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1.
Article in English | WPRIM | ID: wpr-939914

ABSTRACT

Impaired immunomodulatory capacity and oxidative stress are the key factors limiting the effectiveness of mesenchymal stem cell transplantation therapy. The present study was aimed to investigate the effects of jujuboside A (JuA) on the protective effect and immunomodulatory capacity of human umbilical cord mesenchymal stem cells (hUC-MSCs). Hydrogen peroxide was used to establish an oxidative damage model of hUC-MSCs, while PBMCs isolated from rats were used to evaluate the effect of JuA pre-treatment on the immunomodulatory capacity of hUC-MSCs. Furthermore, Hoechst 33258 staining, lactate dehydrogenase test, measurement of malondialdehyde, Western blot, high-performance liquid chromatography; and flow cytometry were performed. Our results indicated that JuA (25 μmol·L-1) promoted the proliferation of hUC-MSCs, but did not affect the differentiating capability of these cells. JuA pre-treatment inhibited apoptosis, prevented oxidative damage, and up-regulated the protein expression of nuclear factor-erythroid factor 2-related factor 2 and heme oxygenase 1 in hUC-MSCs in which oxidative stress was induced with H2O2. In addition, JuA pre-treatment enhanced the inhibitory effect of hUC-MSCs against abnormally activated PBMCs, which was related to stimulation of the expression and activity of indoleamine 2,3-dioxygenase. In conclusion, our results demonstrate that JuA pre-treatment can enhance the survival and immunomodulatory ability through pathways related to oxidative stress, providing a new option for the improvement of hUC-MSCs in the clinical setting.


Subject(s)
Animals , Humans , Rats , Cell Differentiation , Hydrogen Peroxide/metabolism , Mesenchymal Stem Cells , Oxidative Stress , Saponins , Umbilical Cord/metabolism
2.
Electron. j. biotechnol ; 30: 110-117, nov. 2017. graf, tab, ilus
Article in English | LILACS | ID: biblio-1021571

ABSTRACT

Background: Catalase (CAT) is an important enzyme that degrades H2O2 into H2O and O2. To obtain an efficient catalase, in this study, a new strain of high catalase-producing Serratia marcescens, named FZSF01, was screened and its catalase was purified and characterized. Results: After optimization of fermentation conditions, the yield of catalase produced by this strain was as high as 51,468 U/ml. This catalase was further purified using two steps: DEAE-fast flow and Sephedex-G150. The purified catalase showed a specific activity of 197,575 U/mg with a molecular mass of 58 kDa. This catalase exhibited high activity at 20­70°C and pH 5.0­11.0. Km of the catalase was approximately 68 mM, and Vmax was 1886.8 mol/min mg. This catalase was further identified by LC­MS/MS, and the encoding gene was cloned and expressed in Escherichia coli BL21 (DE3) with a production of 17,267 ± 2037 U/ml. Conclusions: To our knowledge, these results represent one of the highest fermentation levels reported among current catalase-producing strains. This FZSF01 catalase may be suitable for several industrial applications that comprise exposure to alkaline conditions and under a wide range of temperatures.


Subject(s)
Serratia marcescens/enzymology , Catalase/metabolism , Recombination, Genetic , Serratia marcescens/genetics , RNA, Ribosomal, 16S , Kinetics , Catalase/isolation & purification , Catalase/genetics , Chromatography, Liquid , Sequence Analysis, DNA , Electrophoresis , Escherichia coli/genetics , Escherichia coli/metabolism , Fermentation , Hydrogen Peroxide/metabolism
3.
Braz. j. microbiol ; 48(3): 537-543, July-Sept. 2017. graf
Article in English | LILACS | ID: biblio-889126

ABSTRACT

Abstract Metallothioneins are a superfamily of low-molecular-weight, cysteine (Cys)-rich proteins that are believed to play important roles in protection against metal toxicity and oxidative stress. The main purpose of this study was to investigate the effect of heterologous expression of a rice metallothionein isoform (OsMTI-1b) on the tolerance of Saccharomyces cerevisiae to Cd2+, H2O2 and ethanol stress. The gene encoding OsMTI-1b was cloned into p426GPD as a yeast expression vector. The new construct was transformed to competent cells of S. cerevisiae. After verification of heterologous expression of OsMTI-1b, the new strain and control were grown under stress conditions. In comparison to control strain, the transformed S. cerevisiae cells expressing OsMTI-1b showed more tolerance to Cd2+ and accumulated more Cd2+ ions when they were grown in the medium containing CdCl2. In addition, the heterologous expression of GST-OsMTI-1b conferred H2O2 and ethanol tolerance to S. cerevisiae cells. The results indicate that heterologous expression of plant MT isoforms can enhance the tolerance of S. cerevisiae to multiple stresses.


Subject(s)
Plant Proteins/genetics , Oryza/genetics , Saccharomyces cerevisiae/metabolism , Cadmium/metabolism , Gene Expression , Ethanol/metabolism , Hydrogen Peroxide/metabolism , Metallothionein/genetics , Plant Proteins/metabolism , Saccharomyces cerevisiae/genetics , Oxidative Stress , Protein Isoforms/genetics , Protein Isoforms/metabolism , Metallothionein/metabolism
4.
Int. j. morphol ; 34(2): 431-435, June 2016. ilus
Article in Spanish | LILACS | ID: lil-787016

