovky farmakoterapie metabolismus patologie MeSH
- reaktivní formy kyslíku metabolismus MeSH
- rohovka účinky léků účinky záření MeSH
- ultrafialové záření MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
- Názvy látek
- alkálie MeSH
- oční roztoky MeSH
- reaktivní formy kyslíku MeSH
The aim of this study was to investigate the effects of systemically administered bone-marrow-derived mesenchymal stromal cells (MSCs) on the early acute phase of inflammation in the alkali-burned eye. Mice with damaged eyes were either untreated or treated 24 h after the injury with an intravenous administration of fluorescent-dye-labeled MSCs that were unstimulated or pretreated with interleukin-1α (IL-1α), transforming growth factor-β (TGF-β), or interferon-γ (IFN-γ). Analysis of cell suspensions prepared from the eyes of treated mice on day 3 after the alkali burn revealed that MSCs specifically migrated to the damaged eye and that the number of labeled MSCs was more than 30-times higher in damaged eyes compared with control eyes. The study of the composition of the leukocyte populations within the damaged eyes showed that all types of tested MSCs slightly decreased the number of infiltrating lymphoid and myeloid cells, but only MSCs pretreated with IFN-γ significantly decreased the percentage of eye-infiltrating cells with a more profound effect on myeloid cells. Determining cytokine and NO production in the damaged eyes confirmed that the most effective immunomodulation was achieved with MSCs pretreated with IFN-γ, which significantly decreased the levels of the proinflammatory molecules IL-1α, IL-6, and NO. Taken together, the results show that systemically administered MSCs specifically migrate to the damaged eye and that IFN-γ-pretreated MSCs are superior in inhibiting the acute phase of inflammation, decreasing leukocyte infiltration, and attenuating the early inflammatory environment.
- MeSH
- alkálie toxicita MeSH
- alografty MeSH
- antivirové látky farmakologie MeSH
- chemické popálení patologie terapie MeSH
- interferon gama farmakologie MeSH
- interleukin-1alfa metabolismus MeSH
- myši inbrední BALB C MeSH
- myši MeSH
- nika kmenových buněk * MeSH
- popálení oka chemicky indukované metabolismus patologie terapie MeSH
- transformující růstový faktor beta metabolismus MeSH
- transplantace mezenchymálních kmenových buněk * MeSH
- zánět chemicky indukované metabolismus terapie MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- alkálie MeSH
- antivirové látky MeSH
- interferon gama MeSH
- interleukin-1alfa MeSH
- transformující růstový faktor beta MeSH
The efficacy of a chemically modified dextran - heparan sulfate mimicking regenerating agent (RGTA) on the healing of the rabbit cornea injured with alkali was examined. The eyes were injured with 0.15 N NaOH applied on the cornea or with 1.0 N NaOH using a 8 mm diameter filter paper disk. Then RGTA or placebo was applied on the cornea. In the last group of rabbits, corneas injured with the high alkali concentration were left without any treatment for four weeks; subsequently, the corneas were treated with RGTA or placebo. The central corneal thickness was measured using a pachymeter. The corneas were examined morphologically, immunohistochemically and for real time-PCR. Compared to control (unaffected) corneas, following the application of low alkali concentration the expression of urokinase-type plasminogen activator, metalloproteinase 9, nitric oxide synthase and xanthine oxidase was increased in the injured corneal epithelium of placebo-treated eyes, whereas the expression of antioxidant enzymes was reduced. Nitrotyrosine and malondialdehyde stainings appeared in the corneal epithelium. RGTA application suppressed the antioxidant/prooxidant imbalance and reduced the expression of the above-mentioned immunohistochemical markers. The corneal thickness increased after alkali injury, decreased during corneal healing after RGTA treatment faster than after placebo application. Following the injury with the high alkali concentration, corneal inflammation and neovascularization were highly pronounced in placebo-treated corneas, whereas in RGTA-treated corneas they were significantly supressed. When RGTA or placebo application was started later after alkali injury and corneas were ulcerated, subsequent RGTA treatment healed the majority of them. In conclusion, RGTA facilitates the healing of injured corneas via a reduction of proteolytic, oxidative and nitrosative damage.
