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1.
Braz. j. med. biol. res ; 51(10): e7439, 2018. graf
Article in English | LILACS | ID: biblio-951707

ABSTRACT

Nuclear factor erythroid-related factor 2 (Nrf2) has been implicated in several detoxifying and antioxidant defense processes. Nrf2-mediated heme oxygenase-1 (HO-1) expression was demonstrated to play a key role against oxidative stress. Gastrodin (GSTD) is a well-known active compound isolated from the roots of Rhizoma gastrodiae, a plant used in ancient Chinese traditional medicine. The aim of this work was to investigate whether GSTD could alleviate H2O2-induced oxidative stress in mouse liver sinusoidal endothelial cells (LSECs). In LSECs exposed to 1 mM H2O2, treatment with GSTD (1, 10, or 50 µM) resulted in higher cell viability than the untreated control. Treated cells maintained a higher Bcl2/Bax ratio and suppressed caspase-9 expression compared with untreated cells, reducing cell apoptosis. GSTD was protective for H2O2-induced oxidative injury by reducing the generation of intracellular reactive oxygen species and malondialdehyde. HO-1 and Nrf2 expressions were synergistically upregulated by GSTD. Inhibition of HO-1 by 10 µM zinc protoporphyrin resulted in less protective effects on cell viability and malondialdehyde reduction by GSTD treatment in H2O2-exposed LSECs. Additionally, phosphorylated p38 in LSECs exposed to H2O2 was elevated by GSTD. Inhibition of p38 phosphorylation by SB203580 did not induce Nrf2 and HO-1 expression after 1 or 10 µM GSTD treatment and the protective effect on cell viability and malondialdehyde reduction in H2O2-exposed LSECs was reduced. The data conclusively demonstrated that GSTD-induced HO-1 and Nrf2 expression is involved in protection of LSECs from H2O2-induced oxidative injury, which may be regulated by p38 phosphorylation.


Subject(s)
Animals , Rabbits , Benzyl Alcohols/pharmacology , Endothelial Cells/drug effects , p38 Mitogen-Activated Protein Kinases/metabolism , Heme Oxygenase-1/metabolism , Glucosides/pharmacology , Hydrogen Peroxide/pharmacology , Up-Regulation/drug effects , Cell Survival/drug effects , Apoptosis/drug effects , Liver/cytology , Liver/drug effects , Malondialdehyde/metabolism , Models, Theoretical
2.
Biol. Res ; 51: 17, 2018. graf
Article in English | LILACS | ID: biblio-950903

ABSTRACT

BACKGROUND: Improper control on reactive oxygen species (ROS) elimination process and formation of free radicals causes tissue dysfunction. Pineal hormone melatonin is considered a potent regulator of such oxidative damage in different vertebrates. Aim of the current communication is to evaluate the levels of oxidative stress and ROS induced damage, and amelioration of oxidative status through melatonin induced activation of signaling pathways. Hepatocytes were isolated from adult Labeo rohita and exposed to H2O2 at three different doses (12.5, 25 and 50 µM) to observe peroxide induced damage in fish hepatocytes. Melatonin (25, 50 and 100 µg/ml) was administered against the highest dose of H2O2. Enzymatic and non-enzymatic antioxidants such as malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH) was measured spectrophotometrically. Expression level of heat shock proteins (HSP70 and HSP90), HSPs-associated signaling molecules (Akt, ERK, cytosolic and nuclear NFkB), and melatonin receptor was also measured by western blotting analysis. RESULTS: H2O2 induced oxidative stress significantly altered (P < 0.05) MDA and GSH level, SOD and CAT activity, and up regulated HSP70 and HSP90 expression in carp hepatocytes. Signaling proteins exhibited differential modulation as revealed from their expression patterns in H2O2-exposed fish hepatocytes, in comparison with control hepatocytes. Melatonin treatment of H2O2-stressed fish hepatocytes restored basal cellular oxidative status in a dose dependent manner. Melatonin was observed to be inducer of signaling process by modulation of signaling molecules and melatonin receptor. CONCLUSIONS: The results suggest that exogenous melatonin at the concentration of 100 µg/ml is required to improve oxidative status of the H2O2-stressed fish hepatocytes. In H2O2 exposed hepatocytes, melatonin modulates expression of HSP70 and HSP90 that enable the hepatocytes to become stress tolerant and survive by altering the actions of ERK, Akt, cytosolic and nuclear NFkB in the signal transduction pathways. Study also confirms that melatonin could act through melatonin receptor coupled to ERK/Akt signaling pathways. This understanding of the mechanism by which melatonin regulates oxidative status in the stressed hepatocytes may initiate the development of novel strategies for hepatic disease therapy in future.


Subject(s)
Animals , Signal Transduction/drug effects , Oxidative Stress/drug effects , Hepatocytes/drug effects , Hydrogen Peroxide/pharmacology , Melatonin/pharmacology , Spectrophotometry , Superoxide Dismutase/drug effects , Catalase/drug effects , Catalase/metabolism , Blotting, Western , NF-kappa B/drug effects , NF-kappa B/metabolism , Reactive Oxygen Species/metabolism , MAP Kinase Signaling System/drug effects , Hepatocytes/metabolism , Proto-Oncogene Proteins c-akt/drug effects , Fishes , Glutathione/drug effects , Glutathione/metabolism , Malondialdehyde/metabolism
3.
Indian J Biochem Biophys ; 2014 Dec ; 51 (6): 552-558
Article in English | IMSEAR | ID: sea-156536

ABSTRACT

Ultraviolet C (UVC) irradiation (λ: 200-280 nm) causes release of several secretory cytokines responsible for inflammation. Our objective was to investigate whether inflammatory response was also induced in bystander cells. For this purpose, the conditioned medium containing the released factors from UVC irradiated A375 cells was used in this study to evaluate the expression of inflammatory markers, such as tumour necrosis factor alpha (TNFα), nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) and p38 mitogen-activated protein kinase (p38 MAPK) in its bystander cells. Inflammatory responses in bystander cells subjected to further irradiation by UVC or other damaging agent like H2O2 were also examined. It was observed that TNFα, NFκB and p38 MAPK were not induced in UVC-bystander cells, but their expression was suppressed in the UVC-bystander cells treated with UVC or H2O2. This lowering in inflammatory response might be due to smaller depletion in the reduced glutathione (GSH) content present in these treated bystander cells. The study indicated that UVC-induced bystander effect was an intrinsic protective response in cells, capable of suppressing inflammation induced in cells on exposure to damaging agents.


