RESUMEN
High-fat diet (HFD)-fed mice show obesity with development of liver steatosis and a proinflammatory state without establishing an inflammatory reaction. The aim of this work was to assess the hypothesis that eicosapentaenoic acid (EPA) plus hydroxytyrosol (HT) supplementation prevents the inflammatory reaction through enhancement in the hepatic resolvin content in HFD-fed mice. Male C57BL/6J mice were fed an HFD or a control diet and supplemented with EPA (50 mg/kg/day) and HT (5 mg/kg/day) or their respective vehicles for 12 weeks. Measurements include liver levels of EPA, DHA and palmitate (gas chromatography), liver resolvins and triglyceride (TG) and serum aspartate transaminase (AST) (specific kits) and hepatic and serum inflammatory markers (quantitative polymerase chain reaction and enzyme-linked immunosorbent assay). Compared to CD, HFD induced body weight gain, liver steatosis and TG accumulation, with up-regulation of proinflammatory markers in the absence of histological inflammation or serum AST changes; these results were accompanied by higher hepatic levels of resolvins RvE1, RvE2, RvD1 and RvD2, with decreases in EPA and DHA contents. EPA+HT supplementation in HFD feeding synergistically reduced the steatosis score over individual treatments and increased the hepatic levels of EPA, DHA and resolvins, with attenuation of proinflammatory markers. Lack of progression of HFD-induced proinflammatory state into overt inflammation is associated with resolvin up-regulation, which is further increased by EPA+HT supplementation eliciting steatosis attenuation. These findings point to the importance of combined protocols in hepatoprotection due to the involvement of cross-talk mechanisms, which increase effectiveness and diminish dosages, avoiding undesirable effects.
Asunto(s)
Dieta Alta en Grasa/efectos adversos , Ácido Eicosapentaenoico/farmacología , Hepatitis/dietoterapia , Hígado/efectos de los fármacos , Alcohol Feniletílico/análogos & derivados , Animales , Suplementos Dietéticos , Ácidos Docosahexaenoicos/metabolismo , Ácido Eicosapentaenoico/análogos & derivados , Ácido Eicosapentaenoico/metabolismo , Ácidos Grasos/metabolismo , Hepatitis/etiología , Hepatitis/metabolismo , Hígado/metabolismo , Masculino , Ratones Endogámicos C57BL , FN-kappa B/metabolismo , Alcohol Feniletílico/farmacologíaRESUMEN
Liver preconditioning by a docosahexaenoic acid (DHA) and triiodothyronine (T3) combined protocol underlies peroxisome-proliferator activated receptor α (PPARα)-fibroblast growth factor 21 (FGF21) upregulation, the study of the regulatory mechanisms involved being the aim of this work. Combined DHA (daily doses of 300 mg kg-1 for 3 days)-T3 (0.05 mg kg-1 at the fourth day) administration elicited higher levels of liver DHA and serum T3, with enhanced hepatic nuclear/cytosolic PPARα ratios, upregulation of FGF21 and ß-Klotho expression, and a small reduction in that of FGF receptor 1 (FGFR1), compared with the respective controls. Concomitantly, the components of the FGF21 cascade extracellular-signal-regulated kinase 1/2 (ERK1/2), FGF receptor substrate 2α (FRS2α), cFos, ribosomal S6 kinase 1 (RSK1), liver kinase B1 (LKB1), and AMP-activated protein kinase (AMPK) were activated. The upregulation of liver PPARα-FGF21-AMPK signaling by the combined DHA-T3 protocol resulted in values significantly higher than those elicited by the addition of the data obtained for DHA and T3 alone. It is concluded that combined DHA-T3 supplementation achieves synergistic effects on liver PPARα-FGF21-AMPK signaling, which may result in significant metabolic changes associated with energy expenditure that are of importance in the treatment of obesity and other metabolic disorders.