- MeSH
- alkálie toxicita MeSH
- biopolymery MeSH
- glykosaminoglykany farmakologie MeSH
- hojení ran účinky léků MeSH
- imunohistochemie MeSH
- králíci MeSH
- kvantitativní polymerázová řetězová reakce MeSH
- modely nemocí na zvířatech MeSH
- molekulární mimikry MeSH
- oxidační stres účinky léků fyziologie MeSH
- poranění rohovky chemicky indukované terapie MeSH
- proteolýza účinky léků MeSH
- zvířata MeSH
- Check Tag
- králíci MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- alkálie MeSH
- biopolymery MeSH
- glykosaminoglykany MeSH
- OTR4120 MeSH Prohlížeč
The purpose of this study was to investigate whether rabbit bone marrow-derived mesenchymal stem cells (MSCs) effectively decrease alkali-induced oxidative stress in the rabbit cornea. The alkali (0.15 N NaOH) was applied on the corneas of the right eyes and then rinsed with tap water. In the first group of rabbits the injured corneas remained untreated. In the second group MSCs were applied on the injured corneal surface immediately after the injury and eyelids sutured for two days. Then the sutures were removed. In the third group nanofiber scaffolds seeded with MSCs (and in the fourth group nanofibers alone) were transferred onto the corneas immediately after the injury and the eyelids sutured. Two days later the eyelid sutures were removed together with the nanofiber scaffolds. The rabbits were sacrificed on days four, ten or fifteen after the injury, and the corneas were examined immunohistochemically, morphologically, for the central corneal thickness (taken as an index of corneal hydration) using an ultrasonic pachymeter and by real-time PCR. Results show that in untreated injured corneas the expression of malondialdehyde (MDA) and nitrotyrosine (NT) (important markers of lipid peroxidation and oxidative stress) appeared in the epithelium. The antioxidant aldehyde dehydrogenase 3A1 (ALDH3A1) decreased in the corneal epithelium, particularly in superficial parts, where apoptotic cell death (detected by active caspase-3) was high. (In control corneal epithelium MDA and NT are absent and ALDH3A1 highly present in all layers of the epithelium. Cell apoptosis are sporadic). In injured untreated cornea further corneal disturbances developed: The expressions of matrix metalloproteinase 9 (MMP9) and proinflammatory cytokines, were high. At the end of experiment (on day 15) the injured untreated corneas were vascularized and numerous inflammatory cells were present in the corneal stroma. Vascular endothelial growth factor (VEGF) expression and number of macrophages were high. The results obtained in injured corneas covered with nanofiber scaffolds alone (without MSCs) or in injured corneas treated with MSCs only (transferred without scaffolds) did not significantly differ from the results found in untreated injured corneas. In contrast, in the injured corneas treated with MSCs on nanofiber scaffolds, ALDH3A1 expression remained high in the epithelium (as in the control cornea) and positive expression of the other immunohistochemical markers employed was very low (MMP9) or absent (NT, MDA, proinflammatory cytokines), also similarly as in the control cornea. Corneal neovascularization and the infiltration of the corneal stroma with inflammatory cells were significantly suppressed in the injured corneas treated with MSCs compared to the untreated injured ones. The increased central corneal thickness together with corneal opalescency appearing after alkali injury returned to normal levels over the course of ten days only in the injured corneas treated with MSCs on nanofiber scaffolds. The expression of genes for the proinflammatory cytokines corresponded with their immunohistochemical expression. In conclusion, MSCs on nanofiber scaffolds protected the formation of toxic peroxynitrite (detected by NT residues), lowered apoptotic cell death and decreased matrix metalloproteinase and pro-inflammatory cytokine production. This resulted in reduced corneal inflammation as well as neovascularization and significantly accelerated corneal healing.
- Klíčová slova
- alkali-induced oxidative stress, central corneal thickness, immunohistochemistry, rabbit cornea, rabbit mesenchymal stem cells, real-time PCR,
- MeSH
- alkálie toxicita MeSH
- chemické popálení patologie chirurgie MeSH
- hojení ran MeSH
- králíci MeSH
- mezenchymální kmenové buňky cytologie MeSH
- modely nemocí na zvířatech MeSH
- nanovlákna terapeutické užití MeSH
- oxidační stres * MeSH
- poranění rohovky MeSH
- rohovka patologie chirurgie MeSH
- tkáňové podpůrné struktury * MeSH
- transplantace mezenchymálních kmenových buněk metody MeSH
- zvířata MeSH
- Check Tag
- králíci MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
- Názvy látek
- alkálie MeSH
In order to contribute to a better understanding of the role of leukocyte elastase in corneal melting after a severe alkali burn, the in situ appearance and activity of this enzyme in the rabbit cornea was examined. For this reason, a histochemical approach using cryostat sections on membranes and a gel incubation medium with the very sensitive substrate Mu-Ala-Ala-Pro-Val-7-amino-4-trifluoromethylcoumarin (Enzyme Systems Products, Livermore, Calif., USA) was employed. In contrast to the normal rabbit cornea where leukocyte elastase activity was absent, in alkali-burned cornea a high enzyme activity in inflammatory cells (particularly polymorphonuclear leukocytes) was present. The extracellular release of leukocyte elastase into the substantia propria of the corneal stroma was associated with disintegration of the corneal stroma and the appearance of corneal ulcers. These results show that leukocyte elastase is associated with corneal destruction after a severe alkali burn.
- MeSH
- alkálie toxicita MeSH
- chemické popálení enzymologie patologie MeSH
- extracelulární prostor enzymologie MeSH
- fluorescenční mikroskopie MeSH
- králíci MeSH
- kumariny MeSH
- leukocytární elastasa metabolismus MeSH
- modely nemocí na zvířatech MeSH
- popálení oka chemicky indukované enzymologie patologie MeSH
- poranění rohovky MeSH
- rohovka enzymologie patologie MeSH
- senzitivita a specificita MeSH
- substrátová specifita MeSH
- zvířata MeSH
- Check Tag
- králíci MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- 7-amino-4-trifluoromethylcoumarin MeSH Prohlížeč
- alkálie MeSH
- kumariny MeSH
- leukocytární elastasa MeSH