Subject(s)
Bystander Effect/drug effects , Bystander Effect/immunology , Bystander Effect/radiation effects , Cell Line, Tumor , Cytokines/immunology , Humans , Hydrogen Peroxide/pharmacology , Inflammation/immunology , /immunology , Radiation Dosage , Ultraviolet Rays
4.
Article in English | WPRIM | ID: wpr-24553

ABSTRACT

Chronic enteritis can produce an excess of reactive oxygen species resulting in cellular damage. Stanniocalcin-1(STC-1) reportedly possesses anti-oxidative activity, the aim of this study was to define more clearly the direct contribution of STC-1 to anti-oxidative stress in cattle. In this study, primary intestinal epithelial cells (IECs) were exposed to hydrogen peroxide (H2O2) for different time intervals to mimic chronic enteritis-induced cellular damage. Prior to treatment with 200 microM H2O2, the cells were transfected with a recombinant plasmid for 48 h to over-express STC-1. Acridine orange/ethidium bromide (AO/EB) double staining and trypan blue exclusion assays were then performed to measure cell viability and apoptosis of the cells, respectively. The expression of STC-1 and apoptosis-related proteins in the cells was monitored by real-time PCR and Western blotting. The results indicated that both STC-1 mRNA and protein expression levels positively correlated with the duration of H2O2 treatment. H2O2 damaged the bovine IECs in a time-dependent manner, and this effect was attenuated by STC-1 over-expression. Furthermore, over-expression of STC-1 up-regulated Bcl-2 protein expression and slightly down-regulated caspase-3 production in the damaged cells. Findings from this study suggested that STC-1 plays a protective role in intestinal cells through an antioxidant mechanism.


Subject(s)
Animals , Animals, Newborn , Blotting, Western/veterinary , Caspase 3/genetics , Cattle , Cattle Diseases/etiology , Duodenum/metabolism , Enteritis/etiology , Epithelial Cells/metabolism , Gene Expression Regulation , Glycoproteins/genetics , Hydrogen Peroxide/pharmacology , Male , Proto-Oncogene Proteins c-bcl-2/genetics , RNA, Messenger/genetics , Real-Time Polymerase Chain Reaction/veterinary
5.
Yonsei Medical Journal ; : 1152-1156, 2014.
Article in English | WPRIM | ID: wpr-207145

ABSTRACT

Pasteurella multocida (P. multocida) infections vary widely, from local infections resulting from animal bites and scratches to general infections. As of yet, no vaccine against P. multocida has been developed, and the most effective way to prevent pathogenic transmission is to clean the host environment using disinfectants. In this study, we identified which disinfectants most effectively inhibited environmental isolates of P. multocida. Three readily available disinfectants were compared: 3% hydrogen peroxide (HP), 70% isopropyl alcohol, and synthetic phenol. In suspension tests and zone inhibition tests, 3% HP was the most promising disinfectant against P. multocida.


Subject(s)
Disinfectants/pharmacology , Hydrogen Peroxide/pharmacology , Microbial Sensitivity Tests , Pasteurella multocida/drug effects
6.
Biol. Res ; 47: 1-11, 2014. graf, tab
Article in English | LILACS | ID: biblio-950746

ABSTRACT

BACKGROUND: Accumulating evidence indicates that reactive oxygen species (ROS) are an important etiological factor for the induction of dermal papilla cell senescence and hair loss, which is also known alopecia. Arctiin is an active lignin isolated from Arctium lappa and has anti-inflammation, anti-microbial, and anti-carcinogenic effects. In the present study, we found that arctiin exerts anti-oxidative effects on human hair dermal papilla cells (HHDPCs). RESULTS: To better understand the mechanism, we analyzed the level of hydrogen peroxide (H2O2)-induced cytotoxicity, cell death, ROS production and senescence after arctiin pretreatment of HHDPCs. The results showed that arctiin pretreatment significantly inhibited the H2O2-induced reduction in cell viability. Moreover, H2O2-induced sub-G1 phase accumulation and G2 cell cycle arrest were also downregulated by arctiin pretreatment. Interestingly, the increase in intracellular ROS mediated by H2O2 was drastically decreased in HHDPCs cultured in the presence of arctiin. This effect was confirmed by senescence associated-beta galactosidase (SA-ß-gal) assay results; we found that arctiin pretreatment impaired H2O2-induced senescence in HHDPCs. Using microRNA (miRNA) microarray and bioinformatic analysis, we showed that this anti-oxidative effect of arctiin in HHDPCs was related with mitogen-activated protein kinase (MAPK) and Wnt signaling pathways. CONCLUSIONS: Taken together, our data suggest that arctiin has a protective effect on ROS-induced cell dysfunction in HHDPCs and may therefore be useful for alopecia prevention and treatment strategies.


