RESUMO
BACKGROUND: Increasing evidence suggests that glaucoma affects the ocular surface. We aimed to investigate the cellular mechanisms underlying the glaucoma-associated corneal alterations in an animal model. METHODS: Wistar rats underwent the cauterization of two episcleral veins of the left eye to elevate the intraocular pressure (ipsilateral, G-IL). Control animals received a sham procedure (C-IL). Contralateral eyes did not receive any procedure (G-CL or C-CL). Enzymes related to the redox status, oxidative damage to macromolecules, and inflammatory markers were assessed in corneal lysates. RESULTS: Compared to C-IL, NOX4, NOX2, and iNOS expression was increased in G-IL (68%, p < 0.01; 247%, p < 0.01; and 200%, p < 0.001, respectively). We found an increase in SOD activity in G-IL (60%, p < 0.05). The GSH/GSSG ratio decreased in G-IL (80%, p < 0.05), with a decrease in GR activity (40%, p < 0.05). G-IL displayed oxidative (90%, p < 0.01) and nitrosative (40%, p < 0.05) protein damage, and enhanced lipid peroxidation (100%, p < 0.01). G-IL group showed an increased in CD45, CD68 and F4/80 expression (50%, p < 0.05; 190%, p < 0.001 and 110%, p < 0.05, respectively). G-CL displayed a higher expression of Nrf2 (60%, p < 0.001) and increased activity of SOD, CAT, and GPx (60%, p < 0.05; 90%, p < 0.01; and 50%, p < 0.05, respectively). CONCLUSIONS: Glaucoma induces a redox imbalance in the ipsilateral cornea with an adaptive response of the contralateral one. GENERAL SIGNIFICANCE: Our study provides a possible mechanism involving oxidative stress and inflammation that explains the corneal alterations observed in glaucoma. We demonstrate that these changes extend not only to the ipsilateral but also to the contralateral cornea.
Assuntos
Glaucoma , Ratos , Animais , Ratos Wistar , Estresse Oxidativo/fisiologia , Oxirredução , Córnea/metabolismo , Superóxido Dismutase/metabolismoRESUMO
The aim of the study was to evaluate the time course of the effects of urban air pollutants on the ocular surface, focusing on the morphological changes, the redox balance, and the inflammatory response of the cornea. 8-week-old mice were exposed to urban or filtered air (UA-group and FA-group, respectively) in exposure chambers for 1, 2, 4, and 12â¯weeks. After each time, the eyes were enucleated and the corneas were isolated for biochemical analysis. UA-group corneas exhibited a continuous increase in NADPH oxidase-4 levels throughout the exposure time, suggesting an increased production of reactive oxygen species (ROS). After 1â¯week, an early adaptive response to ROS was observed as an increase in antioxidant enzymes. After 4â¯weeks, the enzymatic antioxidants were decreased, meanwhile an increase of the glutathione was shown, as a later compensatory antioxidant response. However, redox imbalance took place, evidenced by the increased oxidized proteins, which persisted up to 12â¯weeks. At this time point, corneal epithelium hyperplasia was also observed. The inflammatory response was modulated by the increase in IL-10 levels after 1â¯week, which early regulates the release of TNF-α and IL-6. These results suggest that air pollution alters the ocular surface, supported by the observed cellular hyperplasia. The redox imbalance and the inflammatory response modulated by IL-10 play a key role in the response triggered by air pollutants on the cornea. Taking into account this time course study, the ocular surface should also be considered as a relevant target of urban air pollutants.
