Quercetin ameliorates glucose and lipid metabolism and improves antioxidant status in postnatally monosodium glutamate-induced metabolic alterations

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Growth hormone and heart failure: Oxidative stress and energetic metabolism in rats

Several evidences point for beneficial effects of growth hormone (GH) in heart failure (HF). Taking into account that HF is related with changes in myocardial oxidative stress and in energy generation from metabolic pathways, it is important to clarify whether GH increase or decrease myocardial oxidative stress and what is its effect on energetic metabolism in HF condition. Thus, this study investigated the effects of two different doses of GH on energetic metabolism and oxidative stress in myocardium of rats with HF. Male Wistar rats (n = 25) were submitted to aortic stenosis (AS). The HF was evidenced by tachypnea and echocardiographic criteria around 28 weeks of AS. The rats were then randomly divided into three groups: (HF) with HF, treated with saline (0.9% NaCl); (HF-GHI), treated with 1 mk/kg/day recombinant human growth hormone (rhGH), and (HF-GH2) treated with 2 mg/kg/day rhGH. GH was injected, subcutaneously, daily for 2 weeks. A control group (sham; n = 12), with the same age of the others rats was evaluated to confirm data for AS. HF had lower IGF-I (insulin-like growth factor-I) than sham-operated rats, and both GH treatments normalized IGF-I level. HF-GH1 animals had lower lipid hydroperoxide (LH), LH/total antioxidant substances (TAS) and glutathione-reductase than HF. Glutathione peroxidase (GSH-Px), hydroxyacyl coenzyme-A dehydrogenase, lactate dehydrogenase(LDH) were higher in HF-GH1 than in HF. HF-GH2 compared with HF, had increased LH/TAS ratio, as well as decreased oxidized glutathione and LDH activity. Comparing the two GH doses, GSH-Px, superoxide dismutase and LDH were lower in HF-GH2 than in HF-GHI. In conclusion, GH effects were dose-dependent and both tested doses did not aggravate the heart dysfunction. The higher GH dose, 2 mg/kg exerted detrimental effects related to energy metabolism and oxidative stress. The lower dose, 1 mg/kg GH exerted beneficial effects enhancing antioxidant defences, reducing oxidative stress and improving energy generation in myocardium of rats with heart failure. (c) 2007 Elsevier Ltd. All rights reserved.

Diet compounds, glycemic index and obesity-related cardiac effects

Background: Diet compounds may influence obesity-related cardiac oxidative stress and metabolic sifting. Carbohydrate-rich diet may be disadvantageous from fat-rich diet to cardiac tissue and glycemic index rather than lipid profile may predict the obesity-related cardiac effects.Materials and methods: Male Wistar rats were divided into three groups (n=8/group): (C) receiving standard chow (3.0 kcal/g); (CRD) receiving carbohydrate-rich diet (4.0 kcal/g), and (FRD) receiving fat-rich diet (4.0 kcal/g). Rats were sacrificed after the oral glucose tolerance test (OGTT) at 60 days of dietary treatments. Lipid profile and oxidative stress parameters were determined in serum. Myocardial samples were used to determine oxidative stress, metabolic enzymes, glycogen and triacylglycerol.Results: FRD rats showed higher final body weight and body mass index than CRD and C. Serum cholesterol and low-density lipoprotein were higher in FRD than in CRD, while triacylglycerol and oxidized low-density lipoprotein cholesterol were higher in CRD than in FRD. CRD rats had the highest myocardial lipid hydroperoxide and diminished superoxide dismutase and catalase activities. Myocardial glycogen was lower and triacylglycerol was higher in CRD than in C and FRD rats. Although FRD rats had depressed myocardial-reducing power, no significant changes were observed in myocardial energy metabolism. Myocardial beta-hydroxyacyl coenzyme-A dehydrogenase and citrate synthase, as well as the enhanced lactate debydrogenase/citrate synthase ratio indicated that fatty acid degradation was decreased in CRD rats. Glycemic index was positively correlated with obesity-related cardiac effects.Conclusions: Isoenergetic carbohydrate-rich and fat-rich diets induced different degree of obesity and differently affected lipid profile. Carbohydrate-rich diet was deleterious relative to fat-rich diet in the heart enhancing lipoperoxidation and shifting the metabolic pathway for energy production. Glycemic index rather than dyslipidemic profile may predict the obesity effects on cardiac tissue. (C) 2007 Elsevier B.V. All rights reserved.