Subject(s)
Humans , Aging/metabolism , Reactive Oxygen Species/antagonists & inhibitors , Hair Follicle/drug effects , MicroRNAs/metabolism , Furans/pharmacology , Glucosides/pharmacology , Aging/drug effects , Down-Regulation/drug effects , Up-Regulation/drug effects , Cell Line , Cell Survival/drug effects , Cell Death/drug effects , beta-Galactosidase/analysis , Hair Follicle/cytology , Hair Follicle/metabolism , Dermis/cytology , Dermis/drug effects , Dermis/metabolism , Oligonucleotide Array Sequence Analysis , MicroRNAs/drug effects , Cell Cycle Checkpoints/drug effects , Hydrogen Peroxide/pharmacology
7.
Braz. j. med. biol. res ; 46(9): 746-751, 19/set. 2013. graf
Article in English | LILACS | ID: lil-686569

ABSTRACT

Macrophage migration inhibitory factor (MIF), a pleiotropic cytokine, plays an important role in the pathogenesis of atrial fibrillation; however, the upstream regulation of MIF in atrial myocytes remains unclear. In the present study, we investigated whether and how MIF is regulated in response to the renin-angiotensin system and oxidative stress in atrium myocytes (HL-1 cells). MIF protein and mRNA levels in HL-1 cells were assayed using immunofluorescence, real-time PCR, and Western blot. The result indicated that MIF was expressed in the cytoplasm of HL-1 cells. Hydrogen peroxide (H2O2), but not angiotensin II, stimulated MIF expression in HL-1 cells. H2O2-induced MIF protein and gene levels increased in a dose-dependent manner and were completely abolished in the presence of catalase. H2O2-induced MIF production was completely inhibited by tyrosine kinase inhibitors genistein and PP1, as well as by protein kinase C (PKC) inhibitor GF109203X, suggesting that redox-sensitive MIF production is mediated through tyrosine kinase and PKC-dependent mechanisms in HL-1 cells. These results suggest that MIF is upregulated by HL-1 cells in response to redox stress, probably by the activation of Src and PKC.


Subject(s)
Animals , Mice , Hydrogen Peroxide/pharmacology , Intramolecular Oxidoreductases/drug effects , Macrophage Migration-Inhibitory Factors/drug effects , Myocytes, Cardiac/metabolism , Oxidants/pharmacology , Protein Kinase C/metabolism , src-Family Kinases/metabolism , Angiotensin II/metabolism , Blotting, Western , Cell Line , Immunohistochemistry , Intramolecular Oxidoreductases/genetics , Microscopy, Confocal , Macrophage Migration-Inhibitory Factors/genetics , Oxidative Stress/physiology , Protein Kinase Inhibitors/pharmacology , Real-Time Polymerase Chain Reaction , Renin-Angiotensin System/physiology
8.
Biocell ; 37(1): 1-9, Apr. 2013. ilus, graf
Article in English | LILACS | ID: lil-694715

ABSTRACT

Cell lines with high passage numbers exhibit alterations in cell morphology and functions. In the present work, C2C12 skeletal muscle cells with either low (<20) or high (>60) passage numbers (identified as l-C2C12 or h-C2C12, respectively) were used to investigate the apoptotic response to H2O2 as a function of culture age h-C2C12. We found that older cultures (h-C2C12 group) were depleted of mitochondrial DNA (mtDNA). When we analyzed the behavior of Bad, Bax, caspase-3 and mitochondrial transmembrane potential, we observed that cells in the h-C2C12 group were resistant to H2O2 induction of apoptosis. We propose serially cultured C2C12 cells as a refractory model to H2O2-induced apoptosis. In addition, the data obtained in this work suggest that mtDNA is required for apoptotic cell death in skeletal muscle C2C12 cells.


Subject(s)
Animals , Mice , Apoptosis/drug effects , Hydrogen Peroxide/pharmacology , Mitochondria/pathology , Myoblasts, Skeletal/pathology , Oxidants/pharmacology , Blotting, Western , Cell Culture Techniques , Cells, Cultured , /metabolism , Cell Division/drug effects , Immunoprecipitation , Microscopy, Fluorescence , Membrane Potential, Mitochondrial/drug effects , Mitochondria/drug effects , Mitochondria/metabolism , Myoblasts, Skeletal/drug effects , Myoblasts, Skeletal/metabolism , /metabolism
9.
Rev. Soc. Bras. Med. Trop ; 45(5): 620-626, Sept.-Oct. 2012. ilus
Article in English | LILACS | ID: lil-656219

ABSTRACT

INTRODUCTION: The capacity to overcome the oxidative stress imposed by phagocytes seems to be critical for Candida species to cause invasive candidiasis. METHODS: To better characterize the oxidative stress response (OSR) of 8 clinically relevant Candida sp., glutathione, a vital component of the intracellular redox balance, was measured using the 5,5'-dithiobis-(2-nitrobenzoic acid (DTNB)-glutathione disulfide (GSSG) reductase reconversion method; the total antioxidant capacity (TAC) was measured using a modified method based on the decolorization of the 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic) acid radical cation (ABTS*+). Both methods were used with cellular Candida sp. extracts treated or not with hydrogen peroxide (0.5 mM). RESULTS: Oxidative stress induced by hydrogen peroxide clearly reduced intracellular glutathione levels. This depletion was stronger in Candida albicans and the levels of glutathione in untreated cells were also higher in this species. The TAC demonstrated intra-specific variation. CONCLUSIONS: Glutathione levels did not correlate with the measured TAC values, despite this being the most important non-enzymatic intracellular antioxidant molecule. The results indicate that the isolated measurement of TAC does not give a clear picture of the ability of a given Candida sp. to respond to oxidative stress.


