Hepatic oxidative stress in an animal model of sleep apnoea: effects of different duration of exposure

Background: Repeated apnoea events cause intermittent hypoxia (IH), which alters the function of various systems and produces free radicals and oxidative stress. Methods: We investigated hepatic oxidative stress in adult mice subjected to intermittent hypoxia, simulating sleep apnoea. Three groups were submitted to 21 days of IH (IH-21), 35 days of IH (IH-35), or 35 days of sham IH. We assessed the oxidative damage to lipids by TBARS and to DNA by comet assay; hepatic tissue inflammation was assessed in HE-stained slides. Antioxidants were gauged by catalase, superoxide dismutase, glutathione peroxidase activity and by total glutathione. Results: After IH-21, no significant change was observed in hepatic oxidative stress. After IH-35, significant oxidative stress, lipid peroxidation, DNA damage and reduction of endogenous antioxidants were detected. Conclusions: In an animal model of sleep apnoea, intermittent hypoxia causes liver damage due to oxidative stress after 35 days, but not after 21 days

THE EFFECT OF INTERMITTENT HYPOXIC TRAINING UNDER OXIDATIVE STRESS PARAMETERS IN WISTAR RATS FED ON STANDARD AND HIGH FAT DIET

Considerando-se que dietas ricas em gordura levam ao estresse oxidativo, causando lesões nas células e que o treinamento hipóxico intermitente (THI) aumenta as defesas antioxidantes endógenas em diversas situações, o objetivo deste estudo foi avaliar o efeito do THI em parâmetros de estresse oxidativo e defesas antioxidantes em fígado de ratos Wistar alimentados com dieta rica em gordura e/ou dieta padrão. Ratos Wistar foram divididos em grupos alimentados com dieta padrão ou rica em gordura. Os grupos foram submetidos a hipóxia intermitente (HI), 15 minutos HI (14-11% O2) intercalados com cinco minutos de re-oxigenação ou sessões de normóxia (N) (21% O2), por um período de duas horas diárias durante 30 dias. Os ratos Wistar alimentados com dieta padrão, e submetidas a HI, apresentaram uma redução de 37,7% na concentração de substâncias reativas ao ácido tiobarbitúrico (TBARS) e aumento de 34,66% e 39,8% no conteúdo de superóxido dismutase (SOD) e catalase (CAT), respectivamente, em comparação com o seu controlo (normoxia). No grupo com dieta rica em gordura, não houve diferença estatística entre os subgrupos HI e N. Nossos dados, que demonstram que o THI possui efeito antioxidante no fígado de ratos Wistar, argumentam em favor do uso alternativo de protocolos de hipoxia intermitente no tratamento de determinadas patologias

Redox profile in liver of Leporinus macrocephalus exposed to different dissolved oxygen levels

Aquatic organisms are continuously exposed to environmental variations, which can lead to physiological and biochemical alterations. Leporinus macrocephalus, known as piavuçu, is a migratory species that may be exposed to variations in dissolved oxygen levels. Studies evaluating oxidative changes undergone by this species in these conditions are scarce. Therefore, this investigation aimed at evaluating oxidative alterations in L. macrocephalus exposed to different oxygen levels for 96 h: 6. 12 ± 0. 18, 3. 99 ± 0. 17, 3. 22 ± 0. 17, 2. 47 ± 0. 30 and 0. 710 ± 0. 07 mg L -1. At the end of the experimental period, fish were euthanized and livers used to determine lipid hydroperoxides, thiobarbituric acid reactive substances, catalase, glutathione-S-transferase, superoxide dismutase and thiol groups, which are an indirect measure of reduced glutathione. Results indicated a decrease in the studied parameters in hypoxic situations, suggesting a possible metabolic depression. © 2011 Springer Science+Business Media B.V.Fil: Riffel, A. P. K.. Universidade Federal de Santa Maria; BrasilFil: Garcia, L. O.. Universidade Federal de Santa Maria; Brasil. Universidade Federal do Rio Grande do Norte; BrasilFil: Finamor, I. A.. Universidade Federal de Santa Maria; BrasilFil: Saccol, E.M.H.. Universidade Federal de Santa Maria; BrasilFil: Meira, M.. Universidade Federal de Santa Maria; BrasilFil: Kolberg, C.. Universidade Federal do Rio Grande do Sul; BrasilFil: Horst, A.. Universidade Federal do Rio Grande do Sul; BrasilFil: Partata, W.. Universidade Federal do Rio Grande do Sul; BrasilFil: Llesuy, Susana Francisca. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Baldisserotto, B.. Universidade Federal de Santa Maria; BrasilFil: Pavanato, M. A.. Universidade Federal de Santa Maria; Brasi