Growth and photosynthetic down-regulation in Coffea arabica in response to restricted root volume

Coffee (Coffea arabica L.) plants were grown in small (3-L), medium (10-L) and large (24-L) pots for 115 or 165 d after transplanting (DAT), which allowed different degrees of root restriction. Effects of altered source : sink ratio were evaluated in order to explore possible stomatal and non-stomatal mechanisms of photosynthetic down-regulation. Increasing root restriction brought about large and general reductions in plant growth associated with a rising root : shoot ratio. Treatments did not affect leaf water potential or leaf nutrient status, with the exception of N content, which dropped significantly with increasing root restriction even though an adequate N supply was available. Photosynthesis was severely reduced when plants were grown in small pots; this was largely associated with non-stomatal factors, such as decreased Rubisco activity. At 165DAT contents of hexose, sucrose, and amino acids decreased in plants grown in smaller pots, while those of starch and hexose-P increased in plants grown in smaller pots. Photosynthetic rates were negatively correlated with the ratio of hexose to free amino acids, but not with hexose content. Activities of acid invertase, sucrose synthase, sucrose-P synthase, fructose-1,6- bisphosphatase, ADP-glucose pyrophosphorylase, starch phosphorylase, glyceraldehyde-3-P dehydrogenase, PPi : fructose-6-P 1-phosphotransferase and NADP : glyceraldehyde-3-P dehydrogenase all decreased with severe root restriction. Glycerate-3-P : Pi and glucose-6-P : fructose-6-P ratios decreased accordingly. Photosynthetic down-regulation was unlikely to have been associated directly with an end-product limitation, but rather with decreases in Rubisco. Such a down-regulation was largely a result of N deficiency caused by growing coffee plants in small pots.

Variabilidade isoenzimática em oito raças de milho

Com o objetivo de avaliar a variabilidade genética e as relações de afinidade entre dezenove populações de oito raças de milho (Zea mays L.) - as comerciais antigas Cateto Sulino, Cateto Sulino Grosso, Cateto Nortista e Canario de Ocho, e as raças indígenas Moroti, Lenha, Entrelaçado e Caingang - analisaram-se os seguintes sistemas enzimáticos: glutamato oxalacetato transaminase (GOT), esterase (EST) e malato desidrogenase (MDH). Observou-se maior semelhança entre as raças pertencentes a um mesmo grupo, mas as populações analisadas não se agruparam de acordo com as raças, classificadas anteriormente segundo caracteres morfológicos. Os sistemas enzimáticos utilizados não permitiram a caracterização individual de cada uma das raças analisadas. As indígenas apresentaram maior variabilidade do que as comerciais antigas quanto ao número de alelos por loco e à porcentagem de locos polimórficos.

Identification of suitable internal control genes for expression studies in Coffea arabica under different experimental conditions