ABSTRACT

El estrés oxidativo es definido como un desbalance entre la producción de oxidantes y antioxidantes. La inducción de tolerancia a estrés en los ovocitos conllevaría a un mejor desarrollo embrionario. En bovinos, la incubación de ovocitos maduros con diferentes estresores (térmicos, alta presión hidrostática, oxidativos) incrementaría la tasa de generación de blastocitos. Este estudio evalúa el efecto de la modulación del estado redox incrementando el estrés oxidativo con H2O2 en ovocitos maduros bajo condiciones de cultivo in vitro y su efecto sobre el potencial de desarrollo embrionario. Para ello, ovocitos procedentes de ovarios de matadero fueron madurados en medio TCM-199 suplementado durante 22­23 h, a 38,5 °C, 5 % CO2 y humedad a saturación. Al final de las 22­23 h se incubaron los ovocitos maduros con 0, 50, 100 y 200 µM H2O2. La fecundación in vitro se realizó co-incubando los ovocitos durante 18 h con una concentración final de 1x106 espermatozoides/mL. Los presuntos cigotos fueron denudados y cultivados en medio KSOM-0,4 % BSA a 38,5 °C en atmósfera de baja tensión de O2 (5 % O2, 5 % CO2 y 90 % N2) y humedad a saturación. El estrés oxidativo inducido con H2O2 a una concentración de 50 y 100 µM produce una tasa de división de los embriones similar al control (88,7 %, 83,2 % y 86,4 % respectivamente, p>0,05), disminuyendo significativamente al utilizar una concentración de 200 µM (58,8 %, p<0,05). Asimismo, H2O2 causó un efecto similar en la tasa de blastocitos con 50 µM (20,4 % vs. 25,8 % control, p>0.05) pero disminuyó significativamente con 100 y 200 µM (10,7 % y 3,3 % respectivamente, p<0,05). Es posible, que estos embriones resistentes al estrés oxidativo puedan tener una mayor sobrevida durante los procesos de criopreservación que generan altos niveles de especies reactivas de oxígeno en los embriones.


Oxidative stress is defined as an imbalance between the production of oxidants and antioxidants. The induction of stress tolerance in oocytes leads to a better embryonic development. In cattle incubating mature oocytes with different stressors (thermal, high hydrostatic pressure, oxidative) increase the generation rate of blastocysts. The purpose of this study was to evaluate the effect of modulating the redox state increasing the oxidative stress through H2O2 in mature oocyte under in vitro culture conditions and its effect on the potential of embryonic development. To do this, oocytes from slaughterhouse ovaries were matured in TCM-199 medium supplemented for 22­23 h at 38.5 °C, 5 % CO2 and humidified atmosphere. At the end of 22­23 h, the treatments with 0, 50, 100 and 200 µM H2O2 were applied for 1 h. IVF was performed co-incubating the eggs for 18 h with a final concentration of 1x106 sperm/mL. The presumptive zygotes were denuded and cultured in medium KSOM-0.4 % BSA to 38.5 °C in an atmosphere of low concentration of O2 (5 % O2, 5 % CO2 and 90 % N2) and humidified atmosphere. The results show that the induction of oxidative stress by H2O2 produces a similar effect using a concentration of 50 and 100 mM in the cleavage rate of embryos compared to control (88.7 %, 83.2 % and 86,4 % respectively, p>0.05) and decreasing significantly by using a concentration of 200 mM (58.8 %, p<0.05). Also, H2O2 caused a similar effect on the rate of blastocysts with 50 µM (20.4 % vs. 25.8 control, p>0.05) but decreased significantly with 100 and 200 µM (10.7 % and 3.3 % respectively, p<0.05). It is possible that these embryos resistant to oxidative stress may have a higher survival in the cryopreservation processes that generating high levels of reactive oxygen species.


Subject(s)
Animals , Cattle , Adaptation, Physiological , Embryo, Mammalian/physiology , Hydrogen Peroxide/metabolism , Oxidative Stress , Reactive Oxygen Species/metabolism , Blastocyst/metabolism , Fertilization in Vitro
5.
Biol. Res ; 49: 1-5, 2016. ilus, graf, tab
Article in English | LILACS | ID: biblio-950857

ABSTRACT

BACKGROUND: α-Farnesene is a volatile sesquiterpene synthesized by the plant mevalonate (MVA) pathway through the action of α-farnesene synthase. The α-farnesene synthase 1 (MdAFS1) gene was isolated from apple peel (var. white winterpearmain), and transformed into tobacco (Nicotiana tabacum NC89). The transgenic plants had faster stem elongation during vegetative growth and earlier flowering than wild type (WT). Our studies focused on the transgenic tobacco phenotype. RESULTS: The levels of chlorophyll and soluble protein decreased and a lower seed biomass and reduced net photosynthetic rate (Pn) in transgenic plants. Reactive oxygen species (ROS) such as hydrogen peroxide (H2O2) and superoxide radicals (O2._) had higher levels in transgenics compared to controls. Transgenic plants also had enhanced sensitivity to oxidative stress. The transcriptome of 8-week-old plants was studied to detect molecular changes. Differentially expressed unigene analysis showed that ubiquitin-mediated proteolysis, cell growth, and death unigenes were upregulated. Unigenes related to photosynthesis, antioxidant activity, and nitrogen metabolism were downregulated. Combined with the expression analysis of senescence marker genes, these results indicate that senescence started in the leaves of the transgenic plants at the vegetative growth stage. CONCLUSIONS: The antioxidative defense system was compromised and the accumulation of reactive oxygen species (ROS) played an important role in the premature aging of transgenic plants.


Subject(s)
Tobacco/physiology , Plants, Genetically Modified/physiology , Antioxidants/physiology , Photosynthesis/physiology , Sesquiterpenes/analysis , Sesquiterpenes/metabolism , Time Factors , Tobacco/genetics , Genetic Markers , Gene Expression/physiology , Plants, Genetically Modified/genetics , Reactive Oxygen Species/analysis , Reactive Oxygen Species/metabolism , Superoxides/analysis , Superoxides/metabolism , Plant Leaves/physiology , Oxidative Stress/physiology , Gene Expression Regulation, Plant/physiology , Real-Time Polymerase Chain Reaction , Hydrogen Peroxide/analysis , Hydrogen Peroxide/metabolism
6.
Rev. bras. epidemiol ; 18(1): 194-207, Jan-Mar/2015. tab
Article in Portuguese | LILACS | ID: lil-736436