Asunto(s)
Ácidos Docosahexaenoicos/administración & dosificación , Factores de Crecimiento de Fibroblastos/metabolismo , Glucuronidasa/metabolismo , Hígado/metabolismo , Enfermedades Metabólicas/tratamiento farmacológico , Triyodotironina/administración & dosificación , Proteínas Quinasas Activadas por AMP/genética , Proteínas Quinasas Activadas por AMP/metabolismo , Animales , Metabolismo Energético/efectos de los fármacos , Factores de Crecimiento de Fibroblastos/genética , Glucuronidasa/genética , Humanos , Proteínas Klotho , Hígado/efectos de los fármacos , Hígado/enzimología , Masculino , Enfermedades Metabólicas/genética , Enfermedades Metabólicas/metabolismo , Enfermedades Metabólicas/fisiopatología , PPAR alfa/genética , PPAR alfa/metabolismo , Ratas , Ratas Sprague-Dawley , Transducción de Señal/efectos de los fármacos , Estrés Fisiológico/efectos de los fármacos , Regulación hacia Arriba/efectos de los fármacosRESUMEN
AMP-activated protein kinase (AMPK) is a sensor of energy status supporting cellular energy homeostasis that may represent the metabolic basis for 3,3,,5-triiodo-L-thyronine (T3) liver preconditioning. Functionally transient hyperthyroid state induced by T3 (single dose of 0.1 mg/kg) in fed rats led to upregulation of mRNA expression (RT-PCR) and protein phosphorylation (Western blot) of hepatic AMPK at 8 to 36 h after treatment. AMPK Thr 172 phosphorylation induced by T3 is associated with enhanced mRNA expression of the upstream kinases Ca2+ -calmodulin-dependent protein kinase kinase-beta (CaMKKbeta) and transforming growth-factor-beta-activated kinase-1 (TAK1), with increased protein levels of CaMKKbeta and higher TAK1 phosphorylation, without changes in those of the liver kinase B1 (LKB1) signaling pathway. Liver contents of AMP and ADP were augmented by 291 percent and 44 percent by T3 compared to control values (p less than 0.05), respectively, whereas those of ATP decreased by 64% (p less than 0.05), with no significant changes in the total content of adenine nucleotides (AMP + ADP + ATP) at 24 h after T3 administration. Consequently, hepatic ATP/ADP content ratios exhibited 64 percent diminution (p less than 0.05) and those of AMP/ATP increased by 425 percent (p less than 0.05) in T3-treated rats over controls. It is concluded that in vivoT3 administration triggers liver AMPK upregulation in association with significant enhancements in AMPK mRNA expression, AMPK phosphorylation coupled to CaMKKbeta and TAK1 activation, and in AMP/ATP ratios, which may promote enhanced AMPK activity to support T3-induced energy consuming processes such as those of liver preconditioning.
Asunto(s)
Proteínas Quinasas Activadas por AMP/metabolismo , Quinasa de la Proteína Quinasa Dependiente de Calcio-Calmodulina/genética , Hígado/metabolismo , Quinasas Quinasa Quinasa PAM/genética , Proteínas Serina-Treonina Quinasas/genética , Triyodotironina/farmacología , Quinasas de la Proteína-Quinasa Activada por el AMP , Animales , Metabolismo Energético , Masculino , Fosforilación , ARN Mensajero/análisis , Ratas , Ratas Sprague-DawleyRESUMEN
Nonalcoholic fatty liver disease (NAFLD) is the most important cause of chronic liver disease and is considered the hepatic manifestation of the metabolic syndrome associated with diabetes mellitus type 2. The prevalence of NAFLD in the general population reaches 15-20%. It is also estimated that nonalcoholic steatohepatitis (NASH) affects 3% of the population. NAFLD refers to a wide spectrum of liver damage, which ranges from simple steatosis or intracellular triglyceride accumulation, to inflammation (NASH), fibrosis and cirrhosis. The mechanisms involved in the accumulation of triglycerides in the liver and subsequent hepatocellular damage are multifactorial and are not completely understood. However, metabolic changes such as insulin resistance (IR) are developed, being a common factor in the retention of fatty acids (FA) within the hepatocytes with oxidation and production of free radicals at the mitochondrial level, which are capable of causing lipid peroxidation, cytokine production, and necrosis. In addition, there are alterations in the hepatic bioavailability of long chain n-3 polyunsaturated fatty acids, conditions that alter the expression of a series of transcriptional factors involved in lipolytic and lipogenic processes in the liver. A greater knowledge of the etiopathogenic mechanisms of NAFLD is fundamental for the development of future effective therapeutic strategies. The pathophysiological fundamentals of liver steatosis are analyzed in this study.
Asunto(s)
Hígado Graso/metabolismo , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/metabolismo , Ácidos Grasos/metabolismo , Hígado Graso/complicaciones , Hígado Graso/etiología , Hígado Graso/genética , Hígado Graso/fisiopatología , Humanos , Resistencia a la Insulina , Síndrome Metabólico/complicaciones , Síndrome Metabólico/metabolismo , Enfermedad del Hígado Graso no Alcohólico , Factores de TranscripciónRESUMEN
Objetivo: Determinar la asociación entre variables relacionadas con la calidad de la consulta nutricional y la percepción del paciente en el éxito del tratamiento para el control del peso corporal en un grupo de mujeres mayores de 20 años, habitantes de la Ciudad Autónoma de Buenos Aires o del Gran Buenos Aires. Metodología: Diseño observacional, transversal de correlación. Muestreo aleatorio simple de 97 mujeres que concurrieron por lo menos una vez a una consulta nutricional llevada a cabo por un Licenciado en Nutrición. Se realizó encuesta estructurada y voluntaria analizando como variable dependiente la percepción del éxito del tratamiento nutricional y como variables independientes, tres variables relacionadas con la calidad de la atención, como la escucha del profesional (buena, regular o mala), indicaciones adecuadas a gustos, hábitos y tolerancias digestivas y tipo de material entregado en la consulta. Resultados: Del total de la muestra estudiada el 61,9% percibió como exitoso a su último tratamiento para el control del peso corporal. Para la mayoría el ámbito físico donde se desarrolló la consulta fue adecuado (95,9%), siendo suficiente el tiempo destinado a la misma (89,7%), con buena escucha llevada a cabo por el profesional (75,3%). La percepción del éxito fue asociada significativamente con una buena escucha del profesional en la consulta (p: 0,0001) y con el manejo de indicaciones adecuadas a los gustos y hábitos de las pacientes (p: 0,002). No se observó asociación entre las indicaciones adecuadas a la tolerancia digestiva y el tipo de material empleado con la percepción de éxito en la consulta nutricional. Conclusiones: La percepción del éxito en el tratamiento nutricional fue asociada significativamente con una buena escucha por parte del profesional en la consulta e indicaciones adecuadas en cuanto a sus gustos y hábitos alimentarios.