Assuntos
Poluentes Atmosféricos/toxicidade , Poluição do Ar/efeitos adversos , Epitélio Corneano/patologia , Animais , Brasil , Cidades , Epitélio Corneano/efeitos dos fármacos , Hiperplasia/induzido quimicamente , Hiperplasia/patologia , Interleucina-10/metabolismo , Masculino , Camundongos , NADPH Oxidase 4/metabolismo , Oxirredução/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Fatores de Tempo , Testes de Toxicidade Subaguda , Testes de Toxicidade SubcrônicaRESUMO
PURPOSE: The aim of this study was to evaluate oxidative stress markers in human conjunctival epithelial cells (IOBA-NHC) exposed to diesel exhaust particles (DEP). METHODS: Reactive oxygen (ROS) and nitrogen (RNS) species production; hydrogen peroxide (H2O2) levels; protein oxidation; antioxidant enzymes activities (superoxide dismutase [SOD], catalase [CAT], glutathione peroxidase [GPx], glutathione S-transferase [GST], and glutathione reductase [GR]); total reactive antioxidant potential (TRAP); reduced (GSH) and oxidized glutathione (GSSG) were evaluated. Transmission electron microscopy was performed to evaluate DEP uptake. RESULTS: Diesel exhaust particles were entrapped by membrane protrusions developed by IOBA-NHC. Cells exposed to DEP 50 and 100 µg/mL showed a significant increase in ROS, RNS, H2O2 levels, SOD, GPx, and GST compared with the control group. A significant decay in GR was observed in both groups, meanwhile CAT levels remained unchanged. The group exposed to DEP 100 µg/mL displayed a significant increase in protein oxidation. In both groups, TRAP was significantly reduced as well as the GSH/GSSG ratio. CONCLUSIONS: The decrease in nonenzymatic antioxidants and the compensatory increase of SOD, GPX, and GST activities are consequence of the increase in ROS and RNS production due to DEP exposure and its accumulation inside the cells. The decay in GR activity leads to the decrease in GSH/GSSG recycling. These results suggest that oxidative stress could play an important role in the development of DEP effects on human conjunctival epithelial cells.
Assuntos
Túnica Conjuntiva/metabolismo , Células Epiteliais/metabolismo , Estresse Oxidativo/fisiologia , Espécies Reativas de Oxigênio/metabolismo , Emissões de Veículos , Biomarcadores/metabolismo , Células Cultivadas , Túnica Conjuntiva/efeitos dos fármacos , Túnica Conjuntiva/ultraestrutura , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/ultraestrutura , Humanos , Microscopia Eletrônica de TransmissãoRESUMO
In a normal diet, the use of herbs may contribute significantly to the total intake of plant antioxidants and even be a better source of dietary antioxidants than many other food groups. Therefore, the aims of this study were to evaluate the protective effect of aqueous extracts of Aloysia triphylla (infusion and decoction) against lipid-peroxidation of brain homogenates and to determine changes in the prooxidant/antioxidant balance when the plant material is added. In order to elucidate a possible antioxidant mechanism in vitro evaluation of total antioxidant capacity, oxygen species scavenging ability and reducing power (RP) were studied. Tested extracts had shown a strong inhibition of lipid-peroxidation measured as thiobarbituric acid-reactive products of lipid-peroxidation (TBARS) and chemiluminescence. Furthermore, infusion and decoction exhibited free radical trapping ability, expressed by the capacity to scavenge superoxide and hydrogen peroxide. Additionally, both aqueous extracts presented antioxidant activity measured as total reactive antioxidant potential (TRAP), 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and 2,2'-azino-bis(3-ethylbenzthiazoline)-6-sulfonic acid radical (ABTS) scavenging activity and RP. These results suggest that the lipid-peroxidation inhibition mechanism proposed is that the antioxidants present in Aloysia triphylla could act as strong scavengers of reactive oxygen species not only at the initiation of the lipid-peroxidation chain reaction, but also at the propagation step. Therefore, they could be used as prophylactic and therapeutic agents for those diseases where the occurrence of oxidative stress and lipid-peroxidation contributes to the progression of damage.
Assuntos
Antioxidantes/farmacologia , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Extratos Vegetais/farmacologia , Verbenaceae/química , Animais , Feminino , Peroxidação de Lipídeos/efeitos dos fármacos , Camundongos , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismoRESUMO
PURPOSE: The goal of the present study is to establish the antioxidant status in the brain of a high pressure-induced rat model. METHODS: Ocular hypertension was induced in rats (n = 12) cauterizing two episcleral veins under a surgical microscope. A sham procedure (n = 12) was performed in the control group. The markers evaluated in the brain 7 days after surgery were as follows: spontaneous chemiluminescence, protein carbonylation, nitrite concentration, total reactive antioxidant potential (TRAP), ascorbic acid, glutathione, vitamin E and activities of superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase. RESULTS: Chemiluminescence in glaucoma was 55% higher than in controls (393 ± 20 cpm/mg protein, p < 0.001). Protein carbonylation in glaucoma was 93% higher than in controls (1.15 ± 0.18 nmol/mg protein, p < 0.001). Nitrite concentration was 5.30 ± 0.25 µM for glaucoma (controls 4.41 ± 0.24 µM, p < 0.05). Total reactive antioxidant potential decreased by 42% in glaucoma (controls 153 ± 14 µM Trolox, p < 0.001). Ascorbic acid was 67 ± 26 µM for glaucoma (controls 275 ± 22 µM, p < 0.001). Vitamin E was 0.58 ± 0.05 µmol/g organ for glaucoma (controls 1.10 ± 0.06 µmol/g organ, p < 0.01). Glutathione was 1.98 ± 0.13 µmol/g organ for glaucoma (controls 8.19 ± 0.71 µmol/g organ, p < 0.001). Superoxide dismutase and GPx were increased in glaucoma by 42 and 59%, respectively (p < 0.05). CONCLUSIONS: Reactive oxygen and nitrogen species were increased in glaucoma, the increase in chemiluminescence, protein carbonylation and nitrite levels could be evidenced by this situation. The decrease in nonenzymatic antioxidants and a compensatory increase in SOD and GPx activity may have been a consequence of an increase in oxidative processes.