T2-weighted BOLD in human myocardium

The principal aim of this work is to test the viability of Blood Oxygenation Level Dependent (BOLD) measurements in human myocardium, an experiment which has seen promising attempts in recent literature. A central challenge to the ~uccess of these experiments has been in the limited scale of the measured effect; this work therefore includes efforts to separate the BOLD effect from noise and confounding signals. BOLD is then measured by intensity in MR images produced using Steady State Free Precession (SSFP) acquisition, weighted by a T2 preparation module to introduce the target contrast. Two modelling sections are included: first, the changes in physiology which influence the signal intensity in the MR images via the T2 dependence; and secondly the factors upon which the preparation depends, which are not entirely limited to the T2 of the tissue. These models are investigated with the aim of increasing the BOLD contrast and removing any other dependencies. An empirical model is shown to be suitable for the relationship between oxygenation and T2, and improvements are suggested and explained by thorough simulation ofthe preparation module. Compensation for a further confounding effect is also investigated: that of the increase in heart rate which accompanies the adenosine infusion used in the BOLD experiment protocol to reveal differences in the response of ischaemic and healthy tissue. The compensation is shown to reduce temporal variance in SI measurements, and to increase the separation between distributions of SI in tissue classes. A process of registration and segmentation is refined for sampling BOLD information from the SS FP images, and tested to show a low failure rate. Finally, the BOLD process is then tested in a set of human subjects including healthy volunteers and patients with coronary artery disease, investigating the consequent difference in tissue oxygenation. A significant difference is shown in the responses to stress of BOLD SI three tissue classes in these subjects.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

La correspondencia de Valencia : diario de noticias : eco imparcial de la opinión y de la prensa: Año XLI Número 17420 - 1918 Mayo 05

Copia digital. Madrid : Ministerio de Cultura. Subdirección General de Coordinación Bibliotecaria, 200

Long-Term Aspartame Administration Leads to Fibrosis, Inflammasome Activation, and Gluconeogenesis Impairment in the Liver of Mice

Background: Aspartame is an artificial sweetener used in foods and beverages worldwide. However, it is linked to oxidative stress, inflammation, and liver damage through mechanisms that are not fully elucidated yet. This work aimed to investigate the effects of long-term administration of aspartame on the oxidative and inflammatory mechanisms associated with liver fibrosis progression in mice. Methods: Mice were divided into two groups with six animals each: control and aspartame. Aspartame (80 mg/kg, via oral) or vehicle was administrated for 12 weeks. Results: Aspartame caused liver damage and elevated serum transaminase levels. Aspartame also generated liver fibrosis, as evidenced by histology analysis, and pro-fibrotic markers’ upregulation, including transforming growth factor β 1, collagen type I alpha 1, and alpha-smooth muscle actin. Furthermore, aspartame reduced nuclear factor erythroid 2-related factor 2 (Nrf2) activation and enzymatic antioxidant activity and increased lipid peroxidation, which triggered NOD-like receptor containing protein 3 (NLRP3) inflammasome activation and p53 induction. Furthermore, aspartame reduced peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α) levels, possibly through p53 activation. This PGC-1α deficiency could be responsible for the changes in lipid profile in serum, total lipid accumulation, and gluconeogenesis impairment in liver, evidenced by the gluconeogenic enzymes’ downregulation, thus causing hypoglycemia. Conclusions: This work provides new insights to understand the mechanisms related to the adverse effects of aspartame on liver tissue