INTRODUÇÃO: A capacidade de suportar o estresse oxidativo imposto por fagócitos parece ser crítica para que espécies de Candida causem candidíase invasiva. MÉTODOS: Para melhor caracterizar a resposta ao estresse oxidativo (REO) de oito Candida sp. clinicamente relevantes, um componente vital do balanço redox intracelular, a glutationa, foi mensurada pelo método de reconversão DTNB-GSSG redutase e a capacidade antioxidante total (CAT) foi mensurada por um método modificado baseado na descoloração do ABTS*+. Ambos os métodos foram utilizados em extratos celulares das espécies de Candida tratadas ou não com peróxido de hidrogênio (0,5mM). RESULTADOS: O estresse oxidativo induzido pelo peróxido de hidrogênio claramente reduziu os níveis intracelulares de glutationa. Esta diminuição foi mais intensa em C. albicans e os níveis de glutationa em células não tratadas foram também maiores nesta espécie. A capacidade antioxidante total demonstrou variação intraespecífica na capacidade antioxidante. CONCLUSÕES: Os níveis de glutationa não se correlacionaram com a capacidade antioxidante total mensurada, apesar desta ser a defesa antioxidante intracelular não-enzimática mais importante. Os resultados indicam que a medição isolada da CAT não fornece um quadro claro da habilidade de certa espécie de Candida responder ao estresse oxidativo.


Subject(s)
Antioxidants/pharmacology , Candida/drug effects , Candidiasis/microbiology , Glutathione/analysis , Hydrogen Peroxide/pharmacology , Oxidative Stress/drug effects , Candida/metabolism , Candida/pathogenicity , Dithionitrobenzoic Acid/analysis , Oxidation-Reduction , Oxidants/pharmacology , Sulfhydryl Reagents/analysis , Virulence
10.
Mem. Inst. Oswaldo Cruz ; 107(4): 494-502, June 2012. ilus
Article in English | LILACS | ID: lil-626443

ABSTRACT

Ascorbate peroxidases (APX) are class I heme-containing enzymes that convert hydrogen peroxide into water molecules. The gene encoding APX has been characterized in 11 strains of Trypanosoma cruzi that are sensitive or resistant to benznidazole (BZ). Bioinformatic analysis revealed the presence of two complete copies of the T. cruzi APX (TcAPX) gene in the genome of the parasite, while karyotype analysis showed that the gene was present in the 2.000-kb chromosome of all of the strains analyzed. The sequence of TcAPX exhibited greater levels of similarity to those of orthologous enzymes from Leishmania spp than to APXs from the higher plant Arabidopsis thaliana. Northern blot and real-time reverse transcriptase polymerase chain reaction (RT-PCR) analyses revealed no significant differences in TcAPX mRNA levels between the T. cruzi strains analyzed. On the other hand, Western blots showed that the expression levels of TcAPX protein were, respectively, two and three-fold higher in T. cruzi populations with in vitro induced (17 LER) and in vivo selected (BZR) resistance to BZ, in comparison with their corresponding susceptible counterparts. Moreover, the two BZ-resistant populations exhibited higher tolerances to exogenous hydrogen peroxide than their susceptible counterparts and showed TcAPX levels that increased in a dose-dependent manner following exposure to 100 and 200 µM hydrogen peroxide.


Subject(s)
Ascorbate Peroxidases/analysis , Drug Resistance/genetics , Hydrogen Peroxide/pharmacology , Nitroimidazoles/pharmacology , Trypanocidal Agents/pharmacology , Trypanosoma cruzi/enzymology , Ascorbate Peroxidases/genetics , Blotting, Western , DNA, Protozoan/analysis , Electrophoresis, Gel, Pulsed-Field , Molecular Sequence Data , Phylogeny , Reverse Transcriptase Polymerase Chain Reaction , RNA, Messenger/genetics , Sequence Analysis, DNA , Trypanosoma cruzi/drug effects
11.
Braz. j. med. biol. res ; 45(6): 473-481, June 2012. ilus, tab
Article in English | LILACS | ID: lil-622783

ABSTRACT

Electron paramagnetic resonance (EPR) spectroscopy of spin labels was used to monitor membrane dynamic changes in erythrocytes subjected to oxidative stress with hydrogen peroxide (H2O2). The lipid spin label, 5-doxyl stearic acid, responded to dramatic reductions in membrane fluidity, which was correlated with increases in the protein content of the membrane. Membrane rigidity, associated with the binding of hemoglobin (Hb) to the erythrocyte membrane, was also indicated by a spin-labeled maleimide, 5-MSL, covalently bound to the sulfhydryl groups of membrane proteins. At 2% hematocrit, these alterations in membrane occurred at very low concentrations of H2O2 (50 µM) after only 5 min of incubation at 37°C in azide phosphate buffer, pH 7.4. Lipid peroxidation, suggested by oxidative hemolysis and malondialdehyde formation, started at 300 µM H2O2 (for incubation of 3 h), which is a concentration about six times higher than those detected with the probes. Ascorbic acid and α-tocopherol protected the membrane against lipoperoxidation, but did not prevent the binding of proteins to the erythrocyte membrane. Moreover, the antioxidant (+)-catechin, which also failed to prevent the cross-linking of cytoskeletal proteins with Hb, was very effective in protecting erythrocyte ghosts from lipid peroxidation induced by the Fenton reaction. This study also showed that EPR spectroscopy can be useful to assess the molecular dynamics of red blood cell membranes in both the lipid and protein domains and examine oxidation processes in a system that is so vulnerable to oxidation.