ABSTRACT

OBJETIVO: Analisar os fatores pessoais associados à prevalência e duração dos benefícios auxílio-doença decorrentes de sinovite e tenossinovite (CID10 M65). MÉTODO: Estudo transversal referente aos benefícios auxílio-doença decorrentes de sinovite e tenossinovite concedidos pelo Instituto Nacional de Seguro Social aos empregados no Brasil em 2008. Dados sobre o ramo de atividade econômica (Classificação Nacional de Atividades Econômicas - CNAE divisão, classe), sexo, idade, espécie e duração dos benefícios foram coletados do Sistema Único de Benefícios. A população corresponde à média mensal dos vínculos empregatícios declarados ao Cadastro Nacional de Informações Sociais. RESULTADOS: Em 2008 foram concedidos 35.601 benefícios auxílio-doença decorrentes de sinovite e tenossinovite, com prevalência de 10,9/10.000 vínculos empregatícios. No conjunto dos benefícios auxílio-doença houve maior razão de prevalência (RP) acidentária (RP 1,2), sendo esta maior em mulheres (RP 3,3), e em trabalhadores com idade acima de 39 anos (RP 1,4). As CNAE 37-Esgoto (55,4) e 60-Atividade de rádio e TV (47,1) apresentaram as maiores prevalências, no entanto, 64-Atividade de serviços financeiros e 6422-Bancos múltiplos caracterizaram mais acidentes de trabalho (RP 3,2 e 3,8, respectivamente) e maior duração (70 e 73 dias, respectivamente). A maior duração de benefício ocorreu entre trabalhadores com idade superior a 39 anos. Tanto a CNAE-divisão 60-Atividade de rádio e TV, quanto a CNAE-classe 6010-Atividade de rádio apresentaram elevadas razões de feminilidade (RP 8,1 e 10,8, respectivamente). CONCLUSÃO: A incapacidade para o trabalho por sinovite e tenossinovite apresenta associação tanto da prevalência quanto da duração com o ramo de atividade, sexo, idade e espécie de benefício (previdenciário/acidentário). .


OBJECTIVE: To analyse the personal and occupational factors associated with the prevalence and duration of sickness benefit claims due to synovitis and tenosynovitis (CID10 M65). METHODS: Cross-sectional study regarding sickness benefit claims due to synovitis and tenosynovitis granted to employees by National Institute of Social Security in Brazil in 2008. Data on economic activity (Economic Activities National Classification - CNAE division, class), sex, age, type and duration of benefits were collected from the Unified Benefit System. The study's population consists of the average monthly employment contracts declared to the National Register of Social Information. RESULTS: In 2008, 35,601 employees were granted sickness benefits due to synovitis and tenosynovitis, with a prevalence of 10.9/10,000 employments. Sickness benefits showed higher prevalence rates (PR) for work-related claims (PR 1,2), mostly made by females (PR 3.3) and by workers older than 39 years (PR 1,4). The CNAE 37-Sewage (55.4) and 60-Broadcasting Activity (47.1) had the highest overall prevalence. However, the 64-Financial service activities, except insurance and pension funding and 6422-Multiple banks with commercial service had the highest rates of work-related claims (RP 3.2 and 3.8, respectively), and the longer duration (70 and 73 days, respectively). Workers older than 39 years had the highest durations of work disability claims. Both the CNAE-division 60-Broadcasting Activity, and the CNAE-class 6010-Radio showed a high activity ratio of females (PR 8.1 and 10.8, respectively). CONCLUSION: The work disability due to synovitis and tenosynovitis presents prevalence and duration associated with economic activity, sex, age and kind of benefit (non work-related and work-related claims). .


Subject(s)
Humans , Globins/chemistry , Hydrogen Peroxide/chemistry , Nerve Tissue Proteins/chemistry , Nitrites/chemistry , Amino Acid Sequence , Binding Sites , Catalysis , Cysteine/chemistry , Cysteine/metabolism , Disulfides/chemistry , Disulfides/metabolism , Globins/metabolism , Hydrogen Peroxide/metabolism , Kinetics , Models, Molecular , Molecular Sequence Data , Myoglobin/chemistry , Myoglobin/metabolism , Nerve Tissue Proteins/metabolism , Nitrites/metabolism , Oxidation-Reduction , Protein Conformation , Phenol/chemistry , Phenols/chemistry , Phenylacetates/chemistry , Tandem Mass Spectrometry
7.
Bauru; s.n; 2015. 119 p. ilus, graf.
Thesis in Portuguese | LILACS | ID: lil-794221

ABSTRACT

Os mastócitos (MCs) estão presentes tanto no periodonto normal quanto inflamado, em diferentes quantidades e em vários locais. Nos últimos anos, a eficácia e a contribuição dos MCs em eliminar bactérias, através de sua atividade microbicida intracelular, estão se tornando cada vez mais reconhecidas. Assim, a partir de MCs murinos desafiados in vitro com o periodontopatógeno Aggregatibacter actinomycetemcomitans (ATCC 29523) por 3, 5, 10 e 24 horas, o presente estudo teve como objetivo investigar a capacidade microbicida intracelular de MCs, e comparar com a capacidade microbicida de macrófagos peritoneais murinos (MPs), considerados fagócitos profissionais, por meio da contagem das unidades formadoras de colônias. Além disso, avaliou-se a produção e liberação de mediadores microbicidas, óxido nítrico (NO) e peróxido de hidrogênio (H2O2), por meio do método colorimétrico de Griess e pela degradação de substratos fluorescentes, respectivamente. Para a análise estatística, foram utilizados os testes estatísticos ANOVA Fatorial seguido do teste de Tukey e teste de correlação de Pearson (p<0.05). Nossos resultados revelaram que os MCs foram capazes de eliminar eficientemente o periodontopatógeno, principalmente após 10h de desafio intracelular. Comparando-se a atividade microbicida dos dois tipos celulares, verificou-se, nos períodos de 3h e 5h de desafio, um menor percentual de colônias viáveis no interior de MPs, em comparação aos MCs. Inversamente, nos períodos de 10h e 24h, observaram-se menores valores percentuais de colônias intracelulares nos MCs em relação aos MPs. Além disso, a produção/liberação de NO bem como, em menor proporção, de H2O2 pelos MCs foram concordantes com a sua capacidade microbicida. Este é o primeiro estudo que demonstra a eficiente ação microbicida intracelular de MCs murinos contra Aggregatibacter actinomycetemcomitans, com produção e liberação de substâncias potencialmente bactericidas, e de forma mais eficaz que os macrófagos...


