Antioxidant defense in rat brain regions after developmental lead exposure

Oxidative stress is considered a possible molecular mechanism involved in Pb neurotoxicity. Considering the vulnerability of the developing brain to Pb neurotoxicity, this study was carried out to investigate the effects of low-level developmental Pb exposure on brain regions antioxidant enzymes activities. Wister dams were exposed to 500 ppm of Pb, as Pb acetate, or to 660 ppm Na acetate in the drinking water during pregnancy and lactation. The activities of superoxide dismutase (SOD), glutathione peroxidase and glutathione reductase were determined in the hypothalamus, hippocampus and striatum of male pups at 23 (weaned) or 70 days (adult) of age. In the Pb-exposed 23-day-old pups, the activity of SOD was decreased in the hypothalamus. Regarding adults, there was no significant treatment effect in any of the enzymes and regions evaluated. Based on the present results, it seems that oxidative stress due to decreased antioxidant function may occur in weaned rats but it is suggested that this should not be the main mechanism involved in the neurotoxicity of low-level Pb exposure. (C) 2001 Elsevier B.V. Ireland Ltd. All rights reserved.

Differential morphofunctional characteristics and gene expression in fast and slow muscle of rats with monocrotaline-induced heart failure

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.

Avaliações sensoriais, bioquímicas e microbiológicas do guacamole, um produto à base de abacate, sob armazenamento a frio e com adição de ácido ascórbico

The elaboration of avocado products for commercialization keeping their characteristics of fresh product has been limited. The cut avocado darkens quickly and their sensorial characteristics are modified with the storage. In the present research, the sensorial parameters, microbiological stability, and peroxidase and polyphenoloxidase activity were evaluated in guacamole added with ascorbic acid and conserved under low temperature, by using avocado variety Hass. Products were conditioned in polyethylene+nylon packages with and without vacuum application; then, they were subjected to the slow and fast freezing (-18 degrees C) and stored in freezer (-18 degrees C). Evaluations were performed at the moment of elaboration of the product (t0) and at 3, 7 and 30 days post-storage. At t30, samples were kept under refrigeration (4 +/- 1 degrees C) and evaluated at 3, 5 and 7 days. After the 30 days of storage, -18 degrees C under freezing, followed by thawing and keeping at 4 +/- 1 degrees C for 7 days, the notes for the sensorial parameters decreased. The peroxidase activity was totally inhibited in the elaborated product and the polifenol oxidase activity considerably decreased in the guacamole (20.07 mM catechol/g fresh matter) relative to those in the fruit (58.31 mM catechol/g fresh matter), however with no significant variation during storage (at -18 degrees C). The samples were microbiologically stable under the conditions of the present study. The addition of ascorbic acid contributed to the conservation of the frozen avocado product by decreasing the enzymatic activity. However, the sensorial parameters are prejudiced under thawing and storage at 4 +/- 1 degrees C.

Nitric oxide reduces oxidative stress generated by lactofen in soybean plants

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Pro-oxidant activity of apocynin radical

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

Using Amino Acid Correlation and Community Detection Algorithms to Identify Functional Determinants in Protein Families

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

Antioxidant activity of indigo and its preventive effect against ethanol-induced DNA damage in rat gastric mucosa

Ethanol-induced oxidative damage is commonly associated with the generation of reactive oxygen molecules, leading to oxidative stress. Considering that antioxidant activity is an important mechanism of action involved in cytoprotection, the aim of this work was to evaluate the antioxidant properties of the alkaloid indigo (1) (2 mg/kg, p. o.), obtained from the leaves of Indigofera truxillensis Kunth (Fabaceae), on rat gastric mucosa submitted to ethanol-induced (100%, 1 mL, p.o.) gastric ulcer. Enzymatic assays and DNA fragmentation analysis were performed. When ethanol was administered to the control group, the sulfhydryl content (SH) and the glutathione peroxidase (GPx) activity decreased by 41% and 50%, respectively; in contrast, superoxide dismutase (SOD) and glutathione reductase (GR) activities increased by 56% and 67%, respectively. Additionally, myeloperoxidase (MPO) activity, a marker for free radical generation caused by polymorphonuclear neutrophil (PMN) tissue infiltration, also increased 4.5-fold after ethanol treatment. Rat gastric mucosa exposed to ethanol showed DNA fragmentation. Indigo alkaloid pretreatment protected rats from ethanol-induced gastric lesions. This effect was determined by the ulcerative lesion area (ULA), indicating an inhibition of around 80% at 2 mg/kg. This alkaloid also diminished GPx activity, which was higher than that observed with ethanol alone. However, this effect was counterbalanced by increased GR activity. Indigo was unable to restore alterations in SOD activity promoted by ethanol. After indigo pretreatment, SH levels and MPO activity remained normal and gastric mucosa DNA damage caused by ethanol was also partially prevented by indigo. These results suggest that the gastroprotective mechanisms of indigo include non-enzymatic antioxidant effects and the inhibition of PMN infiltration which, in combination, partially protect the gastric mucosa against ethanol-induced DNA damage.