Subject(s)
Humans , Antioxidants/pharmacology , Erythrocyte Membrane/drug effects , Hydrogen Peroxide/pharmacology , Lipid Peroxidation/drug effects , Membrane Proteins/metabolism , Thiobarbituric Acid Reactive Substances/metabolism , Ascorbic Acid/pharmacology , Catechin/pharmacology , Cyclic N-Oxides/metabolism , Electron Spin Resonance Spectroscopy , Erythrocyte Membrane/chemistry , Erythrocyte Membrane/physiology , Hemolysis , Hydrogen-Ion Concentration , Hemoglobins/metabolism , Hydrogen Peroxide/metabolism , Membrane Fluidity/drug effects , Oxidative Stress/physiology , alpha-Tocopherol/pharmacology
12.
Braz. oral res ; 26(3): 269-274, May-June 2012. tab
Article in English | LILACS | ID: lil-622944

ABSTRACT

The aim of this study was to evaluate the bleaching effect of two mouth rinses containing hydrogen peroxide. Thirty premolars were randomly divided into two groups (n = 15): Listerine Whitening (LW) and Colgate Plax Whitening (PW). The teeth were fixed on a wax plate and with acrylic resin, at a distance of 5 mm between each other, exposing the buccal surfaces. All teeth were stored in artificial saliva for 45 days, being removed twice a day to be immersed for 1 min in each mouthwash, followed by 10-second washing in tap water. The pH of each product was measured. Digital images of each tooth were captured under standardized conditions. These images were cut in areas previously demarcated and analyzed in Adobe Photoshop 7.0 using the CIEL*a*b* color space system. Data were statistically analyzed by a paired t test and an independent samples t test (p < 0.05). The pH values were 5.6 and 3.4 for LW and PW, respectively. Both treatment groups showed a decrease in the b* parameter (p < 0.01), but a decrease of a* was observed only for PW (p < 0.01). While the LW group showed an improvement in lightness (L*) (p = 0.03), the PW group had a decrease in the L* parameter (p = 0.02). Within the limitations of this study, it is possible to conclude that both products caused some degree of whitening; however, extreme care should be taken when using Colgate Plax Whitening, since its decline in luminosity might be due to its lower pH.


Subject(s)
Humans , Hydrogen Peroxide/pharmacology , Mouthwashes/pharmacology , Tooth Bleaching Agents/pharmacology , Tooth Bleaching/methods , Color , Hydrogen Peroxide/chemistry , Mouthwashes/chemistry , Random Allocation , Reproducibility of Results , Saliva, Artificial , Time Factors , Tooth Bleaching Agents/chemistry , Tooth Discoloration/therapy
13.
Braz. dent. j ; 23(2): 110-115, Mar.-Apr. 2012. ilus, tab
Article in English | LILACS | ID: lil-626297

ABSTRACT

The aim of this study was to evaluate effect of bleaching agents on sound enamel (SE) and enamel with early artificial caries lesions (CL) using confocal laser scanning microscopy (CLSM). Eighty blocks (4 x 5 x 5 mm) of bovine enamel were used and half of them were submitted to a pH cycling model to induce CL. Eight experimental groups were obtained from the treatments and mineralization level of the enamel (SE or CL) (n=10). SE groups: G1 - unbleached (control); G2 - 4% hydrogen peroxide (4 HP); G3 - 4 HP containing 0.05% Ca (Ca); G4 - 7.5% hydrogen peroxide (7.5 HP) containing amorphous calcium phosphate (ACP). CL groups: G5 - unbleached; G6 - 4 HP; G7 - 4 HP containing Ca; G8 - 7.5 HP ACP. G2, G3, G6, G7 were treated with the bleaching agents for 8 h/day during 14 days, while G4 and G8 were exposed to the bleaching agents for 30 min twice a day during 14 days. The enamel blocks were stained with 0.1 mM rhodamine B solution and the demineralization was quantified using fluorescence intensity detected by CLSM. Data were analyzed using ANOVA and Fisher’s tests (α=0.05). For the SE groups, the bleaching treatments increased significantly the demineralization area when compared with the unbleached group. In the CL groups, no statistically significant difference was observed (p>0.05).The addition of ACP or Ca in the composition of the whitening products did not overcome the effects caused by bleaching treatments on SE and neither was able to promote remineralization of CL.


O objetivo deste estudo foi avaliar o efeito de agentes clareadores no esmalte sadio (ES) ou esmalte com lesão inicial de cárie artificial (LC), utilizando microscopia confocal laser de varredura (CLSM). Oitenta blocos (4 x 5 x 5 mm) de esmalte bovino foram usados, sendo que 40 destes foram desmineralizados com ciclagem de pH para induzir a LC. Oito grupos experimentais foram obtidos a partir dos tratamentos e condição do esmalte (ES ou LC), com n=10: Grupos ES: G1 - sem tratamento (controle); G2 - peróxido de hidrogênio 4% (PH4); G3: PH4 contendo 0,05% cálcio (Ca); G4 - peróxido de hidrogênio 7,5% (pH 7,5) contendo fosfato de cálcio amorfo (ACP). Grupos LC: G5 - não clareado; G6 - pH 4; G7 - pH 4 Ca; G8 - pH 7,5 ACP. Os grupos G2, G3, G6 e G7 foram tratados com o gel clareador por 8 h/dia durante 14 dias, enquanto as amostras dos grupos G4 e G8 foram submetidas ao agente clareador por 30 min/duas vezes ao dia, durante 14 dias. Os blocos de esmalte foram corados com solução de Rodamina B e a área fluorescente de desmineralização foi quantificada utilizando CLSM. Os dados foram submetidos a ANOVA e teste de Fisher (p<0,05). Para ES, os tratamentos clareadores aumentaram significativamente a área de desmineralização quando comparado com os grupos não clareados, entretanto, para LC não foi observado diferença estatística significante entre os grupos. A adição de ACP e Ca na composição dos géis clareadores não anulou os efeitos dos tratamentos clareadores no ES, assim como não teve capacidade de remineralizar o LC.