Mast cells (MCs) are present in both normal and inflamed periodontal tissues, in varying amounts and locations. Recently, MCs contribution in eliminating bacteria and its effectiveness, through its intracellular microbicidal activity, have been increasingly recognized. Thus, this study aimed to investigate the intracellular microbicide capacity of MCs, and compare it with the microbicide capacity of murine peritoneal macrophages (MPs), considered professional phagocytes, by counting the colony forming units. Both cell types were challenged in vitro with periodontopathogen Aggregatibacter actinomycetemcomitans (ATCC 29523) by 3, 5, 10 and 24 hours. Additionally, the production and release of microbicidal agents, nitric oxide (NO) and hydrogen peroxide (H2O2) were evaluated by means of colorimetric Griess method and by the degradation of fluorescent substrates, respectively. Statistical analysis was performed by ANOVA Factorial test followed by Tukey and Pearson's correlation test (p <0.05). Our results revealed that MCs are able to efficiently eliminate periodontopathogen, mainly after 10 hours of intracellular challenge. The microbicidal activity of both cell types, in 3 and 5 hours of challenge showed a lower percentage of viable colonies inside MPs, compared to MCs. Contradictorily, in 10 and 24 hours a lower percentage of intracellular colonies in MCs was observed in relation to MPs. Moreover, the production/release of NO and, in minor proportion, of H2O2 by MCs was in agreement with its microbicidal capacity. Therefore, this is the first report to describe the intracellular microicidal activity of murine MCs against Aggregatibacter actinomycetemcomitans, concerning production and release of potentially bactericidal substances, which is more effective than macrophages. These results suggest the importance of these cells in pathogenesis and defense mechanisms of biofilm-associated periodontal disease...


Subject(s)
Animals , Male , Female , Mice , Aggregatibacter actinomycetemcomitans/growth & development , Bone Marrow Cells/physiology , Mast Cells/physiology , Colony Count, Microbial , Periodontal Diseases/pathology , Nitric Oxide/biosynthesis , Hydrogen Peroxide/metabolism , Time Factors
8.
Bauru; s.n; 2015. 119 p. ilus, graf.
Thesis in Portuguese | LILACS, BBO | ID: biblio-867426

ABSTRACT

Os mastócitos (MCs) estão presentes tanto no periodonto normal quanto inflamado, em diferentes quantidades e em vários locais. Nos últimos anos, a eficácia e a contribuição dos MCs em eliminar bactérias, através de sua atividade microbicida intracelular, estão se tornando cada vez mais reconhecidas. Assim, a partir de MCs murinos desafiados in vitro com o periodontopatógeno Aggregatibacter actinomycetemcomitans (ATCC 29523) por 3, 5, 10 e 24 horas, o presente estudo teve como objetivo investigar a capacidade microbicida intracelular de MCs, e comparar com a capacidade microbicida de macrófagos peritoneais murinos (MPs), considerados fagócitos profissionais, por meio da contagem das unidades formadoras de colônias. Além disso, avaliou-se a produção e liberação de mediadores microbicidas, óxido nítrico (NO) e peróxido de hidrogênio (H2O2), por meio do método colorimétrico de Griess e pela degradação de substratos fluorescentes, respectivamente. Para a análise estatística, foram utilizados os testes estatísticos ANOVA Fatorial seguido do teste de Tukey e teste de correlação de Pearson (p<0.05). Nossos resultados revelaram que os MCs foram capazes de eliminar eficientemente o periodontopatógeno, principalmente após 10h de desafio intracelular. Comparando-se a atividade microbicida dos dois tipos celulares, verificou-se, nos períodos de 3h e 5h de desafio, um menor percentual de colônias viáveis no interior de MPs, em comparação aos MCs. Inversamente, nos períodos de 10h e 24h, observaram-se menores valores percentuais de colônias intracelulares nos MCs em relação aos MPs. Além disso, a produção/liberação de NO bem como, em menor proporção, de H2O2 pelos MCs foram concordantes com a sua capacidade microbicida. Este é o primeiro estudo que demonstra a eficiente ação microbicida intracelular de MCs murinos contra Aggregatibacter actinomycetemcomitans, com produção e liberação de substâncias potencialmente bactericidas, e de forma mais eficaz que os macrófagos...


Mast cells (MCs) are present in both normal and inflamed periodontal tissues, in varying amounts and locations. Recently, MCs contribution in eliminating bacteria and its effectiveness, through its intracellular microbicidal activity, have been increasingly recognized. Thus, this study aimed to investigate the intracellular microbicide capacity of MCs, and compare it with the microbicide capacity of murine peritoneal macrophages (MPs), considered professional phagocytes, by counting the colony forming units. Both cell types were challenged in vitro with periodontopathogen Aggregatibacter actinomycetemcomitans (ATCC 29523) by 3, 5, 10 and 24 hours. Additionally, the production and release of microbicidal agents, nitric oxide (NO) and hydrogen peroxide (H2O2) were evaluated by means of colorimetric Griess method and by the degradation of fluorescent substrates, respectively. Statistical analysis was performed by ANOVA Factorial test followed by Tukey and Pearson's correlation test (p <0.05). Our results revealed that MCs are able to efficiently eliminate periodontopathogen, mainly after 10 hours of intracellular challenge. The microbicidal activity of both cell types, in 3 and 5 hours of challenge showed a lower percentage of viable colonies inside MPs, compared to MCs. Contradictorily, in 10 and 24 hours a lower percentage of intracellular colonies in MCs was observed in relation to MPs. Moreover, the production/release of NO and, in minor proportion, of H2O2 by MCs was in agreement with its microbicidal capacity. Therefore, this is the first report to describe the intracellular microicidal activity of murine MCs against Aggregatibacter actinomycetemcomitans, concerning production and release of potentially bactericidal substances, which is more effective than macrophages. These results suggest the importance of these cells in pathogenesis and defense mechanisms of biofilm-associated periodontal disease.


Subject(s)
Animals , Male , Female , Mice , Aggregatibacter actinomycetemcomitans/growth & development , Bone Marrow Cells/physiology , Mast Cells/physiology , Colony Count, Microbial , Periodontal Diseases/pathology , Nitric Oxide/biosynthesis , Hydrogen Peroxide/metabolism , Time Factors
9.
Indian J Biochem Biophys ; 2014 Oct; 51(5): 407-415
Article in English | IMSEAR | ID: sea-154272

ABSTRACT

The involvement of 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and contents of H2O2, malondialdehyde (MDA) and proline was investigated in determining salinity tolerance among seedlings of thirty chickpea (Cicer arietinum L.) genotypes having different pedigrees. Chickpea genotypes, including cultivars and advanced lines were grown for 7 days under control and salt stress (50 mM NaCl) conditions. The genotypes showed differential response to salt stress in terms of growth, DPPH radical scavenging activity and contents of H2O2, MDA and proline in seedlings. On the basis of seedling growth, the genotypes having better performance under stress conditions had reduced levels of H2O2 and MDA contents, but increased levels of proline and DPPH radical scavenging activity. Stress tolerance index for these parameters was also determined. Agglomerative hierarchal clustering by Pearson correlation coefficient grouped the genotypes into two major clusters — MC I and MC II. MC II and A1-1 sub-cluster of MC-I comprised mainly of genotypes that showed higher stress resistance levels for the respective parameters in comparison to genotypes in other sub-clusters. Thus, it is possible to identify salt-tolerant genotypes on the basis of above parameters without a field trial.