Asunto(s)
Humanos , Peso Corporal , Atención al Paciente , Resultado del TratamientoRESUMEN
OBJECTIVES: Ischemic preconditioning (IP) affords resistance to liver ischemia-reperfusion (IR) injury, providing an early phase of protection. Development of delayed IP against IR injury was assessed using partial IR in rat liver. METHODS: The IP manuver (10 minutes of ischemia and up to 72 hours of reperfusion) was induced before 1 hour of ischemia and 20 hours of reperfusion. At the end of the reperfusion period, blood and liver samples were analyzed for serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), haptoglobin and tumor necrosis factor-alpha (TNF-alpha) levels, hepatic histology, protein carbonyl and glutathione (GSH) contents as well as nuclear factor-kappaB (NF-kappaB), and activating protein-1 (AP-1) DNA binding. RESULTS: The IP manuver significantly increased protein carbonyl/GSH ratios (275%), serum ALT (42%), and AST (58%); these changes normalized after 12 hours. Serum AST, ALT, and LDH levels were significantly increased by IR (4-, 5.6-, and 7.0-fold, respectively), with significant changes in liver histology, protein carbonyl/GSH ratio (481% enhancement), and serum TNF-alpha (6.1-fold increase). Delayed IP in IR animals reduced serum AST (66%), ALT (57%), and LDH (90%) and liver GSH depletion (89%), with normalization of protein carbonyl content, serum TNF-alpha levels, and liver histology. Enhanced AP-1/NF-kappaB DNA binding ratios and diminished haptoglobin expression induced by IR were normalized by IP. CONCLUSION: These data support that delayed IP suppresses IR-induced liver injury, oxidative stress, and TNF-alpha response, which coincide with recovery of IR-altered signaling functions represented by normal AP-1/NF-kappaB DNA binding ratios and acute phase responses.
Asunto(s)
Precondicionamiento Isquémico/métodos , Hígado/patología , Daño por Reperfusión/prevención & control , Alanina Transaminasa/sangre , Alanina Transaminasa/metabolismo , Animales , Aspartato Aminotransferasas/sangre , Aspartato Aminotransferasas/metabolismo , Glutatión/metabolismo , Haptoglobinas/metabolismo , Inflamación/prevención & control , L-Lactato Deshidrogenasa/sangre , L-Lactato Deshidrogenasa/metabolismo , Hígado/metabolismo , Hígado/fisiopatología , Masculino , FN-kappa B/genética , FN-kappa B/metabolismo , Estrés Oxidativo/fisiología , Ratas , Ratas Sprague-Dawley , Factor de Transcripción AP-1/metabolismoRESUMEN
We studied the role of Kupffer cell functioning in T3 liver preconditioning against ischemia-reperfusion (IR) injury using the macrophage inactivator gadolinium chloride (GdCl3) previous to T3 treatment. Male Sprague-Dawley rats given a single i.p. dose of 0.1 mg T3/kg were subjected to 1 h ischemia followed by 20 h reperfusion, in groups of animals pretreated with 10 mg GdCl3/kg i.v. 72 h before T(3) or with the respective vehicles. IR resulted in significant enhancement of serum aspartate aminotransferase (3.3-fold increase) and tumor necrosis factor-alpha (93% increase) levels, development of liver damage, and diminished nuclear factor-kappaB DNA binding over control values. These changes, which were suppressed by the T3 administration prior to IR, persisted in animals given GdCl3 before T3 treatment, under conditions of complete elimination of ED2+ Kupffer cells achieved in a time window of 72 h. It is concluded that Kupffer cell functioning is essential for T3 liver preconditioning, assessed in a warm IR injury model by hepatic macrophage inactivation.