Efecto de la adición de aceite esencial de Myrcia sylvatica (G. Mey.) DC (AEMS) en la dieta de dorada (Sparus aurata) bajo situaciones de estrés crónico producido por densidad

Trabajo presentado en el XV Congreso Nacional de Acuicultura y el I Congreso Ibérico de Acuicultura, celebrados en Huelva del 13 al 16 de octubre de 2015.[ES] Unas condiciones de cultivo inadecuadas (por ejemplo la alta densidad), causan estrés a los peces, afectando el metabolismo de lípidos, hidratos de carbono y proteínas. El objetivo de este estudio fue evaluar los efectos de la adición de aceite esencial de Myrcia sylvatica (AEMS) en la dieta de ejemplares de Sparus aurata en situaciones de baja y alta densidad. Los juveniles de dorada fueron distribuidos y alimentados con tres dietas experimentales durante tres meses: i) control, ii) 1,0 mL AEMS/kg de pienso, y iii) 2.0 mL AEMS/kg de pienso. Transcurrido este tiempo, cada grupo experimental fue dividido en dos nuevas condiciones: baja y alta densidad de carga (BD, 5 kg/m3 y AD, 40 kg/m3, respectivamente) para tener un total de seis grupos experimentales: i) control-BD, ii) control-AD, iii) 1,0 mL-BD, iv) 1,0 mL-AD, v) 2,0 mL-BD, y vi) 2,0 mL-AD). Después de 22 días bajo estas condiciones, 10 individuos de cada tratamiento fueron anestesiados y se extrajeron muestras de sangre e hígado para el análisis de cortisol y metabolitos. Nuestros resultados muestran que la adición de AEMS disminuye los niveles de cortisol en condiciones de BD y AD. Además, se observa que dietas suplementadas con dosis cercanas a 2,0 mL AEMS/kg de pienso originan una reorganización metabólica para poder afrontar la situación de estrés producido por la alta densidad de carga.[EN] Inadequate stocking densities (e.g. high stocking density) activated stress system, affecting the metabolism of lipids, carbohydrates and proteins. The aim of this study was to evaluate the effects of adding essential oil of Myrcia sylvatica (EOMS) in the diet of Sparus aurata juveniles held at different stocking densities. Juvenile specimens were distributed into the three experimental groups, feeding three different diets during three additional months: i) control, ii) 1.0 mL EOMS/kg of feed, and iii) 2.0 mL EOMS/kg feed. After that, each experimental group was divided in two different conditions: low and high stocking densities (LD-5 kg/m3 and HD-40 kg/m3, respectively) constituting a total of six different treatments: i) control-LD, ii) control-HD, iii) 1.0 mL-LD, iv) 1.0 mL-HD, v) 2.0 mL-LD, and vi) 2.0 mL-HD). After 22 days under these conditions, 10 individuals from each treatment were anesthetized and sampled for plasma and liver. These samples were analysed for cortisol and metabolites analysis. Our results shown that EOMS decreased plasma cortisol levels under LD and HD conditions. Moreover, it is observed that diets supplemented with 2.0 mL EOMS/kg of food originates a metabolic reorganization to cope with the stressful situation produced by higher stocking densities.Etiane M. H. Saccol y Y.A. Parrado-Sanabria contaron con el apoyo de becas de doctorado y máster de la Comisión de Formación de Personal de Nivel Superior (CAPES) y a la Asociación Universitaria Iberoamericana de Postgrado (AUIP), respectivamente. Este trabajo ha sido financiado por el proyecto AGL2013-48835-C2-1-R (MINECO, España) concedido a J.M. Mancera.N