Subject(s)
Biphenyl Compounds/metabolism , Cicer/physiology , Free Radical Scavengers/metabolism , Hydrogen Peroxide/metabolism , Malondialdehyde/metabolism , Oxidative Stress/physiology , Picrates/metabolism , Proline/metabolism , Reactive Oxygen Species/metabolism , Salinity , Salt Tolerance/physiology , Seedlings/physiology
10.
J. bras. med ; 102(4)julho - agosto 2014. graf, ilus
Article in Portuguese | LILACS | ID: lil-725926

ABSTRACT

Os pacientes com diabetes mellitus (DM) apresentam maior prevalência de doenças tireoidianas que a população geral. A autoimunidade certamente é um fator-chave na relação entre essas disfunções endócrinas. Entretanto, outros mecanismos, como redução da captação de iodeto, da atividade tireoperoxidase e aumento do estresse oxidativo na glândula tireoide, também parecem contribuir para este fato. O presente trabalho visa rever aspectos importantes na relação entre DM e doenças tireoidianas, com especial ênfase nos mecanismos envolvidos no aumento do estresse oxidativo na glândula tireoide decorrente do DM...


Diabetes mellitus (DM) patients show a greater prevalence of thyroid disorders than general population. Autoimmunity is a key factor in the relation between these endocrine diseases. However, additional mechanisms, such as reduction of iodide uptake and thyroperoxidase activity, besides increased oxidative stress in the thyroid gland seem to contribute for this fact. The present work aims to review important aspects in the relation between DM and thyroid disease, with special emphasis in the mechanisms involved in the increased oxidative stress in the thyroid gland due to DM...


Subject(s)
Humans , Male , Female , Diabetes Mellitus, Type 1/complications , Diabetes Mellitus, Type 1/metabolism , Thyroid Diseases , Autoimmunity , Diabetes Complications/metabolism , Cardiovascular Diseases/etiology , Hyperthyroidism/complications , Thyroid Hormones/biosynthesis , Thyroid Hormones/metabolism , NADPH Oxidases/analysis , NADPH Oxidases/metabolism , Oxidative Stress , Hydrogen Peroxide/metabolism
11.
Biol. Res ; 47: 1-10, 2014. graf, tab
Article in English | LILACS | ID: biblio-950772

ABSTRACT

BACKGROUND: Based on the ethnomedicinal uses and the effective outcomes of natural products in various diseases, this study was designed to evaluate Isodon rugosus as possible remedy in oxidative stress, alzheimer's and other neurodegenerative diseases. Acetylecholinestrase (AChE) and butyrylcholinesterase (BChE) inhibitory activities of crude methanolic extract (Ir.Cr), resultant fractions (n-hexane (Ir.Hex), chloroform (Ir.Cf), ethyl acetate (Ir.EtAc), aqueous (Ir.Aq)), flavonoids (Ir.Flv) and crude saponins (Ir.Sp) of I. rugosus were investigated using Ellman's spectrophotometric method. Antioxidant potential of I. rugosus was determined using DPPH, H2O2 and ABTS free radicals scavenging assays. Total phenolic and flavonoids contents of plant extracts were determined and expressed in mg GAE/g dry weight and mg RTE/g of dry sample respectively. RESULTS: Among different fractions Ir.Flv and Ir.Cf exhibited highest inhibitory activity against AChE (87.44 ± 0.51, 83.73 ± 0.64%) and BChE (82.53 ± 0.71, 88.55 ± 0.77%) enzymes at 1 mg/ml with IC50 values of 45, 50 for AChE and 40, 70 µg/ml for BChE respectively. Activity of these fractions were comparable to galanthamine causing 96.00 ± 0.30 and 88.61 ± 0.43% inhibition of AChE and BChE at 1 mg/ml concentration with IC50 values of 20 and 47 µg/ml respectively. In antioxidant assays, Ir.Flv, Ir.Cf, and Ir.EtAc demonstrated highest radicals scavenging activities in DPPH and H2O2 assays which were comparable to ascorbic acid. Ir.Flv was found most potent with IC50 of 19 and 24 µg/ml against DPPH and H2O2 radicals respectively. Whereas antioxidant activates of plant samples against ABTS free radicals was moderate. Ir.Cf, Ir.EtAc and Ir.Cr showed high phenolic and flavonoid contents and concentrations of these compounds in different fractions correlated well to their antioxidant and anticholinestrase activities. CONCLUSION: It may be inferred from the current investigations that the Ir.Sp, Ir.Flv and various fractions of I. rugosus are good sources of anticholinesterase and antioxidant compounds. Different fractions can be subjected to activity guided isolation of bioactive compounds effective in neurological disorders.


Subject(s)
Saponins/analysis , Flavonoids/analysis , Plant Extracts/chemistry , Cholinesterase Inhibitors/analysis , Isodon/chemistry , Antioxidants/analysis , Picrates/metabolism , Acetylcholinesterase/drug effects , Saponins/isolation & purification , Spectrophotometry/methods , Sulfonic Acids/metabolism , Flavonoids/isolation & purification , Biphenyl Compounds/metabolism , Butyrylcholinesterase/drug effects , Chloroform , Free Radical Scavengers/metabolism , Oxidative Stress/drug effects , Inhibitory Concentration 50 , Isodon/classification , Isodon/enzymology , Plant Components, Aerial/chemistry , Complex Mixtures , Methanol , Benzothiazoles/metabolism , Free Radicals/analysis , Hexanes , Hydrogen Peroxide/metabolism , Medicine, Traditional , Acetates
12.
Article in English | WPRIM | ID: wpr-35685