Asunto(s)
Precondicionamiento Isquémico , Macrófagos del Hígado/fisiología , Hígado/efectos de los fármacos , Hígado/fisiopatología , Daño por Reperfusión/fisiopatología , Triyodotironina/farmacología , Animales , Antiinflamatorios/farmacología , Aspartato Aminotransferasas/sangre , ADN/metabolismo , Gadolinio/farmacología , Hígado/citología , Hígado/metabolismo , Masculino , FN-kappa B/metabolismo , Ratas , Ratas Sprague-Dawley , Factor de Necrosis Tumoral alfa/sangreRESUMEN
beta 2-Glycoprotein I (beta 2 GPI) is known to influence macrophage uptake of particles with phosphatidylserine containing surfaces, as apoptotic thymocytes and unilamellar vesicles in vitro. Nevertheless, effects upon macrophage activation induced by this interaction are still unknown. beta 2 GPI influence upon the reactive species production by Kupffer cells was evaluated in order to investigate whether beta 2 GPI modulates the macrophage response to negatively charged surfaces. Chemiluminescence of isolated non-parenchymal rat liver cells was measured after phagocytosis of opsonized zymosan or phorbolymristate acetate (PMA) stimulation, in the presence and absence of large unilamellar vesicles (LUVs) containing 25 mol% phosphatidylserine (PS) or 50 mol% cardiolipin (CL) and complementary molar ratio of phosphatidylcholine (PC). beta 2 GPI decreased by 50% the chemiluminescence response induced by opsonized zymosan, with a 66% reduction of the initial light emission rate. PMA stimulated Kupffer cell chemiluminescence was insensitive to human or rat beta 2 GPI. Albumin (500 micrograms/ml) showed no effect upon chemiluminescence. beta 2 GPI increased PS/PC LUV uptake and degradation by Kupffer cells in a concentration-dependent manner, without leakage of the internal contents of the LUVs, as shown by fluorescence intensity enhancement. LUVs opsonized with antiphospholipid antibodies (aPL) from syphilitic patients increased light emission by Kupffer cells. Addition of beta 2 GPI to the assay reduced chemiluminescence due to opsonization with purified IgG antibodies from systemic lupus erythematosus (SLE or syphilis (Sy) patient sera. A marked net increase in chemiluminescence is observed in the presence of Sy aPL antibodies, whereas a decrease was found when SLE aPL were added to the assay, in the presence or absence of beta 2 GPI. At a concentration of 125 micrograms/ml, beta 2 GPI significantly reduced Kupffer cell Candida albicans phagocytosis index and killing score by 50 and 10%, respectively. The present data strongly suggest that particle uptake in the presence of beta 2 GPI is coupled to an inhibition of reactive species production by liver macrophages during the respiratory burst, supporting the role of beta 2 GPI as a mediator of senescent cell removal.
Asunto(s)
Endocitosis/efectos de los fármacos , Glicoproteínas/farmacología , Macrófagos del Hígado/efectos de los fármacos , Hígado/efectos de los fármacos , Animales , Apolipoproteínas/farmacología , Hígado/citología , Mediciones Luminiscentes , Activación de Macrófagos/efectos de los fármacos , Macrófagos Alveolares/efectos de los fármacos , Macrófagos Alveolares/metabolismo , Masculino , Oxidación-Reducción , Estrés Oxidativo/efectos de los fármacos , Fagocitos/efectos de los fármacos , Fosfatidilserinas/metabolismo , Ratas , Ratas Sprague-Dawley , Especies Reactivas de Oxígeno/metabolismo , Estallido Respiratorio , beta 2 Glicoproteína IRESUMEN
OBJECTIVES: Kupffer cells, liver macrophages involved in immunomodulation, phagocytosis, and biochemical attack, can induce cytotoxicity and inflammation when their activity is exacerbated. The aim of this study was to evaluate the effects of C-phycocyanin on Kupffer cell functioning considering its antioxidant and anti-inflammatory properties. MATERIALS AND METHODS: Actions of C-phycocyanin on colloidal carbon phagocytosis, carbon-induced respiratory burst activity, and sinusoidal lactate dehydrogenase (LDH) release were studied in isolated perfused mouse liver. The influence of C-phycocyanin on tumor necrosis factor-a (TNF-alpha) and nitrite levels in serum and liver nitric oxide synthase (NOS) activity was assessed in rats subjected to thyroid hormone (T3) administration, a condition known to underlie hepatic oxidative stress comprising an increased Kupffer cell activity. RESULTS: C-phycocyanin elicited a concentration-dependent inhibition of carbon phagocytosis and carbon-induced O2 uptake (IC50 = 0.2 mg/ml) by perfused livers, with a 52% diminution in the carbon-induced sinusoidal release of LDH being found at a concentration of 0.25 mg/ml. Thyroid calorigenesis induced an 82-fold increase in serum TNF-alpha levels, an effect that was suppressed by pretreatment with C-phycocyanin, the antioxidant alpha-tocopherol, and by the Kupffer cell inactivator gadolinium chloride. C-phycocyanin also suppressed the T3-induced increases in serum nitrite levels (234%) and in the activity of hepatic NOS (75%). CONCLUSIONS: C-phycocyanin significantly decreases Kupffer cell phagocytosis and the associated respiratory burst activity, effects that may contribute to the abolition of oxidative stress-induced TNF-alpha response and NO production by hyperthyroid state.
