Associations between glutathione peroxidase-1 Pro198Leu polymorphism, selenium status, and DNA damage levels in obese women after consumption of Brazil nuts

Objective: Alterations in selenium (Se) status may result in suboptimal amounts of selenoproteins, which have been associated with increased oxidative stress levels. The Pro198Leu polymorphism at the glutathione peroxidase-1 (GPx1) gene is supposed to be functional. The response of Se status, GPx activity, and levels of DNA damage to a Se supplementation trial between the genotypes related to that polymorphism was investigated. Methods: A randomized trial was conducted with 37 morbidly obese women. Participants consumed one Brazil nut, which provided approximately 290 mu g of Se a day, for 8 wk. Blood Se concentrations, erythrocyte GPx activity, and DNA damage levels were measured at baseline and at 8 wk. The results were compared by genotypes. Results: The genotype frequencies were 0.487, 0.378, and 0.135 for Pro/Pro (the wild-type genotype), Pro/Leu, and Leu/Leu, respectively. At baseline, 100% of the subjects were Se deficient, and after the supplementation, there was an improvement in plasma Se (P < 0.001 for Pro/Pro and Pro/Leu, P < 0.05 for Leu/Leu), erythrocyte Se (P = 0.00 for Pro/Pro and Pro/Leu, P < 0.05 for Leu/Leu), and GPx activity (P = 0.00 for Pro/Pro, P < 0.00001 for Pro/Leu, P < 0.001 for Leu/Leu). In addition, the Pro/Pro group showed a decrease in DNA damage after Brazil nut consumption compared with baseline (P < 0.005), and those levels were higher in Leu/Leu subjects compared with those with the wild-type genotype (P < 0.05). Conclusion: Consumption of one unit of Brazil nuts daily effectively increases Se status and increases GPx activity in obese women, regardless of GPx1 Pro198Leu polymorphism. However, the evaluated biomarkers showed distinct results in response to the supplementation when the polymorphism was considered. (c) 2011 Elsevier Inc. All rights reserved.

Influence of a probiotic soy product on fecal microbiota and its association with cardiovascular risk factors in an animal model

Background: Previous work showed that daily ingestion of an aqueous soy extract fermented with Enterococcus faecium CRL 183 and Lactobacillus helveticus 416, supplemented or not with isoflavones, reduced the total cholesterol and non-HDL-cholesterol levels, increased the high-density lipoprotein (HDL) concentration and inhibited the raising of autoantibody against oxidized low-density lipoprotein (ox-LDL Ab) and the development of atherosclerotic lesions. Objective: The aim of this study was to characterize the fecal microbiota in order to investigate the possible correlation between fecal microbiota, serum lipid parameters and atherosclerotic lesion development in rabbits with induced hypercholesterolemia, that ingested the aqueous soy extract fermented with Enterococcus faecium CRL 183 and Lactobacillus helveticus 416. Methods: The rabbits were randomly allocated to five experimental groups (n = 6): control (C), hypercholesterolemic (H), hypercholesterolemic plus unfermented soy product (HUF), hypercholesterolemic plus fermented soy product (HF) and hypercholesterolemic plus isoflavone-supplemented fermented soy product (HIF). Lipid parameters and microbiota composition were analyzed on days 0 and 60 of the treatment and the atherosclerotic lesions were quantified at the end of the experiment. The fecal microbiota was characterized by enumerating the Lactobacillus spp., Bifidobacterium spp., Enterococcus spp., Enterobacteria and Clostridium spp. populations. Results: After 60 days of the experiment, intake of the probiotic soy product was correlated with significant increases (P < 0.05) on Lactobacillus spp., Bifidobacterium spp. and Enterococcus spp. and a decrease in the Enterobacteria population. A strong correlation was observed between microbiota composition and lipid profile. Populations of Enterococcus spp., Lactobacillus spp. and Bifidobacterium spp. were negatively correlated with total cholesterol, non-HDL-cholesterol, autoantibodies against oxidized LDL (ox-LDL Ab) and lesion size. HDL-C levels were positively correlated with Lactobacillus spp., Bifidobacterium spp., and Enterococcus spp. populations. Conclusion: In conclusion, daily ingestion of the probiotic soy product, supplemented or not with isoflavones, may contribute to a beneficial balance of the fecal microbiota and this modulation is associated with an improved cholesterol profile and inhibition of atherosclerotic lesion development.