Subject(s)
Animals , Cattle , Calcium Phosphates/pharmacology , Dental Caries/chemically induced , Dental Enamel/drug effects , Hydrogen Peroxide/pharmacology , Tooth Remineralization , Tooth Bleaching Agents/adverse effects , Tooth Demineralization/chemically induced , Analysis of Variance , Dental Caries/physiopathology , Hardness , Microscopy, Confocal/methods , Tooth Bleaching/adverse effects
14.
Article in English | WPRIM | ID: wpr-192551

ABSTRACT

During ischemia-reperfusion injury, brief pre-exposure to oxidative stress renders organs resistant to subsequent severe damage. NF-kappaB is a transcription factor that is involved in reperfusion-induced inflammatory and immune responses. The activity of NF-kappaB has been shown to be modulated by oxidative stress in various cell types through different pathways. We studied the effect of pre-exposure to oxidative stress on subsequent NF-kappaB activation in TNFalpha-stimulated HEK293 cells. The cells were transiently exposed to 0.5 mM H2O2 for 20 min, prior to stimulation with TNFalpha, and the subsequent expression of NF-kappaB-dependent genes and the levels of NF-kappaB signaling molecules were measured. Pre-exposure to H2O2 significantly delayed the TNFalpha-induced expression of an NF-kappaB reporter gene and inflammatory proteins (intercellular adhesion molecule-1 and IL-1beta). The degradation of inhibitor of NF-kappaB alpha (IkappaBalpha) and the nuclear translocation of NF-kappaB were also delayed by H2O2 treatment, whereas IkappaBalpha phosphorylation and IkappaB kinase activity were not changed. When we examined the ubiquitin/proteosome pathway in H2O2-treated cells, we could not detect significant changes in proteosomal peptidase activities, but we were able to detect a delay of IkappaBalpha poly-ubiquitination. Our results suggest that transient exposure to oxidative stress temporally inhibits NF-kappaB-dependent gene expression by suppressing the poly-ubiquitination of phosphorylated IkappaBalpha in HEK293 cells.


Subject(s)
Active Transport, Cell Nucleus , Cell Nucleus/metabolism , Enzyme Activation/drug effects , HEK293 Cells , Humans , Hydrogen Peroxide/pharmacology , I-kappa B Kinase/antagonists & inhibitors , Phosphorylation/drug effects , Protein Transport , Tumor Necrosis Factor-alpha/pharmacology , Ubiquitination/drug effects
15.
Article in English | WPRIM | ID: wpr-57559

ABSTRACT

The localization of estrogen (E2) has been clearly shown in hippocampus, called local hippocampal E2. It enhanced neuronal synaptic plasticity and protected neuron form cerebral ischemia, similar to those effects of exogenous E2. However, the interactive function of hippocampal and exogenous E2 on synaptic plasticity activation and neuroprotection is still elusive. By using hippocampal H19-7 cells, we demonstrated the local hippocampal E2 that totally suppressed by aromatase inhibitor anastrozole. Anastrozole also suppressed estrogen receptor (ER)beta, but not ERalpha, expression. Specific agonist of ERalpha (PPT) and ERbeta (DPN) restored ERbeta expression in anastrozole-treated cells. In combinatorial treatment with anastrozole and phosphoinositide kinase-3 (PI-3K) signaling inhibitor wortmannin, PPT could not improve hippocampal ERbeta expression. On the other hand, DPN induced basal ERbeta translocalization into nucleus of anastrozole-treated cells. Exogenous E2 increased synaptic plasticity markers expression in H19-7 cells. However, exogenous E2 could not enhance synaptic plasticity in anastrozole-treated group. Exogenous E2 also increased cell viability and B-cell lymphoma 2 (Bcl2) expression in H2O2-treated cells. In combined treatment of anastrozole and H2O2, exogenous E2 failed to enhance cell viability and Bcl2 expression in hippocampal H19-7 cells. Our results provided the evidence of the priming role of local hippocampal E2 on exogenous E2-enhanced synaptic plasticity and viability of hippocampal neurons.


Subject(s)
Androstadienes/pharmacology , Animals , Aromatase Inhibitors/pharmacology , Cell Line , Cell Survival/drug effects , Estrogen Receptor alpha/agonists , Estrogen Receptor beta/agonists , Estrogens/metabolism , Hippocampus/cytology , Hydrogen Peroxide/pharmacology , Nervous System/drug effects , Neuronal Plasticity/drug effects , Neuroprotective Agents , Nitriles/pharmacology , Phosphatidylinositol 3-Kinase/antagonists & inhibitors , Proto-Oncogene Proteins c-bcl-2/biosynthesis , Rats , Triazoles/pharmacology
16.
Int. j. odontostomatol. (Print) ; 6(3): 263-266, 2012. ilus, tab
Article in English | LILACS | ID: lil-676183

ABSTRACT

The aim was to evaluate the dissolution of porcine muscle using sodium hypochlorite in several concentrations and in combination with 3 percent hydrogen peroxide. Small pieces of porcine muscle were cut and their weight adjusted at 0.02g to be submerged in 1 ml of each test solution which was changed in 1 minute intervals until complete dissolution of the sample was observed. The 75 pieces of tissue were divided in 5 groups and different irrigant solutions were used as follows: Group 1, 5 percent sodium hypochlorite (NaOCl 5 percent). Group 2, 2.5 percent sodium hypochlorite (NaOCl 2.5 percent). Group 3, 2.5 percent sodium hypochlorite and 3 percent hydrogen peroxide alternately (NaOCl 2.5 percent + H2O2 3 percent). Group 4,3 percent hydrogen peroxide (H2O2), and group 5 used saline (NaCl 0.9 percent) as a negative control. For 5 percent sodium hypochlorite the mean time until complete dissolution of the sample was 17.5 minutes. The mean time for group 2 was 18.5, for group 3 was 64.6 minutes and for groups 4 and 5 there was no tissue dissolution after 120 minutes. To evaluate statistical significance ANOVA multi sample test was performed and Tukey post hoc test with significance level at P=0.05. Under the conditions of this study there were no significant differences with the use of sodium hypochlorite at 5 percent and 2.5 percent in terms of dissolution speed (P=0.6). The combination of sodium hypochlorite and hydrogen peroxide alternately caused a statistical significant delay in the dissolution of porcine muscle (P<0.05). The combination of sodium hypochlorite and hydrogen peroxide does not offer any benefit in terms of speed of dissolution of connective necrotic tissue...