Background: Quantitative data from gene expression experiments are often normalized by transcription levels of reference or housekeeping genes. An inherent assumption for their use is that the expression of these genes is highly uniform in living organisms during various phases of development, in different cell types and under diverse environmental conditions. To date, the validation of reference genes in plants has received very little attention and suitable reference genes have not been defined for a great number of crop species including Coffea arabica. The aim of the research reported herein was to compare the relative expression of a set of potential reference genes across different types of tissue/organ samples of coffee. We also validated the expression profiles of the selected reference genes at various stages of development and under a specific biotic stress.Results: The expression levels of five frequently used housekeeping genes (reference genes), namely alcohol dehydrogenase (adh), 14-3-3, polyubiquitin (poly), beta-actin (actin) and glyceraldehyde-3-phosphate dehydrogenase (gapdh) was assessed by quantitative real-time RT-PCR over a set of five tissue/organ samples (root, stem, leaf, flower, and fruits) of Coffea arabica plants. In addition to these commonly used internal controls, three other genes encoding a cysteine proteinase (cys), a caffeine synthase (ccs) and the 60S ribosomal protein L7 (rpl7) were also tested. Their stability and suitability as reference genes were validated by geNorm, NormFinder and BestKeeper programs. The obtained results revealed significantly variable expression levels of all reference genes analyzed, with the exception of gapdh, which showed no significant changes in expression among the investigated experimental conditions.Conclusion: Our data suggests that the expression of housekeeping genes is not completely stable in coffee. Based on our results, gapdh, followed by 14-3-3 and rpl7 were found to be homogeneously expressed and are therefore adequate for normalization purposes, showing equivalent transcript levels in different tissue/ organ samples. Gapdh is therefore the recommended reference gene for measuring gene expression in Coffea arabica. Its use will enable more accurate and reliable normalization of tissue/organ-specific gene expression studies in this important cherry crop plant.

Propolis: Effect of different concentrations, extracts and intake period on seric biochemical variables

Propolis is a resinous substance produced by honeybees that possesses many biological activities, such as antitumor, antioxidant, antimicrobial, anti-inflammatory, and immunomodulatory, among others. The purpose of the present study was to investigate the biochemical profile of propolis-treated rats to observe whether propolis might lead to side effects after administration. Three different treatments were analyzed: (1) rats were treated with different concentrations of propolis (1, 3 and 6 mg/kg/day) during 30 days; (2) rats were treated with I mg/kg/day of ethanolic or water extracts of propolis (EEP, WEP) during 30 days; (3) rats were treated with I mg/kg/day of ethanolic extract of propolis during 90 and 150 days. Our results demonstrated no alterations in the seric levels of cholesterol, HDL-cholesterol, total lipids, triglycerides and in the specific activity of aminotransferases (AST) and lactic dehydrogenase (LDH) of propolis-treated groups when compared to controls. on the basis of our findings, since propolis does not induce any significant change in seric parameters, it is claimed that long-term administration of propolis might not have any cardiac injury. (c) 2005 Elsevier B.V.. All rights reserved.

Influence of Taurine on Cardiac Remodeling Induced by Tobacco Smoke Exposure

Background/Aims: To investigate the effect of taurine on cardiac remodeling induced by smoking. Methods: In the first step, rats were allocated into two groups: Group C (n=14): control; Group T (n=14): treated with taurine (3% in drinking water), for three months. In the second step, rats were allocated into two groups: Group ETS (n=9): rats exposed to tobacco smoke; Group ETS-T (n=9): rats exposed to tobacco smoke and treated with taurine for two months. Results: After three months, taurine presented no effects on morphological or functional variables of normal rats assessed by echocardiogram. on the other hand, after two months, ETS-T group presented higher LV wall thickness (ETS=1.30 (1.20-1.42); ETS-T=1.50 (1.40-1.50); p=0.029), E/A ratio (ETS=1.13 +/- 0.13; ETS-T=1.37 +/- 0.26; p=0.028), and isovolumetric relaxation time normalized for heart rate (ETS=53.9 +/- 4.33; ETS-T=72.5 +/- 12.0; p<0.001). The cardiac activity of the lactate dehydrogenase was higher in the ETS-T group (ETS=204 +/- 14 nmol/mg protein; ETS-T=232 +/- 12 nmol/mg protein; p<0.001). ETS-T group presented lower levels of phospholamban (ETS=1.00 +/- 0.13; ETS-T=0.82 +/- 0.06; p=0.026), phosphorylated phospholamban at Ser16 (ETS=1.00 +/- 0.14;ETS-T=0.63 +/- 0.10;p=0.003), and phosphorylated phosfolamban/phospholamban ratio (ETS=1.01 +/- 0.17; ETS-T=0.77 +/- 0.11; p=0.050). Conclusion: In normal rats, taurine produces no effects on cardiac morphological or functional variables. on the other hand, in rats exposed to cigarette smoke, taurine supplementation increases wall thickness and worsens diastolic function, associated with alterations in calcium handling protein and cardiac energy metabolism. Copyright (C) 2011 S. Karger AG, Basel