Mate attenuates DNA damage and carcinogenesis induced by diethylnitrosamine and thermal injury in rat esophagus

Drinking hot mate has been associated with risk for esophageal cancer in South America. Thus. the aims of this study were to evaluate the modifying effects of mate intake on DNA damage and esophageal carcinogenesis induced by diethylnitrosamine (DEN) and thermal injury (TI) in male Wistar rats. At the initiation phase of carcinogenesis, rats were treated with DEN (8 x 80 mg/kg) and submitted to TI (water at 65 degrees C, 1 ml/rat, instilled into the esophagus). Concomitantly, the animals received mate (2.0% w/v) for 8 weeks. Samples of peripheral blood were collected 4 h after the last DEN application for DNA damage analysis. At weeks 8 and 20, samples from esophagus and liver were also collected for histological and immunohistochemical analysis. Mate significantly decreased DNA damage in leukocytes, cell proliferation rates in both esophagus and liver and the number of preneoplastic liver lesions from DEN/TI-treated animals at week 8. A significant lower incidence of esophageal papillomas and liver adenomas and tumor multiplicity was observed in the animals previously treated with mate at week 20. Thus, mate presented protective effects against DNA damage and esophageal and liver carcinogenesis induced by DEN. (C) 2009 Elsevier Ltd. All rights reserved.

Does mobilization for autologous stem cell transplantation damage stromal layer formation?

Autologous hematopoietic stem cell transplantation (HSCT) has proved efficient to treat hematological malignancies. However, some patients fail to mobilize HSCs. It is known that the microenvironment may undergo damage after allogeneic HSCT. However little is known about how chemotherapy and growth factors contribute to this damage. We studied the stromal layer formation(SLF) and velocity before and after HSC mobilization, through long-term bone marrow culture from 22 patients and 10 healthy donors. Patients` SLF was similar at pre- (12/22)and post-mobilization (9/20), however for controls this occurred more at pre- mobilization (9/10; p=0.03). SLF velocity was higher at pre than post-mobilization in both groups. Leukemias and multiple myeloma showed faster growth of SLF than lymphomas at post-mobilization, the latter being similar to controls. These findings could be explained by less uncommitted HSC in controls than patients at post-mobilization. Control HSCs may migrate more in response to mobilization, resulting in a reduced population by those cells.

Protective effects of Mangifera indica L extract (Vimang), and its major component mangiferin, on iron-induced oxidative damage to rat serum and liver

In vivo preventive effects of a Mangifera indica L extract (Vimang) or its major component mangiferin on iron overload injury have been studied in rats given respectively, 50, 100, 250 mg kg(-1) body weight of Vimang, or 40 mg kg(-1) body weight of mangiferin, for 7 days prior to, and for 7 days following the administration of toxic amounts of iron-dextran. Both Vimang or mangiferin treatment prevented iron overload in serum as well as liver oxidative stress, decreased serum and liver lipid peroxidation, serum GPx activity, and increased serum and liver GSH, serum SOD and the animals overall antioxidant condition. Serum iron concentration was decreased although at higher doses, Vimang tended to increase it; percent tranferrin saturation, liver weight/body mass ratios, liver iron content was decreased. Treatment increased serum iron-binding capacity and decreased serum levels of aspartate-amine transferase (ASAT) and alanine-amine transferase (ALAT), as well as the number of abnormal Kupffer cells in iron-loaded livers. It is suggested that besides acting as antioxidants, Vimang extract or its mangiferin component decrease liver iron by increasing its excretion. Complementing earlier in vitro results from our group, it appears possible to support the hypothesis that Vimang and mangiferin present therapeutically useful effects in iron overload related diseases. (C) 2007 Elsevier Ltd. All rights reserved.

A Strong Protective Action of Guttiferone-A, a Naturally Occurring Prenylated Benzophenone, Against Iron-Induced Neuronal Cell Damage

Guttiferone-A (GA) is a natural occurring polyisoprenylated benzophenone with several reported pharmacological actions. We have assessed the protective action of GA on iron-induced neuronal cell damage by employing the PC12 cell line and primary culture of rat cortical neurons (PCRCN). A strong protection by GA, assessed by the 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carbox-anilide (XTT) assay, was revealed, with IC(50) values <1 mu M. GA also inhibited Fe(3+)-ascorbate reduction, iron-induced oxidative degradation of 2-deoxiribose, and iron-induced lipid peroxidation in rat brain homogenate, as well as stimulated oxygen consumption by Fe(2+) autoxidation. Absorption spectra and cyclic voltammograms of GA Fe(2+)/Fe(3+) complexes suggest the formation of a transient charge transfer complex between Fe(2+) and GA, accelerating Fe(2+) oxidation. The more stable Fe(3+) complex with GA would be unable to participate in Fenton-Haber Weiss-type reactions and the propagation phase of lipid peroxidation. The results show a potential of GA against neuronal diseases associated with iron-induced oxidative stress.