El objetivo fue evaluar la disolución de tejido muscular porcino por acción del hipoclorito de sodio en varias concentraciones y en combinación con peróxido de hidrógeno al 3 por ciento. Se cortaron trozos de tejido muscular porcino y se ajustó su peso a 0,02 g para ser inmersos en 1 ml de cada una de las soluciones de irrigación de prueba hasta observar la total disolución de la muestra. 75 piezas de tejido fueron divididas en 5 grupos y se utilizaron diferentes soluciones de irrigación como se describe: Grupo 1, hipoclorito de sodio al 5 por ciento (NaOCl 5 por ciento). Grupo 2, hipoclorito de sodio al 2,5 por ciento (NaOCl 2,5 por ciento). Grupo 3, hipoclorito de sodio al 2,5 por ciento alternado con peróxido de hidrógeno al 3 por ciento (NaOCl 2,5 por ciento + H2O2 3 por ciento). Grupo 4, peróxido de hidrógeno al 3 por ciento (H2O2) y el grupo 5 utilizó solución salina (NaCl 0,9 por ciento) como control negativo. Para el hipoclorito de sodio al 5 por ciento la mediana del tiempo hasta la disolución total del tejido fue 17,5 minutos. La mediana del tiempo para el grupo 2 fue 18,5 para el grupo 3, 64,6 minutos y para los grupos 4 y 5 no se observó disolución del tejido de muestra tras 120 minutos. La significancia estadística se determinó con el test ANOVA multi muestra y se realizó test Tukey pos hoc con un nivel de significancia P=0,05. Bajo los parámetros de este estudio no hubo diferencia significativa con el uso de hipoclorito de sodio al 2,5 y 5 por ciento en términos de velocidad de disolución del tejido conectivo (P=0,6). La combinación de hipoclorito de sodio y peróxido de hidrógeno de forma alternada causó un retraso estadísticamente significativo en la disolución de tejido muscular porcino (P<0,05). El uso alternado de hipoclorito de sodio y peróxido de hidrógeno no ofrece ningún beneficio en términos de velocidad de disolución de tejido conectivo necrótico...


Subject(s)
Animals , Sodium Hypochlorite/pharmacology , Hydrogen Peroxide/pharmacology , Connective Tissue , Analysis of Variance , Dissolution , Root Canal Irrigants/pharmacology , Swine
17.
An. acad. bras. ciênc ; 83(4): 1403-1411, Dec. 2011. graf, tab
Article in English | LILACS | ID: lil-607433

ABSTRACT

The purpose of this study was to evaluate the beneficial effects of organic and conventional grapevine (Vitis labrusca L.) leaf extracts in reducing hydrogen peroxide-induced stress in the liver, heart and kidney of Wistar rats by measuring lipids and proteins damages (carbonyl assay), as well as the activity of the antioxidant enzymes superoxide dismutase and catalase. The preincubation with 5 mg/mL of organic and conventional grapevine (Vitis labrusca L.) leaf extracts prevented both lipids and proteins oxidative damages in all tissues analyzed. The organic leaf extract was able to restore superoxide dismutase (kidney and liver) and catalase (heart) activities, which were modified by the treatment with H2O2. The conventional extract was able to restore only the catalase activity in liver and heart tissues. The beneficial effects of the V labrusca leaf extract shown in this study could probably be important for formulating dietary supplements, as well as for developing new ingredients with improved antioxidant properties from other plant sources.


O objetivo deste estudo foi avaliar os efeitos benéficos de extratos de folhas de videira (Vitis labrusca L.) orgânicas e convencionais em reduzir o dano gerado pelo peróxido de hidrogênio no fígado, coração e rim de ratos Wistar, pela medida de danos a lipídios e a proteínas (Ensaio Carbonyl), como também a modulação sob a atividade das enzimas antioxi-dantes superoxido dismutase e catalase. A pré-incubação com 5 mg/mL de extratos de folhas de videira (Vitis labrusca L.) orgânicas e convencionais previnem ambos danos oxidativos a lipídios e proteínas em todos os tecidos analisados. O extrato de folha orgânica foi capaz de restabelecer a atividade das enzimas superóxido dismutase (rim e fígado) e catalase (coração), as quais foram modificadas pelo tratamento com peróxido de hidrogênio. O extrato convencional foi capaz de restabelecer apenas a enzima catalase no fígado e no coração. Os efeitos do extrato da folha V. labrusca mostrados neste estudo, provavelmente, poderiam ser importantes para a formulação de suplementos dietéticos, bem como para o desenvolvimento de novos ingredientes com propriedades antioxidantes provenientes de outras plantas.