ABSTRACT

This study investigated whether tempol, an anti-oxidant, protects against renal injury by modulating phosphatidylinositol 3-kinase (PI3K)-Akt-Forkhead homeobox O (FoxO) signaling. Mice received unilateral ureteral obstruction (UUO) surgery with or without administration of tempol. We evaluated renal damage, oxidative stress and the expression of PI3K, Akt, FoxO3a and their target molecules including manganese superoxide dismutase (MnSOD), catalase, Bax, and Bcl-2 on day 3 and day 7 after UUO. Tubulointerstitial fibrosis, collagen deposition, alpha-smooth muscle actin-positive area, and F4/80-positive macrophage infiltration were significantly lower in tempol-treated mice compared with control mice. The expression of PI3K, phosphorylated Akt, and phosphorylated FoxO3a markedly decreased in tempol-treated mice compared with control mice. Tempol prominently increased the expressions of MnSOD and catalase, and decreased the production of hydrogen peroxide and lipid peroxidation in the obstructed kidneys. Significantly less apoptosis, a lower ratio of Bax to Bcl-2 expression and fewer apoptotic cells in TUNEL staining, and decreased expression of transforming growth factor-beta1 were observed in the obstructed kidneys from tempol-treated mice compared with those from control mice. Tempol attenuates oxidative stress, inflammation, and fibrosis in the obstructed kidneys of UUO mice, and the modulation of PI3K-Akt-FoxO3a signaling may be involved in this pathogenesis.


Subject(s)
Animals , Male , Mice , Antioxidants/pharmacology , Collagen/metabolism , Cyclic N-Oxides/pharmacology , Fibrosis , Forkhead Transcription Factors/metabolism , Hydrogen Peroxide/metabolism , Kidney Diseases/drug therapy , Lipid Peroxidation , Mice, Inbred C57BL , Oxidative Stress/drug effects , Phosphatidylinositol 3-Kinases/metabolism , Phosphorylation/drug effects , Proto-Oncogene Proteins c-akt/metabolism , Severity of Illness Index , Signal Transduction/drug effects , Spin Labels , Superoxide Dismutase/metabolism , Ureteral Obstruction/complications
13.
Arq. bras. endocrinol. metab ; 57(8): 594-602, Nov. 2013. graf, tab
Article in English | LILACS | ID: lil-696898

ABSTRACT

OBJECTIVE: This study investigated the effect of interval training on blood biochemistry and immune parameters in type 1 diabetic rats. MATERIALS AND METHODS: Male Wistar rats were divided into four groups: sedentary (SE, n = 15), interval training (IT, n = 17), diabetic sedentary (DSE, n = 17), diabetic interval training (DIT, n = 17). Diabetes was induced by i.v. injection of streptozotocin (60 mg/kg). Swimming Interval Training consisted of 30-s exercise with 30-s rest, for 30 minutes, during 6 weeks, four times a week, with an overload of 15% of body mass. Plasma glucose, lactate, triacylglycerol and total cholesterol concentrations, phagocytic capacity, cationic vesicle content, and superoxide anion and hydrogen peroxide production by blood neutrophils and peritoneal macrophages were evaluated. Proliferation of mesenteric lymphocytes was also estimated. RESULTS: Interval training resulted in attenuation of the resting hyperglycemic state and decreased blood lipids in the DIT group. Diabetes increased the functionality of blood neutrophils and peritoneal macrophages in the DSE group. Interval training increased all functionality parameters of peritoneal macrophages in the IT group. Interval training also led to a twofold increase in the proliferation of mesenteric lymphocytes after 6 weeks of exercise in the DIT group. CONCLUSION: Low-volume high-intensity physical exercise attenuates hyperglycemia and dislipidemia induced by type 1 diabetes, and induces changes in the functionality of innate and acquired immunity.


OBJETIVO: Este estudo investigou os efeitos do treinamento intervalado sobre parâmetros bioquímicos e imunológicos em ratos diabéticos do tipo 1. MATERIAIS E MÉTODOS: Ratos Wistar machos foram divididos em quatro grupos: sedentário (SE, n = 15), treinamento intervalado (TI, n = 17), sedentário diabético (SED, n = 17) e treinamento intervalado diabético (TID, n = 17). O diabetes foi induzido por uma injeção intravenosa de estreptozotocina (60 mg/kg). O treinamento intervalado de natação consistiu de 30s de exercício com 30s de recuperação, 30 minutos, durante 6 semanas, 4 vezes por semana, com sobrecarga de 15% da massa corporal. Foram avaliados glicemia, lactato sanguíneo, concentração de triacilglicerol e colesterol total, capacidade fagocítica, conteúdo de vesículas catiô­nicas, produção de ânion superóxido e peróxido de hidrogênio por neutrófilos sanguíneos e macrófagos peritoneais. A proliferação de linfócitos mesentéricos também foi avaliada. RESULTADOS: O treinamento intervalado resultou em atenuação do estado hiperglicêmico e diminuiu os lipídeos sanguíneos no grupo TID. O diabetes aumentou a funcionalidade dos neutrófilos sanguíneos e macrófagos peritoneais do grupo SED. O treinamento intervalado aumentou todos os parâmetros funcionais dos macrófagos peritoneais do grupo TI. O treinamento intervalado também aumentou duas vezes a proliferação dos linfócitos mesentéricos após seis semanas de exercício do grupo TID. CONCLUSÃO: O treinamento intervalado atenua a hiperglicemia e a dislipidemia induzida pelo diabetes do tipo 1 e induz mudanças na funcionalidade da imunidade inata e adquirida.


Subject(s)
Animals , Male , Diabetes Mellitus, Experimental/chemically induced , Diabetes Mellitus, Experimental/metabolism , Diabetes Mellitus, Type 1/metabolism , Dyslipidemias/etiology , Hyperglycemia/etiology , Physical Conditioning, Animal/methods , Biomarkers , Blood Glucose/metabolism , Cell Proliferation , Disease Models, Animal , Diabetes Mellitus, Type 1/complications , Hydrogen Peroxide/metabolism , Neutrophils/metabolism , Phagocytosis/physiology , Rats, Wistar , Sedentary Behavior , Streptozocin/pharmacology , Superoxides/metabolism
14.
Article in English | IMSEAR | ID: sea-162942