Antinociceptive and anti-inflammatory properties of 7-hydroxycoumarin in experimental animal models: potential therapeutic for the control of inflammatory chronic pain

Objectives In the present study we investigated the anti nociceptive, anti-inflammatory and antipyretic effects of 7-hydroxycoumarin (7-HC) in animal models. Methods The effects of oral 7-HC were tested against acetic acid-induced writhing, formalin test, tail flick test, complete Freund`s adjuvant (CFA)-induced hypemociception, carrageenan-induced paw oedema, lipopolysaccharide-induced fever and the rota rod test. Key findings 7-HC (3-60 mg/kg) produced a dose-related antinociception against acetic acid-induced writhing in mice and in the formalin test. In contrast, treatment with 7-HC did not prevent thermal nociception in the tail flick test. A single treatment with 7-HC, 60 mg/kg, produced a long-lasting antinociceptive effect against CFA-induced hypernociception, a chronic inflammatory pain stimulus. Notably, at 60 mg/kg per day over 4 days the administration of 7-HC produced a continuous antinociceptive effect against CFA-induced hypernociception. 7-HC (30-120 mg/kg) produced anti-inflammatory and antipyretic effects against carrageenan-induced inflammation and lipopolysaccharide-induced fever, respectively. Moreover, 7-HC was found to be safe with respect to ulcer induction. In the rota rod test, 7-HC-treated mice did not show any motor performance alterations. Conclusions The prolonged antinociceptive and anti-inflammatory effects of 7-HC, in association with its low ulcerogenic activity, indicate that this molecule might be a good candidate for development of new drugs for the control of chronic inflammatory pain and fever.

Functional characterization of the putative Aspergillus nidulans DNA damage binding protein homologue DdbA

Nucleotide excision repair (NER) eliminates helix-distorting DNA base lesions. Seven XP-deficient genetic complementation groups (XPA to XPG) have already been identified in mammals, and their corresponding genes have been cloned. Hereditary defects in NER are associated with several diseases, including xeroderma pigmentosum (XP). UV-DDB (XPE) is formed by two associated subunits, DDB1 and DDB2. UV-DDB was identified biochemically as a protein factor that exhibits very strong and specific binding to ultraviolet (UV)-treated DNA. As a preliminary step to characterize the components of the NER in the filamentous fungus Aspergillus nidulans, here we identified a putative DDB1 homologue, DdbA. Deletion and expression analysis indicated that A. nidulans ddbA gene is involved in the DNA damage response, more specifically in the UV light response and 4-nitroquinoline oxide (4-NQO) sensitivity. Furthermore, the Delta ddbA strain cannot self-cross and expression analysis showed that ddbA can be induced by oxidative stress and is developmentally regulated in both asexual and sexual processes. The Delta ddbA mutation can genetically interact with uvsB(ATR), atmA(ATM), nkuA(KU70), H2AX-S129A (a replacement of the conserved serine in the C-terminal of H2AX with alanine), and cshB (a mutation in CSB Cockayne`s syndrome protein involved in the transcription-coupled repair subpathway of NER) mutations. Finally, to determine the DdbA cellular localization, we constructed a GFP:DdbA strain. In the presence and absence of DNA damage, DdbA was mostly detected in the nuclei, indicating that DdbA localizes to nuclei and its cellular localization is not affected by the cellular response to DNA damage induced by 4-NQO and UV light.

Low level and sub-chronic exposure to methylmercury induces hypertension in rats: nitric oxide depletion and oxidative damage as possible mechanisms