Asunto(s)
Hepatocitos/metabolismo , Macrófagos del Hígado/metabolismo , Hígado/metabolismo , Estrés Oxidativo/efectos de los fármacos , Ficocianina/farmacología , Animales , Carbono/metabolismo , Ensayo de Inmunoadsorción Enzimática , Hepatocitos/efectos de los fármacos , Técnicas In Vitro , Macrófagos del Hígado/efectos de los fármacos , L-Lactato Deshidrogenasa/metabolismo , Hígado/efectos de los fármacos , Ratones , Óxido Nítrico Sintasa/metabolismo , Nitritos/sangre , Consumo de Oxígeno/efectos de los fármacos , Ratas , Estallido Respiratorio/efectos de los fármacos , Triyodotironina/farmacología , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
The involvement of cytosolic nitric oxide (NO) and mitochondrial superoxide radical (O2(.-)) production was evaluated as a mechanism triggering liver oxidative stress in lindane (40 mg/kg) or L-3,3',5-triiodothyronine (T3, 0.1 mg/kg for 2 consecutive days) treated animals (male Sprague-Dawley rats) subjected to iron overload (200 mg/kg). Lindane and iron led to 504 and 210% increases in the content of hepatic protein carbonyls as an index of oxidative stress, with a 706% enhancement being produced by their combined administration. T3 did not alter this parameter, whereas iron overload increased the content of protein carbonyls by 116% in hyperthyroid rats. Lindane increased NO generation by 106% without changes in generation of O2(.-), whereas iron enhanced both parameters by 109 and 80% over control values, respectively, with a net 33 and 46% decrease, respectively, being elicited by the combined treatment related to iron overload alone. Hyperthyroidism increased liver NO (69%) and O2(.-) (110%) generation compared to controls, effects that were either synergistically augmented or suppressed by iron overload, respectively. The in vitro addition of iron (1 micromol/mg protein) to liver cytosolic fractions from euthyroid (97%) and hyperthyroid (173%) rats also enhanced NO generation. The effects of iron overload on mitochondrial O2(.-) production by hyperthyroid rats were reproduced by the in vitro addition of 1 micromol iron/mg protein and abolished by the in vivo pretreatment with the iron chelator desferrioxamine (500 mg/kg). It is concluded that liver oxidative stress induced by iron overload is independent of NO and O2(.-) production in lindane-treated rats, whereas in hyperthyroid animals NO generation is a major factor contributing to this redox imbalance.
Asunto(s)
Hexaclorociclohexano/toxicidad , Hierro/farmacología , Hígado/efectos de los fármacos , Óxido Nítrico/metabolismo , Superóxidos/metabolismo , Hormonas Tiroideas/toxicidad , Animales , Hígado/metabolismo , Masculino , Óxido Nítrico Sintasa/metabolismo , Óxido Nítrico Sintasa de Tipo II , Estrés Oxidativo/efectos de los fármacos , Ratas , Ratas Sprague-DawleyRESUMEN
Parameters related to liver oxidative stress, Kupffer cell function, and hepatocellular injury were assessed in control rats and in animals subjected to lindane (40 mg/kg; 24 h) and/or iron (200 mg/kg; 4 h) administration. Independently of lindane treatment, iron overload enhanced the levels of iron in serum and liver. Biliary efflux of glutathione disulfide increased by 140, 160, or 335% by lindane, iron, or their combined administration, respectively, and the hepatic content of protein carbonyls was elevated by 5.84-, 2.95-, and 10-fold. Colloidal carbon uptake by perfused livers was not modified by lindane and/or iron, whereas gadolinium chloride (GdCl(3)) pretreatment diminished uptake by 60-72%. Carbon-induced liver O(2) uptake was not altered by lindane, whereas iron produced a 61% increase and the combined treatment led to a 72% decrease over control values. Pretreatment with GdCl(3) abolished these effects in all groups. Lindane-treated rats showed acidophilic hepatocytes in periportal areas and some hepatic cells with nuclear pyknosis, whereas iron overload led to moderate hyperplasia and hypertrophy of Kupffer cells and moderate inflammatory cell infiltration. Combined lindane-iron treatment led to hepatocytes with pyknotic nuclei, significant acidophilia, and extensive lymphatic and neutrophil infiltration in the portal space. Hepatic myeloperoxidase activity increased by 1.1-, 2.1-, or 6.7-fold by lindane, iron, or their combined administration, respectively. Liver sinusoidal lactate dehydrogenase efflux increased by 2.2-fold (basal conditions) and 9.7-fold (carbon infusion) in the lindane-iron treated rats, effects that were diminished by 35 and 78% by GdCl(3) pretreatment, respectively. These data support the contention that lindane sensitizes the liver to the damaging effects of iron overload by providing an added enhancement to the oxidative stress status in the tissue, and this may contribute to the alteration of the respiratory activity of Kupffer cells and the development of an inflammatory response.