Oxidative stress biomarkers and aggressive behavior in fish exposed to aquatic cadmium contamination

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Healing, Antioxidant and Cytoprotective Properties of Indigofera truxillensis in Different Models of Gastric Ulcer in Rats

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

Isoenzimatic variability among five peanut cultivars

A variabilidade genética foi avaliada dentro e entre amostras de diferentes cultivares de amendoim, Arachis hypogaea L., conhecidos como Roxo, Tatu Branco, Tatu Vermelho, Tatuí Vermelho e Tatuí (sementes com película branca), fornecidos por fazendas situadas nas regiões dos municípios de Marília, Presidente Prudente e São Manuel. Para tal análise, foi utilizada a técnica de eletroforese horizontal em gel de poliacrilamida, para os sistemas da leucil-aminopeptidase (LAP), aspartato aminotransferase (ATT) e peroxidase (PER). No sistema da leucil-aminopeptidase, foram observadas três bandas enzimáticas, denominadas LAP-A, LAP-B e LAP-C. Os padrões de bandas obtidos para o sistema da aspartato-aminotransferase mostraram a existência de três bandas anódicas, AAT-A, AAT-B e AAT-C. No sistema da peroxidase (PER), foram observadas quinze bandas, sendo oito anódicas (PER-A a PER-H) e sete catódicas (PER-I a PER-P). Os sistemas enzimáticos da peroxidase e leucil-aminopeptidase não foram discriminativos para as amostras analisadas dos diferentes cultivares obtidos nas diversas regiões. O sistema da aspartato-aminotransferase apresentou um padrão composto pelas bandas AAT-B e AAT-C, que se mostrou característico e discriminativo para as amostras do cultivar Tatu Branco, procedente de Presidente Prudente, e do 'Tatuí Vermelho', proveniente de Presidente Prudente e São Manuel.

Tobacco Smoke Induces Ventricular Remodeling Associated with an Increase in NADPH Oxidase Activity

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Cytochemical characterization of eosinophilic leukocytes circulating in the blood of the turtle (Chrysemys dorbignih)

Eosinophils and neutrophils are granulocytic leukocytes that are present in the blood of most vertebrates. Studies have been performed on lower vertebrates to understand the biological roles of the cells in defense mechanisms and to establish phylogenetic studies and new experimental models. Whether these 2 cell types exist in reptiles is a matter of controversy. In the blood of turtles there are 2 types of granulocytes that exhibit eosinophilia, one of them with round cytoplasmic granules and the other with elongated cytoplasmic granules. It has been suggested that these cells may be eosinophils in different stages of maturation but they also may be distinct cell types, i.e. eosinophils and neutrophils. In the present study, we characterized the 2 types of granulocytes that are present in the blood of Chrysemys dorbignih, using cytochemical techniques. Type I eosinophils showed activity of nonspecific esterase, peroxidase activity that is resistant to KCN, and basic proteins. Type II eosinophils exhibited activity of trimetaphosphatase, alkaline phosphatase, nonspecific esterase, peroxidase that is sensitive to KCN, and basic proteins. These observations indicate the existence of 2 distinct cell types in the blood of Chrysemys dorbignih, type I and type II eosinophils, that correspond to eosinophils and heterophils (neutrophils) of mammals and other vertebrates.

S-100 dendritic cells in normal and Dermatobia hominis infested cattle skin

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

Beneficial effects of dietary copper supplementation on serum lipids and antioxidant defenses in rats

Background: A nutrition experiment was utilized to investigate the effects of two levels of dietary copper (Cu) supplementation on lipid profile and antioxidant defenses in serum of rats. Methods: Male Wistar rats (180-200 g; n = 10) were divided into three groups: control group (A), fed a basal diet with 6 mu g Cu/g, and rats fed a basal diet with Cu (CuSO4) supplementation from aqueous solutions, for 4 weeks at the final concentrations of 2 mg Cu/rat (B) and 3 mg Cu/rat (C). Results: No significant changes were observed in final body weight, body weight gain, food consumption, total serum protein and high-density lipoprotein. Cu supplementation reduced the triacylglycerol (TG), total cholesterol and low-density lipoprotein (LDL-C). The LDL-C/TG ratio and total antioxidant substances (TAS) were higher in (B) and (C) groups than in (A) group. There was a positive correlation between Cu supplementation and ceruloplasmin levels. The markers of oxidative stress, lipid hydroperoxide and lipoperoxide were decreased with Cu supplementation. No alterations were observed in superoxide dismutase, indicating saturation of Cu enzyme site. The glutathione peroxidase activities (GSH-Px) were increased in both Cu-supplemented groups. Considering that a copper-selenium interaction can affect mineral availability of both elements, the effects of Cu on TAS and GSH-Px activities were associated with increased selenium disposal. Conclusions: Dietary Cu supplementation had beneficial effects on lipid profile by improving endogenous antioxidant defenses and decreasing the oxidative stress in vivo. Copyright (C) 2005 S. Karger AG, Basel.