Increased risk of hypertension after methylmercury (MeHg) exposure has been suggested. However, the underlying mechanisms are not well explored. In this paper, we have analyzed whether sub-chronic exposure to MeHg increases systolic blood pressure even at very low levels. In addition, we analyzed if the methylmercury-induced hypertension is associated with a decreased plasmatic nitric oxide levels and with a dysregulation of the activities of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT), as well as the levels of MDA and glutathione. For this study, Wistar rats were treated with methylmercury chloride (100 mu g/kg per day) or vehicle. Total treatment time was 100 days. Malondialdehyde (MDA) and circulating NOx levels and superoxide dismutase (SOD) and catalase (CAT) activities were determined in plasma, whereas glutathione levels were determined in erythrocytes. Our results show that long-term treatment at a low level of MeHg affected systolic blood pressure, increasing and reducing the levels of plasmatic MDA and NOx, respectively. However, the activity of SOD did not decrease in the MeHg exposed group when compared to the control. We found a negative correlation between plasmatic nitrite/nitrate (NOx) levels and systolic blood pressure (r = -0.67; P = 0.001), and a positive correlation between MDA and systolic blood pressure (r = 0.61; P = 0.03), thus suggesting increased inhibition of NO formation with the increase of hypertension. In conclusion, long-term exposure to a low dose of MeHg increases the systolic pressure and is associated, at least in part, with increased production of ROS as judged by increased production of malondialdehyde and depressed NO availability.

Protective properties of quercetin against DNA damage and oxidative stress induced by methylmercury in rats

Aim of the study was to find out whether consumption of quercetin (QC), an abundant flavonoid in the human diet, protects against DNA damage caused by exposure to organic mercury. Therefore, rats were treated orally with methylmercury (MeHg) and the flavonoid with doses that reflect the human exposure. The animals received MeHg (30 mu g/kg/bw/day), QC (0.5-50 mg/kg/bw/day), or combinations of both over 45 days. Subsequently, the glutathione levels (GSH) and the activities of glutathione peroxidase (GPx) and catalase (CAT) were determined, and DNA damage was measured in hepatocytes and peripheral leukocytes in single cell gel electrophoresis assays. MeHg decreased the concentration of GSH and the activity of GPx by 17 and 12%, respectively and caused DNA damage to liver and blood cells, while with QC no such effects were seen. When the flavonoid was given in combination with MeHg, the intermediate and the highest concentrations (5.0 and 50.0 mg/kg/bw/day) were found to cause DNA protection; DNA migration was reduced by 54 and 65% in the hepatocytes and by 27 and 36% in the leukocytes; furthermore, the reduction in GSH and GPx levels caused by MeHg treatment was restored. In summary, our results indicate that consumption of QC-rich foods may protect Hg-exposed humans against the adverse health effects of the metal.

Evaluation of protective effects of fish oil against oxidative damage in rats exposed to methylmercury

The present study evaluates a possible protective effect of fish oil against oxidative damage promoted by methylmercury (MeHg) in sub-chronically exposed rats. Reduced glutathione peroxidase and catalase enzyme activity and reduced glutathione levels were observed in MeHg-exposed animals compared to controls. Methylmercury exposure was also associated with DNA damage. Administration of fish oil to the methylmercury-exposed animals did not ameliorate enzyme activity or glutathione levels. On the other hand, a significant DNA protective effect (about 30%) was observed with fish oil treatment. There were no differences in the total mercury concentration in rat liver, kidney, heart or brain after MeHg administration with or without fish oil co-administration. Histopathological analyses showed a significant leukocyte infiltration in rat tissues after MeHg exposure, but this effect was significantly reduced after co-administration of fish oil. Taken together, our findings demonstrate oxidative damage even after low-level MeHg exposure and the protective effect of fish oil. This protection seems not to be related to antioxidant defenses or mercury re-distribution in rat tissues. It is probably due to the anti-inflammatory effects of fish oil. (C) 2010 Elsevier Inc. All rights reserved.

Anti-snake venom properties of Schizolobium parahyba (Caesalpinoideae) aqueous leaves extract

Many medicinal plants have been recommended for the treatment of snakebites. The aqueous extracts prepared from the leaves of Schizolobium parahyba (a plant found in Mata Atlantica in Southeastern Brazil) were assayed for their ability to inhibit some enzymatic and biological activities induced by Bothropspauloensis and Crotalus durissus terrificus venoms as well as by their isolated toxins neuwiedase (metalloproteinase), BnSP-7 (basic Lys49 PLA(2)) and CB (PLA(2) from crotoxin complex). Phospholipase A(2), coagulant, fibrinogenolytic, hemorrhagic and myotoxic activities induced by R pauloensis and C. d. terrificus venoms, as well as by their isolated toxins were significantly inhibited when different amounts of S. parahyba were incubated previously with these venoms and toxins before assays. However, when S. parahyba was administered at the same route as the venoms or toxins injections, the tissue local damage, such as hemorrhage and myotoxicity was only partially inhibited. The study also evaluated the inhibitory effect of S. parahyba upon the spreading of venom proteins from the injected area into the systemic circulation. The neutralization of systemic alterations induced by i.m. injection of R pauloensis venom was evaluated by measuring platelet and plasma fibrinogen levels which were significantly maintained when S. parahyba extract inoculation occurred at the same route after R pauloensis venom injection. In conclusion, the observations confirmed that the aqueous extract of S. parahyba possesses potent snake venom neutralizing properties. It may be used as an alternative treatment to serum therapy and as a rich source of potential inhibitors of toxins involved in several physiopathological human and animal diseases. Copyright (c) 2008 John Wiley & Sons, Ltd.