Asunto(s)
Enfermedad Hepática Inducida por Sustancias y Drogas/patología , Hexaclorociclohexano/toxicidad , Insecticidas/toxicidad , Sobrecarga de Hierro/patología , Macrófagos del Hígado/efectos de los fármacos , Estrés Oxidativo/fisiología , Animales , Carbono/farmacología , Hierro/metabolismo , Hierro/farmacocinética , Sobrecarga de Hierro/metabolismo , L-Lactato Deshidrogenasa/metabolismo , Hígado/efectos de los fármacos , Hígado/enzimología , Hígado/metabolismo , Masculino , Peroxidasa/metabolismo , Fagocitosis/efectos de los fármacos , Ratas , Ratas Sprague-DawleyRESUMEN
To assess the effect of chronic ethanol ingestion in the content of the reduced forms of coenzymes Q9 (ubiquinol-9) and Q10 (ubiquinol-10) as a factor contributing to oxidative stress in liver and brain, male Wistar rats were fed ad libitum a basal diet containing either 10 or 2.5 mg alpha-tocopherol/100 g diet (controls), or the same basal diet plus a 32% ethanol-25% sucrose solution. After three months treatment, ethanol chronically-treated rats showed identical growth rates to the isocalorically pair-fed controls, irrespectively of alpha-tocopherol dietary level. Lowering dietary alpha-tocopherol led to a decreased content of this vitamin in the liver and brain of control rats, without changes in that of ubiquinol-9, and increased levels of hepatic ubiquinol-10 and total glutathione (tGSH), accompanied by a decrease in brain tGSH. At the two levels of dietary alpha-tocopherol, ethanol treatment significantly decreased the content of hepatic alpha-tocopherol and ubiquinols 9 and 10. This effect was significantly greater at 10 mg alpha-tocopherol/100 g diet than at 2.5, whereas those of tGSH were significantly elevated by 43% and 9%, respectively. Chronic ethanol intake did not alter the content of brain alpha-tocopherol and tGSH, whereas those of ubiquinol-9 were significantly lowered by 20% and 14% in rats subjected to 10 and 2.5 mg alpha-tocopherol/100 g diet, respectively. It is concluded that chronic ethanol intake at two levels of dietary alpha-tocopherol induces a depletion of hepatic alpha-tocopherol and ubiquinols 9 and 10, thus contributing to ethanol-induced oxidative stress in the liver tissue. This effect of ethanol is dependent upon the dietary level of alpha-tocopherol, involves a compensatory enhancement in hepatic tGSH availability, and is not observed in the brain tissue, probably due to its limited capacity for ethanol biotransformation and glutathione synthesis.
Asunto(s)
Encéfalo/efectos de los fármacos , Etanol/administración & dosificación , Hígado/efectos de los fármacos , Ubiquinona/análogos & derivados , Ubiquinona/metabolismo , Vitamina E/administración & dosificación , Animales , Encéfalo/metabolismo , Dieta , Glutatión/metabolismo , Hígado/metabolismo , Masculino , Oxidación-Reducción , Estrés Oxidativo , Ratas , Ratas WistarRESUMEN
Cardiovascular disease (CVD) is the leading cause of death in older women in industrialised countries. It has been suggested that it is the cessation of estrogen production by the ovaries that puts postmenopausal women at increased risk of CVD. Estrogen therapy has demonstrated a protective effect against CVD and several reports suggest that diverse mechanisms may be involved. Oral estrogen appears to be associated with a better lipid profile than the use of transdermal estrogens; however, it is assumed that estrogens, oral and non-oral, have direct actions on the blood vessels that may exert an important role in cardiovascular disease prevention. To investigate the effect of transdermal estrogen therapy on aorta atherogenesis, we studied 20 cholesterol-fed New Zealand White rabbits for 4 months. The rabbits were oophorectomized and randomly assigned to two groups. Ten rabbits underwent bilateral ovariectomy followed by treatment with transdermal 17-beta-estradiol (group E) and the other 10 received placebo after sterilization (Group C). After diet total levels of cholesterol increase in group C from 50. 0+/-12.5 to 820.9+/-186.0 mg/dl, and in group E from 52.6+/-9.4 to 811.4+/-213.0 mg/dl (no significant differences were observed between groups). Estrogen therapy increased twofold the total reactive antioxidant potential (TRAP group C: 22.5+/-16.7 mmol of Trolox/l vs. TRAP group E: 43.4+/-22.4 mmol of Trolox/l; P<0.04). At 4 months, the cholesterol-rich diet caused atherosclerotic lesions in both treated and untreated rabbits affecting 18.7+/-14.5 and 21. 6+/-9.7% of the aortic surface respectively. In summary, the principal result from this study was that although treatment with transdermal 17-beta-estradiol in cholesterol-fed ovariectomized rabbits increases the TRAP to pre-surgery values, it does not inhibit aortic cholesterol accumulation.