ABSTRACT

Aim: To correlate H2O2 production of Lactobacillus species with the Nugent scores of young Nigerian women in order to assess their vaginal health. Study Design: Cross-sectional study. Place and Duration of Study: Departments of Medical Microbiology & Parasitology, Biochemistry and Obstetrics and Gynaecology, College of Medicine of the University of Lagos, between May and august 2009. Methodology: Ninety- seven isolates of Lactobacillus from eighty-two women without Bacterial vaginosis (BV) and fifteen women with BV were used for the study. BV was diagnosed using Nugent scoring method. Lactobacilli were isolated using MRS agar and categorized into facultative anaerobes and strict anaerobes. Hydrogen peroxide was detected and measured by titration using dilute sulphuric acid and reaction stopped with potassium permanganate. Results: Out of 97 isolates studied, 76 (78%) were facultative anaerobes, while 21 (22%) were strict anaerobes. The facultative anaerobes were obtained from 11 of 15 women with BV and 65 of 82 women without BV. Forty- nine (50.51%) of the 97 isolates produced H2O2. Forty- four of the H2O2 producers were from women without BV while five were from women with BV. Majority (67%) of the strains obtained from women with BV were non-hydrogen peroxide producing. Proportion of H2O2 producing Lactobacillus by Nugent score were 70%, 43% and 33% in negative, intermediate and BV Nugent scores respectively. There was no significant difference between the mean concentrations of H2O2 production in the various Nugent scores. Conclusion: The overall rate of hydrogen peroxide production was low. While the rates of hydrogen peroxide production correlated with Nugent scores, being highest in negative Nugent scores and lowest with BV scores, the concentration of hydrogen peroxide produced had no association with Nugent scores. The Nigerian women studied might have a relatively high susceptibility rate to vaginal infections.


Subject(s)
Adult , Female , Humans , Hydrogen Peroxide/metabolism , Lactobacillus/metabolism , Lactobacillus/physiology , Nigeria , Research Design/methods , Vaginosis, Bacterial/metabolism , Young Adult
15.
Indian J Biochem Biophys ; 2013 Aug; 50(4): 318-325
Article in English | IMSEAR | ID: sea-148614

ABSTRACT

The individual and interactive effects of supplemental UV-B (sUV-B) (ambient + 7.2 kJ m-2 d-1) and elevated O3 (ambient + 10 ppb) were evaluated under field conditions using open top chambers on two cultivars, Padmini and T-397 of linseed (Linum usitatissimum L.). Mean monthly surface level of O3 concentrations varied from 27.7 ppb to 59.0 ppb during the experimental period. Both UV-B and O3 induced the production of ROS (H2O2 and O2.-), resulting in significant damage of membranes due to lipid peroxidation and electrolyte leakage. Synthesis of secondary metabolites (flavonoids, anthocyanin, lignin and wax) was also enhanced in all the treatments, whereas biomass and yield were reduced. Alterations in frequency of stomata and wax distribution were also observed through scanning electron microscopy (SEM). Cultivar Padmini was found to be more sensitive because of higher damage of membrane vis-a-vis reduction in biomass and seed yield. However, concentrations of flavonoids, anthocyanin, lignin and wax were higher in T-397, suggesting its relative resistance against applied stress. Combined exposure of sUV-B and O3 was less harmful, as compared to their individual treatment. Among the three treatments, O3 was found to be more detrimental for overall growth and sUV-B for economic yield.


Subject(s)
Adaptation, Physiological/drug effects , Adaptation, Physiological/radiation effects , Anthocyanins/metabolism , Biomass , Flax/drug effects , Flax/metabolism , Flax/physiology , Flax/radiation effects , Hydrogen Peroxide/metabolism , Lignin/metabolism , Lipid Peroxidation/drug effects , Lipid Peroxidation/radiation effects , Ozone/pharmacology , Plant Leaves/drug effects , Plant Leaves/metabolism , Plant Leaves/radiation effects , Reactive Oxygen Species/metabolism , Stress, Physiological/drug effects , Stress, Physiological/radiation effects , Superoxides/metabolism , Surface Properties , Ultraviolet Rays/adverse effects , Waxes/metabolism
16.
Indian J Exp Biol ; 2013 Jul; 51(7): 515-521
Article in English | IMSEAR | ID: sea-147622

ABSTRACT

Since aging is the most important risk factor for variety of diseases, the discovery of a wide range of chemical modulators of aging in model organisms encourages new strategies for targeting age associated diseases. Simple genetic manipulation leads to long-lived and healthy animals, so any compound which could have similar effect would prove a boon to mankind. In the present study, effect of different pharmacological doses (1.0, 0.1, 0.01 and 0.001 mg/mL) of O. sanctum crude extract were used to determine their impact on life span, thermotolerance and ROS scavenging activities in C. elegans. The results revealed that 1 mg/mL of O. sanctum extract significantly extended the life span of C. elegans. The extract also proved to be a strong free radical scavenger and increased resistance against thermal stress. It is also suggested that the protective and life span extending action of the crude extract is not only due to its antioxidant capacity but may also be mediated by modulation of some signaling pathways. Thus, in addition to all the known medicinal property of Ocimum, it is capable of increasing stress tolerance and life span in C. elegans.


Subject(s)
Aging/drug effects , Animals , Antioxidants/pharmacology , Caenorhabditis elegans/drug effects , Caenorhabditis elegans/growth & development , Caenorhabditis elegans/metabolism , Caenorhabditis elegans Proteins/genetics , Caenorhabditis elegans Proteins/metabolism , Cell Proliferation , Chemotaxis/drug effects , Complex Mixtures/pharmacology , Environment , Free Radical Scavengers/pharmacology , HSP70 Heat-Shock Proteins/genetics , HSP70 Heat-Shock Proteins/metabolism , Hot Temperature , Hydrogen Peroxide/metabolism , Ocimum/chemistry , Oxidative Stress/drug effects , RNA, Messenger/genetics , Real-Time Polymerase Chain Reaction , Reverse Transcriptase Polymerase Chain Reaction , Signal Transduction/drug effects , Sirtuins/genetics , Sirtuins/metabolism
17.
Indian J Biochem Biophys ; 2013 Apr; 50(2): 150-158
Article in English | IMSEAR | ID: sea-147298