Subject(s)
Animals , Male , Rats , Antioxidants/pharmacology , Oxidative Stress/drug effects , Plant Extracts/pharmacology , Protective Agents/pharmacology , Vitis/chemistry , Catalase/analysis , Catalase/drug effects , Heart/drug effects , Hydrogen Peroxide/pharmacology , Kidney/drug effects , Kidney/enzymology , Lipid Peroxidation/drug effects , Lipids/analysis , Liver/drug effects , Liver/enzymology , Plant Leaves/chemistry , Proteins/analysis , Proteins/drug effects , Rats, Wistar , Superoxide Dismutase
18.
Article in English | IMSEAR | ID: sea-139946

ABSTRACT

Context: To evaluate the effect of widely used endodontic irrigating solutions on root dentin microhardness and surface roughness. Materials and Methods: One hundred twenty, non-carious extracted human permanent incisor teeth were selected. The crowns of the teeth were sectioned and the roots were separated longitudinally to get 240 specimens. These specimens were then divided into six groups according to the irrigating solutions used. The solutions used were 5% and 2.5% NaOCl solutions, 3% H2 O2 , 17% EDTA solution, 0.2% chlorhexidine gluconate, and distilled water. Then, the specimens were subjected to microhardness and roughness testing. The data were analyzed using ANOVA and Tukey's multiple comparison tests. Results: The results of this study indicated that all irrigation solutions, except 0.2% chlorhexidine gluconate, decreased the microhardness of root dentin, and 3% H2 O2 and 0.2% chlorhexidine gluconate had no effect on surface roughness. Conclusions: Within the limitation of this study, it is concluded that 0.2% chlorhexidine gluconate seems to be an appropriate irrigation solution, because of its harmless effect on the microhardness and surface roughness of root canal dentin.


Subject(s)
Analysis of Variance , Chlorhexidine/analogs & derivatives , Chlorhexidine/pharmacology , Debridement/methods , Dental Pulp Cavity/drug effects , Dental Pulp Cavity/ultrastructure , Dentin/drug effects , Dentin/ultrastructure , Edetic Acid/pharmacology , Hardness , Humans , Hydrogen Peroxide/pharmacology , Root Canal Irrigants/pharmacology , Sodium Hypochlorite/pharmacology , Statistics, Nonparametric , Surface Properties , Therapeutic Irrigation/methods , Tooth Root
19.
Article in English | WPRIM | ID: wpr-48418

ABSTRACT

Biliverdin reductase A (BLVRA), an enzyme that converts biliverdin to bilirubin, has recently emerged as a key regulator of the cellular redox cycle. However, the role of BLVRA in the aging process remains unclear. To study the role of BLVRA in the aging process, we compared the stress responses of young and senescent human diploid fibroblasts (HDFs) to the reactive oxygen species (ROS) inducer, hydrogen peroxide (H2O2). H2O2 markedly induced BLVRA activity in young HDFs, but not in senescent HDFs. Additionally, depletion of BLVRA reduced the H2O2-dependent induction of heme oxygenase-1 (HO-1) in young HDFs, but not in senescent cells, suggesting an aging-dependent differential modulation of responses to oxidative stress. The role of BLVRA in the regulation of cellular senescence was confirmed when lentiviral RNAitransfected stable primary HDFs with reduced BLVRA expression showed upregulation of the CDK inhibitor family members p16, p53, and p21, followed by cell cycle arrest in G0-G1 phase with high expression of senescence-associated beta-galactosidase. Taken together, these data support the notion that BLVRA contributes significantly to modulation of the aging process by adjusting the cellular oxidative status.


Subject(s)
Age Factors , Blotting, Western , Cellular Senescence , Cell Cycle , Cells, Cultured , Enzyme Induction , Fibroblasts/physiology , G1 Phase , Heme Oxygenase-1/metabolism , Humans , Hydrogen Peroxide/pharmacology , Oxidative Stress , Oxidoreductases Acting on CH-CH Group Donors/metabolism , Protein Kinase Inhibitors/metabolism , RNA, Small Interfering , Reactive Oxygen Species/metabolism , beta-Galactosidase/genetics
20.
Article in English | WPRIM | ID: wpr-48414

ABSTRACT

Clusterin is a secretory glycoprotein, which is highly up-regulated in a variety of normal and injury tissues undergoing apoptosis including infarct region of the myocardium. Here, we report that clusterin protects H9c2 cardiomyocytes from H2O2-induced apoptosis by triggering the activation of Akt and GSK-3beta. Treatment with H2O2 induces apoptosis of H9c2 cells by promoting caspase cleavage and cytochrome c release from mitochondria. However, co-treatment with clusterin reverses the induction of apoptotic signaling by H2O2, thereby recovers cell viability. The protective effect of clusterin on H2O2-induced apoptosis is impaired by PI3K inhibitor LY294002, which effectively suppresses clusterin-induced activation of Akt and GSK-3beta. In addition, the protective effect of clusterin is independednt on its receptor megalin, because inhibition of megalin has no effect on clusturin-mediated Akt/GSK-3beta phosphoylation and H9c2 cell viability. Collectively, these results suggest that clusterin has a role protecting cardiomyocytes from oxidative stress and the Akt/GSK-3beta signaling mediates anti-apoptotic effect of clusterin.


Subject(s)
Animals , Apoptosis , Blotting, Western , Caspase 3/metabolism , Caspase 9/metabolism , Cell Line , Chromones/pharmacology , Clusterin/metabolism , Glycogen Synthase Kinase 3/metabolism , Humans , Hydrogen Peroxide/pharmacology , Low Density Lipoprotein Receptor-Related Protein-2/metabolism , Morpholines/pharmacology , Myocytes, Cardiac/metabolism , Oxidative Stress , Phosphatidylinositol 3-Kinases/metabolism , Proto-Oncogene Proteins c-akt/metabolism , RNA, Small Interfering , Rats , Reactive Oxygen Species/pharmacology , Reverse Transcriptase Polymerase Chain Reaction , Signal Transduction/drug effects
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