Asunto(s)
Enfermedades de la Aorta/tratamiento farmacológico , Arteriosclerosis/tratamiento farmacológico , Arteriosclerosis/patología , Colesterol en la Dieta/administración & dosificación , Estradiol/uso terapéutico , Ovariectomía , Administración Cutánea , Animales , Colesterol en la Dieta/farmacología , Progresión de la Enfermedad , Femenino , Conejos , Insuficiencia del TratamientoRESUMEN
BACKGROUND: The effect of bromoethylamine (BEA) administration on lipid peroxidation and on the activities of antioxidant enzymes was studied. METHODS: Adult rats received BEA at 1.2 mmol/kg, a dose that produces renal papillary necrosis. Lipid peroxidation assessed by maximal rate in MDA formation, the activities of catalase, superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and the levels of non-protein sulfhydryls (NPSH) were measured in renal cortex and papilla of control and BEA-treated animals. RESULTS: After BEA treatment, an increment in lipid peroxidation in papilla and cortex was found after 1.5 and 24 hours of treatment. Catalase activity decreased in both regions, but earlier in cortex. CONCLUSION: These data suggest some role of oxidative stress in the mechanism of BEA-induced papillary necrosis.
Asunto(s)
Antioxidantes/metabolismo , Catalasa/metabolismo , Etilaminas/toxicidad , Glutatión Peroxidasa/metabolismo , Necrosis Papilar Renal/inducido químicamente , Peroxidación de Lípido , Superóxido Dismutasa/metabolismo , Animales , Femenino , Corteza Renal/enzimología , Médula Renal/enzimología , Necrosis Papilar Renal/enzimología , Malondialdehído/análisis , Especificidad de Órganos , Estrés Oxidativo , Ratas , Ratas Sprague-Dawley , Compuestos de Sulfhidrilo/análisisRESUMEN
Liver microsomal functions related to xenobiotic biotransformation and free radical production were studied in control rats and in animals subjected to L-3,3',5-triiodothyronine (T3) and/or lindane administration as possible mechanisms contributing to oxidative stress, in relation to the activity of enzymes (superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), and glucose-6-phosphate dehydrogenase (G-6PDH)) and content of lipid-soluble vitamins (alpha-tocopherol, beta-carotene, and lycopene) affording antioxidant protection. Lindane treatment in euthyroid rats at a dosage of 20mg/kg did not modify the content of liver microsomal cytochromes P450 and b5, the activity of NADPH-cytochrome P450 reductase and NADH-cytochrome b5 reductase, and the production of superoxide radical (O2.-), as well as antioxidant systems, except for the reduction in lycopene levels. Hyperthyroidism elicited a calorigenic response and increased specific and molecular activities of NADPH-cytochrome P450 reductase, O2.- generation, and G-6PDH activity, concomitantly with diminution in liver SOD and catalase activities and in alpha-tocopherol, beta-carotene, and lycopene levels. The administration of lindane to hyperthyroid animals led to a further increase in the molecular activity of NADPH-cytochrome P450 reductase and in the O2.- production/SOD activity ratio, and decrease of hepatic alpha-tocopherol content, in a magnitude exceeding the sum of effects elicited by the separate treatments, as previously reported for reduced glutathione depletion. Collectively, these data support the contention that the increased susceptibility of the liver to the toxic effects of acute lindane treatment in hyperthyroid state is conditioned by potentiation of the hepatic oxidative stress status.
Asunto(s)
Antioxidantes/metabolismo , Hexaclorociclohexano/farmacología , Hipertiroidismo/metabolismo , Microsomas Hepáticos/metabolismo , Estrés Oxidativo , Animales , Biotransformación , Carotenoides/metabolismo , Catalasa/efectos de los fármacos , Catalasa/metabolismo , Sistema Enzimático del Citocromo P-450/efectos de los fármacos , Sistema Enzimático del Citocromo P-450/metabolismo , Glucosafosfato Deshidrogenasa/efectos de los fármacos , Glucosafosfato Deshidrogenasa/metabolismo , Glutatión Peroxidasa/efectos de los fármacos , Glutatión Peroxidasa/metabolismo , Hipertiroidismo/tratamiento farmacológico , Licopeno , Masculino , Microsomas Hepáticos/efectos de los fármacos , NADH NADPH Oxidorreductasas/efectos de los fármacos , NADH NADPH Oxidorreductasas/metabolismo , NADPH-Ferrihemoproteína Reductasa , Ratas , Ratas Sprague-Dawley , Especies Reactivas de Oxígeno/metabolismo , Superóxido Dismutasa/efectos de los fármacos , Superóxido Dismutasa/metabolismo , Triyodotironina/farmacología , Vitamina E/metabolismo , beta Caroteno/metabolismoRESUMEN
1. Twenty-four hours after lindane exposure (5-60 mg/kg) a dose-dependent increase in the serum and hepatic levels of the insecticide was observed. Both the basal rate of O2 consumption and the sinusoidal efflux of lactate dehydrogenase (LDH) by the perfused rat liver was enhanced after the administration of 20-60 mg lindane/kg. 2. The administration of low doses of lindane (5-20 mg/kg) increased carbon uptake and the carbon-induced O2 consumption by the perfused liver, effects that were abolished by pretreatment with the Kupffer cell inactivator gadolinium chloride (GdCl3). These parameters were not modified at the higher doses of lindane used (40-60 mg/kg). 3. In the dose range of 20-60 mg lindane/kg, carbon infusion led to a further increase in liver LDH efflux over values found in its absence, an effect that was markedly diminished by GdCl3 in rat treated with 20 mg lindane/kg, being unaltered by GdCl3 in animals given 60 mg/kg. 4. It is concluded that lindane induces a dose-dependent biphasic effect on Kupffer cell function, which could be conditioned by differential membrane perturbation actions of the insecticide that progressively accumulates in the liver, thus altering receptor-mediated and enzymatic processes related to colloidal carbon phagocytosis. Increased Kupffer cell function at low doses of lindane leads to enhanced liver injury. However, this feature of lindane intoxication at higher doses (60 mg/kg) is independent of Kupffer cell activity and seems to be determined by an oxidative stress mechanism induced at the parenchymal cell level.