Assuntos
Antioxidantes/metabolismo , Encéfalo/metabolismo , Modelos Animais de Doenças , Pressão Intraocular , Hipertensão Ocular/metabolismo , Estresse Oxidativo , Animais , Ácido Ascórbico/metabolismo , Catalase/metabolismo , Feminino , Glutationa/metabolismo , Glutationa Peroxidase/metabolismo , Luminescência , Carbonilação Proteica , Ratos , Ratos Wistar , Espécies Reativas de Nitrogênio/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Superóxido Dismutase/metabolismo , Vitamina E/metabolismoRESUMO
The aim of the present work was to make a contribution to the knowledge of aqueous extracts of Lippia turbinata and Aloysia citriodora (Verbenaceae; infusion and decoction) in relation with the establishment of its antioxidant activity and lack of DNA damage, for its potential use in therapeutics. The cytogenotoxic profile was evaluated through genotoxic biomarkers such as mitotic index, cellular proliferation kinetics, sister chromatid exchanges, single-cell gel electrophoresis assay, and micronucleus test in human peripheral blood lymphocyte cultures. No statistical differences were found (P > .05) between control and exposed cultures, even between both aqueous extracts. The total antioxidant capacity was shown to be higher in the decoction than in the infusion and both aqueous extracts protected against protein carbonylation and lipid peroxidation, the decoction being more efficient than the infusion (P < .005). These results suggest the safe use of these medicinal plants as chemoecologic agents in therapeutics.
Assuntos
Antioxidantes/farmacologia , Extratos Vegetais/farmacologia , Verbenaceae , Animais , Encéfalo/metabolismo , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Ensaio Cometa , Dano ao DNA , Feminino , Flavonoides/análise , Humanos , Medições Luminescentes , Linfócitos , Testes para Micronúcleos , Índice Mitótico , Componentes Aéreos da Planta/química , Plantas Medicinais/química , Polifenóis/análise , Ratos , Ratos Wistar , Troca de Cromátide Irmã/efeitos dos fármacos , Taninos/análise , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismo , Verbenaceae/químicaRESUMO
PURPOSE: To evaluate the relationship between oxidative stress markers and increased intraocular pressure in experimental glaucoma. METHODS: In vivo chemiluminescence (CL), total antioxidant capacity (TRAP), nitrite concentration (NC), and lipid peroxidation markers (TBARS) were evaluated. Wistar rats (n=18 for each time point) underwent operation, and two episcleral veins were cauterized. RESULTS: Decreases of 22%, 35%, and 27% at 7, 15, and 30 days and an increase of 22% at 60 days in CL were observed in glaucomatous eyes. In optic nerve, TBARS values were 6.9+/-0.5 nmol/mg protein (7 days), 9.4+/-0.4 nmol/mg protein (15 days), 18.0+/-1.2 nmol/mg protein (30 days), and 43.1+/-5.3 nmol/mg protein (60 days) (control, 6.2+/-0.4 nmol/mg protein; P<0.001). NC was 37.0+/-1.8 microM (7 days), 31.4+/-1.2 microM (15 days), 39.6+/-1.3 microM (30 days), and 40.0+/-1.3 microM (60 days) (control, 21.1+/-1.7 microM; P<0.001). In glaucomatous vitreous humor, TRAP decreased by 42% at 15 days and 78% at 60 days (control, 414+/-29 microM; P<0.001). In glaucomatous aqueous humor, TRAP values were 75+/-7 microM (7 days), 54+/-4 microM (15 days), 25+/-4 microM (30 days), and 50+/-3 microM (60 days) (control, 90+/-10 microM; P<0.001). CONCLUSIONS: Reactive species were increased in glaucoma, as evidenced by the increases in CL, TBARS, and NC. The decrease in the antioxidant levels may be a consequence of an increase in oxidative processes.