Evaluation of the genotoxicity of Crotalus durissus terrificus snake venom and its isolated toxins on human lymphocytes

In the present study, experiments were carried out to evaluate the mutagenic potential and genotoxic effects of Crotalus durissus terrificus snake venom and its isolated toxins on human lymphocytes, using the micronucleus and comet assays. Significant damage to DNA was observed for crotoxin and crotapotin (CA). Basic phospholipase A(2) (CB) and crotamine did not present any mutagenic potential when evaluated by the micronucleus test. C. d. terrificus crude venom was able to induce the formation of micronuclei, similarly to the mutagenic drug used as a positive control. In the comet assay, all the toxins tested (crotamine, crotoxin, CB and CA) and C. d. terrificus venom presented genotoxic activity. Studies on the cytogenetic toxicology of animal venoms and their isolated proteins are still very scarce in the literature, which emphasizes the importance of the present work for the identification and characterization of potential therapeutic agents, as well as for the better understanding of the mechanisms of action of toxins on the human body. (C) 2011 Elsevier B.V. All rights reserved.

Lutein improves antioxidant defense in vivo and protects against DNA damage and chromosome instability induced by cisplatin

Lutein (LT) is the second most prevalent carotenoid in human serum, and it is abundantly present in dark, leafy green vegetables. The objectives of this study were to evaluate the genotoxicity and mutagenicity of LT, and its protective effects in vivo against DNA damage and chromosome instability induced by cisplatin (cDDP). For this purpose, we used the comet assay and micronucleus (MN) test, and we evaluated the antioxidant effects of LT by determination of enzymatic (catalase-CAT) and non-enzymatic (reduced glutathione-GSH) activity. Mice were divided into six groups: cDDP, mineral oil (OM), LT groups and LT + cDDP groups. To perform the MN test on peripheral blood (PB) cells, blood samples were collected before the first treatment (T0), and 36 h (T1) and 14 days (T2) after the first treatment. To perform the comet assay, blood samples were collected 4 h after the first and the last treatment. Oxidative capacity was analyzed in total blood that was collected 24 h after the last treatment, when bone marrow (BM) sample was also collected for the MN test. No genotoxic or mutagenic effects of LT were observed for the doses evaluated. We did find that this carotenoid was able to reduce the formation of crosslinks and chromosome instability induced by cDDP. No differences were observed in CAT levels, and LT treatment increased GSH levels compared with a negative control group, reinforcing the role of this carotenoid as an antioxidant.

Evaluation of Environmental Mycobacteria Contamination in a Specific Pathogen Free Animal Facility from a Tropical Country

P>With the evidence showing the protection variability of bacille Calmette-Guerin, new potential vaccines for tuberculosis have been tested around the world. One of the general concerns in tuberculosis vaccine development is the possibility of priming the host immune system with prior exposure to environmental mycobacteria antigens, which can change the efficacy of subsequent vaccination. As there is a great homology between the species from Mycobacterium genera, the previous contact of experimental animals with environmental mycobacteria could sensitize the mice and, in this way, could influence subsequent vaccine research. The aim of our study was to investigate critical points in an animal facility to search for environmental mycobacteria that eventually could be in direct or indirect contact with the experimental animals. Samples were collected from surfaces of walls, floor, animal cages and shelves and analysed using the Ogawa-Kudoh decontamination method. Samples of drinking water, food and sawdust were collected for analysis by the NALC/NaOH decontamination method. Also, the samples were cultivated directly in broth medium, without any method for decontamination. After decontamination methods, we observed bacterial colony growth in 4.31% of the total of samples analysed. These samples were stained with Ziehl-Neelsen and we did not detect any acid-fast bacilli, suggesting that the animal facility analysed is free from contamination by environmental mycobacteria and is not a source of mycobacterial antigens. Furthermore, our study showed a new paradigm in tuberculosis vaccine development: concern about the animal facility environment in terms of immune system priming of experimental animals by nascent bacterial contaminants.