Ventricular Remodeling Induced by Tissue Vitamin A Deficiency in Rats

Background/Aims: Experimental studies suggest that vitamin A plays a role in regulating cardiac structure and function. We tested the hypothesis that cardiac vitamin A deficiency is associated with adverse myocardial remodeling in young adult rats. Methods: Two groups of young female rats, control (C - n = 29) and tissue vitamin A deficient (RVA - n = 31), were subjected to transthoracic echocardiography exam, isolated rat heart study and biochemical study. Results: The RVA rats showed a reduced total vitamin A concentration in both the liver and heart [vitamin A in heart, mu mol/kg (C = 0.95 +/- 0.44 and RVA = 0.24 +/- 0.16, p = 0.01)] with the same serum retinol levels (C = 0.73 +/- 0.29 mu mol/L e RVA = 0.62 +/- 0.17 mu mol/L, p = 0.34). The RVA rats showed higher left ventricular diameters and reduced systolic function. The RVA rats also demonstrated increased lipid hydroperoxide/total antioxidant capacity ratio and cardiac levels of IFN-gamma and TNF-alpha but not of metalloproteinase (MMP)-2 and -9 activity. on the other hand, the RVA rats had decreased levels of beta-hydroxyacylcoenzyme A dehydrogenase and lactate dehydrogenase. Conclusions: Tissue vitamin A deficiency stimulated cardiac remodeling and ventricular dysfunction. Additionally, the data support the involvement of oxidative stress, energy metabolism, and cytokine production in this remodeling process. Copyright (C) 2010 S. Karger AG, Basel

Influence of different doses of retinoic acid on cardiac remodeling

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influence of AIN-93 diet on mortality and cardiac remodeling after myocardial infarction in rats

Background: The AIN-93 diet was proposed by the American Institute of Nutrition with the objective of standardising studies in experimental nutrition. Our objective was to analyze the effects of AIN-93 diet after myocardial infarction in rats.Methods: Post weaning, the animals were divided into two groups: control (C, n=62), fed the standard diet of our laboratory (Labina); AIN-93 Group (n=70), fed the AIN-93 diet. Achieving 250 g, the animals were subjected to myocardial infarction.Results: Early mortality was increased in AIN-93 animals, associated with lower serum levels of calcium, magnesium, potassium, sodium, and phosphorus. on the other hand, after 90 days, AIN-93 showed smaller normalized left ventricular dimensions. The caloric and carbohydrate intake was smaller, but the fat intake was higher in AIN-93 rats. AIN-93 group also showed increased levels of beta-hydroxyacylcoenzyme A dehydrogenase and citrate synthase. In addition, serum levels of insulin and cardiac levels of malondialdehyde, metalloproteinases-2 and -9, and TNF-alpha and IFN-gamma were decreased in the AIN-93 group.Conclusion: AIN-93 diet increased early mortality, while attenuated the chronic remodeling process after experimental coronary occlusion. Therefore, this diet has biological effects and should be use with attention in this model. (C) 2010 Elsevier B.V. All rights reserved.

Ischaemia and reperfusion effects on skeletal muscle tissue: morphological and histochemical studies