ABSTRACT

The role of oxidative stress management was evaluated in two maize (Zea mays L.) genotypes — Parkash (drought-resistant) and Paras (drought-sensitive), subjected to drought stress during reproductive stage. Alterations in their antioxidant pools — glutathione (GSH) and ascorbic acid (AsA) combined with activities of enzymes glutathione reductase (GR), ascorbate peroxidase (APX), peroxidase (POX) and catalase (CAT) involved in defense against oxidative stress and stress parameters, namely chlorophyll (Chl), hydrogen peroxide (H2O2) and malondialdehyde (MDA) were investigated in flag leaves from silk emergence till maturity. The drought caused transient increase in GR, APX, POX and CAT activities in drought-tolerant genotype (Parkash) which decreased at later stages with the extended period of drought stress. However, in Paras, drought stress caused decrease in activities of GR and CAT from initial period of stress till the end of experiment, except for POX which showed slight increase in activity. A significant increase in GSH content was observed in Parkash till 35 days after silking (DAS), whereas in Paras, GSH content remained lower than irrigated till maturity. Parkash which had higher AsA and Chl contents, also showed lower H2O2 and MDA levels than Paras under drought stress conditions. However, at the later stages, decline in antioxidant enzyme activities in Parkash due to severe drought stress led to enhanced membrane damage, as revealed by the accumulation of MDA. Our data indicated that significant activation of antioxidant system in Parkash might be responsible for its drought-tolerant behavior under drought stress and helped it to cope with the stress up to a definite period. Thus, the results indicate that antioxidant status and lipid peroxidation in flag leaves can be used as indices of drought tolerance in maize plants and also as potential biochemical targets for the crop improvement programmes to develop drought-tolerant cultivars.


Subject(s)
Antioxidants/metabolism , Ascorbate Peroxidases/metabolism , Ascorbic Acid/metabolism , Catalase/metabolism , Crosses, Genetic , Droughts , Genotype , Glutathione Reductase/metabolism , Hydrogen Peroxide/metabolism , Lipid Peroxidation , Oxidative Stress , Peroxidase/metabolism , Peroxidases/metabolism , Plant Leaves/metabolism , Time Factors , Zea mays/genetics , Zea mays/physiology
18.
Article in English | WPRIM | ID: wpr-74490

ABSTRACT

Previous evidence supports the important role that oxidative stress (OxS) plays in metabolic syndrome (MetS)-related manifestations. We determined the relationship between the number of MetS components and the degree of OxS in MetS patients. In this comparative cross-sectional study from the LIPGENE cohort, a total of 91 MetS patients (43 men and 48 women; aged between 45 and 68 years) were divided into four groups based on the number of MetS components: subjects with 2, 3, 4 and 5 MetS components (n=20, 31, 28 and 12, respectively). We measured ischemic reactive hyperemia (IRH), plasma levels of soluble vascular cell adhesion molecule-1 (sVCAM-1), total nitrite, lipid peroxidation products (LPO), hydrogen peroxide (H2O2), superoxide dismutase (SOD) and glutathione peroxidase (GPx) plasma activities. sVCAM-1, H2O2 and LPO levels were lower in subjects with 2 or 3 MetS components than subjects with 4 or 5 MetS components. IRH and total nitrite levels were higher in subjects with 2 or 3 MetS components than subjects with 4 or 5 MetS components. SOD and GPx activities were lower in subjects with 2 MetS components than subjects with 4 or 5 MetS components. Waist circumference, weight, age, homeostatic model assessment-beta, triglycerides (TGs), high-density lipoprotein and sVCAM-1 levels were significantly correlated with SOD activity. MetS subjects with more MetS components may have a higher OxS level. Furthermore, association between SOD activity and MetS components may indicate that this variable could be the most relevant OxS biomarker in patients suffering from MetS and could be used as a predictive tool to determine the degree of the underlying OxS in MetS.


Subject(s)
Aged , Female , Humans , Male , Middle Aged , Anthropometry , Antioxidants/metabolism , Biomarkers/metabolism , Blood Pressure , Endothelium, Vascular/pathology , Glutathione Peroxidase/blood , Hydrogen Peroxide/metabolism , Hyperemia/blood , Metabolic Syndrome/blood , Nitrites/blood , Oxidative Stress , Regression Analysis , Superoxide Dismutase/blood , Vascular Cell Adhesion Molecule-1/metabolism
19.
Braz. j. med. biol. res ; 45(8): 701-710, Aug. 2012. ilus
Article in English | LILACS | ID: lil-643655

ABSTRACT

Apatone™, a combination of menadione (2-methyl-1,4-naphthoquinone, VK3) and ascorbic acid (vitamin C, VC) is a new strategy for cancer treatment. Part of its effect on tumor cells is related to the cellular pro-oxidative imbalance provoked by the generation of hydrogen peroxide (H2O2) through naphthoquinone redox cycling. In this study, we attempted to find new naphthoquinone derivatives that would increase the efficiency of H2O2 production, thereby potentially increasing its efficacy for cancer treatment. The presence of an electron-withdrawing group in the naphthoquinone moiety had a direct effect on the efficiency of H2O2 production. The compound 2-bromo-1,4-naphthoquinone (BrQ), in which the bromine atom substituted the methyl group in VK3, was approximately 10- and 19-fold more efficient than VK3 in terms of oxygen consumption and H2O2 production, respectively. The ratio [H2O2]produced / [naphthoquinone]consumed was 68 ± 11 and 5.8 ± 0.2 (µM/µM) for BrQ and VK3, respectively, indicating a higher efficacy of BrQ as a catalyst for the autoxidation of ascorbic acid. Both VK3 and BrQ reacted with glutathione (GSH), but BrQ was the more effective substrate. Part of GSH was incorporated into the naphthoquinone, producing a nucleophilic substitution product (Q-SG). The depletion of BrQ by GSH did not prevent its redox capacity since Q-SG was also able to catalyze the production of reactive oxygen species. VK3/VC has already been submitted to clinical trials for the treatment of prostate cancer and has demonstrated promising results. However, replacement of VK3 with BrQ will open new lines of investigation regarding this approach to cancer treatment.


Subject(s)
Humans , Antineoplastic Agents/pharmacology , Ascorbic Acid/pharmacology , Hydrogen Peroxide/metabolism , Naphthoquinones/pharmacology , Reactive Oxygen Species , Antineoplastic Agents/chemistry , Ascorbic Acid/chemistry , Drug Combinations , Drug Substitution , Naphthoquinones/chemistry , Oxidation-Reduction/drug effects , Oxygen Consumption/drug effects , Structure-Activity Relationship , Tumor Cells, Cultured/drug effects , /chemistry , /pharmacology
20.
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
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