Asunto(s)
Hexaclorociclohexano/toxicidad , Insecticidas/toxicidad , Macrófagos del Hígado/efectos de los fármacos , Hígado/citología , Animales , Antiinflamatorios/farmacología , Relación Dosis-Respuesta a Droga , Gadolinio/farmacología , Macrófagos del Hígado/metabolismo , L-Lactato Deshidrogenasa/efectos de los fármacos , L-Lactato Deshidrogenasa/metabolismo , Hígado/efectos de los fármacos , Hígado/metabolismo , Oxígeno/metabolismo , Perfusión , Fagocitosis/efectos de los fármacos , Ratas , Ratas Sprague-DawleyRESUMEN
The effect of several aliphatic aldehydes on lipid peroxidation was evaluated by measuring the oxygen uptake rate, thiobarbituric acid-reactive products formation and the emitted visible chemiluminescence intensity. Measurements were carried out in brain homogenates and erythrocyte plasma membrane and liver microsomal fractions. In all systems studied, aldehydes (25 mmol/L) (e.g. acetaldehyde, 2,2-dimethylpropanal), increased the intensity of the luminescence associated with the oxidation process. In contrast, aldehyde incorporation decreased TBARS production and the rate of oxygen uptake. The increased luminescence intensity is explained in terms of secondary reactions of aldehyde derived free radicals. These results clearly indicate that extreme care must be exercised in the interpretation of chemiluminescence data in the presence of aldehydes.
Asunto(s)
Aldehídos/farmacología , Encéfalo/metabolismo , Membrana Eritrocítica/metabolismo , Peroxidación de Lípido/efectos de los fármacos , Estrés Oxidativo , Animales , Encéfalo/efectos de los fármacos , Membrana Eritrocítica/efectos de los fármacos , Mediciones Luminiscentes , Masculino , Consumo de Oxígeno , Polarografía/métodos , Ratas , Ratas Wistar , Reproducibilidad de los Resultados , Conteo por Cintilación/métodos , Sensibilidad y Especificidad , Sustancias Reactivas al Ácido Tiobarbitúrico/análisisRESUMEN
The influence of thyroid hormone (L-3, 3', 5-triiodothyronine, T3) on Kupffer cell function was studied in the isolated perfused rat liver by colloidal carbon infusion. Rates of carbon uptake were determined from the influent minus effluent concentration difference and the flow rate, and the respective carbon-induced respiratory activity was calculated by integration of the area under the O2 curves during carbon infusion. In the concentration range of 0.2 to 2.0 mg of carbon/ml, livers from euthyroid rats exhibited a sigmoidal-type kinetics of carbon uptake, with a Vmax of 4.8 mg/g liver/min and a concentration of 0.82 mg/ml for half-maximal rate; carbon-induced O2 uptake presented a hyperbolic-type kinetics, with a Vmax of 4.57 mumol of O2/g liver and a K(m) of 0.74 mg of carbon/ml, which significantly correlates with the carbon uptake rates. Light-microscopy showed that carbon was taken up exclusively by non-parenchymal cells, predominantly by Kupffer cells. Thyroid calorigenesis was found in parallel with increased rates of hepatic O2 consumption and thiobarbituric acid reactive substances (TBARS) formation, glutathione (GSH) depletion, and higher sinusoidal lactate dehydrogenase (LDH) efflux compared to control values. In the concentration range of 0.25 to 0.75 mg/ml, carbon infusion did not modify liver LDH efflux in control rats, while it was significantly enhanced in T3-treated animals. In this latter group, higher carbon concentrations (1 and 1.3 mg/ml) led to loss of viability of the liver. At 0.25 to 0.75 mg of carbon/ml, both the rates of carbon uptake and the associated carbon-induced respiratory activities were significantly increased by T3 treatment, effects that were abolished by pretreatment of the rats with gadolinium chloride (GdCl3). In addition, GdCl3 decreased by 50% the changes induced by T3 in hepatic GSH content and TBARS formation. It is concluded that hyperthyroidism enhances Kupffer cell function, correlated with the increased number of liver macrophages observed histologically, which may represent an alternate source of reactive O2 species to that induced in parenchymal cells, thus contributing to the enhanced oxidative stress status developed.