This was a study on the oxidative stress due to ischaemia (I) and reperfusion (R) in skeletal muscle tissue. Using a tourniquet, groups of rats were submitted to ischaemia for 4 h, followed by different reperfusion periods. The animals were divided in four groups: control; 4 h of ischaemia (IR); 4 h of ischaemia plus 1 h reperfusion (IR-1 h); 4 h of ischaemia plus 24 h reperfusion (IR-24 h); and 4 h of ischaemia plus 72 h reperfusion (IR-72 h). At the end of the procedures, samples of soleus muscle were collected and frozen in n-hexane at -70 degrees C. Cryostat sections were submitted to haematoxylin-eosin, succinate dehydrogenase (SDH) and nicotinamide adenine dinucleotide-tetrazolium reductase (NADH-TR) stains. An additional muscle sample was processed for electron microscopy. No alterations were found in control animals. IR group showed fibres had normal aspect besides some round, acidophilic and hypertrophic fibres. There were several fibres with angular outlines and smaller diameters in this group compared with control group. NADH-TR/SDH reaction was moderately intense in most fibres. In some fibres, cytoplasm showed areas without activity and other fibres had very intense reactivity. IR-1 h group showed oedema hypercontracted fibres with disorganized myofibrils, mitochondria with focal lesions and dilated sarcoplasmic reticulum. NADH-TR/SDH reaction was moderate to weak. IR-24 h showed intense inflammatory infiltrate in the endomysium and perimysium. NADH-TR/SDH reaction was similar to IR-1 h. IR-72 h showed necrotic fibres, areas with inflammatory infiltrate, reduced muscle fibres at different stages of necrosis and phagocytosis, and many small round and basophilic fibres characterizing a regeneration process. NADH-TR/SDH reaction was weak to negative. Our results suggest that ischaemia and the subsequent 1-, 24- and 72-h reperfusions induced progressive histological damage. Although progressive, it may be reversible because there were ultrastructural signs of recovery after 72-h reperfusion. This recovery could in part be due to the low oxidative stress identified by the morphological and histochemical analysis.

Locomotor performance of closely related Tropidurus species: relationships with physiological parameters and ecological divergence

Tropidurid lizards have colonized a variety of Brazilian open environments without remarkable morphological variation, despite ecological and structural differences among habitats used. This study focuses on two Tropidurus sister-species that, despite systematic proximity and similar morphology, exhibit great ecological divergence and a third ecologically generalist congeneric species providing an outgroup comparison. We quantified jumping capacity and sprint speed of each species on sand and rock to test whether ecological divergence was also accompanied by differences in locomotor performance. Relevant physiological traits possibly associated with locomotor performance metabolic scopes and fiber type composition, power output and activity of the enzymes citrate synthase, pyruvate kinase and lactate dehydrogenase of the iliofibularis muscle - were also compared among the three Tropidurus species. We found that the two sister-species exhibited remarkable differences in jumping performance, while Tropidurus oreadicus, the more distantly related species, exhibited intermediate values. Tropidurus psamonastes, a species endemic to sand dunes, exhibited high absolute sprint speeds on sand, jumped rarely and possessed a high proportion of glycolytic fibers and low activity of citrate synthase. The sister-species Tropidurus itambere, endemic to rocky outcrops, performed a large number of jumps and achieved lower absolute sprint speed than T. psamonastes. This study provides evidence of rapid divergence of locomotor parameters between sister-species that use different substrates, which is only partially explained by variation in physiological parameters of the iliofibularis muscle.

Mitochondrial DNA polymorphism and heteroplasmy in populations of Aedes aegypti in Brazil

The tropical mosquito Aedes aegypti (Diptera: Culicidae) is the most important domestic vector of urban yellow fever and dengue viruses. Ae. aegypti originated from Africa and was probably introduced into Brazil during the colonial period through embarkations, and dengue epidemics soon followed. Genetic analysis of 12 Ae. aegypti populations from five states in Brazil was conducted based on two mitochondrial DNA fragments: cytochrome oxidase I and NADH dehydrogenase subunit 4. Analyses comparing individual haplotypes indicated the existence of two well-defined clades, probably representing two mitochondrial lineages. Analysis of molecular variance showed significant variability in genetic structure among collections within groups. Mantel regression analysis showed a correlation between genetic and geographic distances, mainly because of northern and northeastern populations, in comparison with those in the southeast. The population from Santos, the largest port in Brazil, showed the greatest diversity, with 10 unique haplotypes, an indication of recent introductions that have not yet spread to other Brazilian cities. Different mitochondrial DNA sequences were found in three specimens, indicating the presence of heteroplasmy.

Maternal undernutrition and the offspring kidney: from fetal to adult life

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)