A suplementação de ácidos graxos ômega 3 e triglicérides de cadeia média não alteram os indicadores metabólicos em um teste de exaustão

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effects of fasting and intermittent fasting on rat hepatocarcinogenesis induced by diethylnitrosamine

The influences of fasting on DEN-initiation and of intermittent fasting (IF) on the rat liver chemical carcinogenesis process were evaluated in a 52-week long assay. Three groups of adult male Wistar rats were used: Groups I to 3 were treated with a single i.p. injection of 200 mg/kg of diethylnitrosamine (DEN). Group 2 was submitted to 48 h fasting prior to DEN treatment. After the 4th week, Group 3 was submitted to IF, established as 48 h weekly fasting during 48 weeks, while Groups I and 2 were fed ad libitum until the 52nd week. All animals were submitted to 70% partial hepatectomy and sacrificed at the 3rd and 52nd weeks, respectively. Fasting prior to DEN-initiation did not influence the development of altered foci of hepatocytes (AFHs) and of hepatic nodules (Group 2 vs. Group G1). IF inhibited the development of preneoplastic lesions, since this dietary regimen decreased the number and the size of glutathione S-transferase (GST-P) positive foci and the number and size of liver nodules (Group G3 vs. Group G1), the inhibitory effect of IF was also reflected in the development of clear and basophilic cell foci. These results indicate that long-term IF regimen exerts an anti-promoting effect on rat hepatocarcinogenesis induced by DEN. (C) 2002 Wiley-Liss, Inc.

Protective action of propolis on the rat colon carcinogenesis

Propolis is a honeybee product with several biological and therapeutical properties. Its effect on the process of colon carcinogenesis and DNA damage were evaluated in the male Wistar rats using the aberrant crypt foci (ACF) assay and the comet assay, respectively. For both tests, animals were treated with the colon carcinogen 1,2 dimethylhydrazine (DMH, 40 mg/kg, s.c.) for 2 weeks (two injections/week) in order to induce both DNA damage and ACF. The animals were divided into groups that received propolis (ethanolic extract) at three different doses (10, 30, and 90 mg/kg b.w., by gavage), either simultaneously or after DMH treatment. For the comet assay, peripheral blood samples were collected 4 h after the last DMH treatment. All animals were sacrificed at the 5th week for evaluation of ACF. The results show that only the intermediate dose (30 mg/kg) of propolis, administered after DMH initiation, is significantly associated to a smaller number of aberrant crypts in the distal colon. No effect on DNA damage in peripheral blood cells, however, was verified by the comet assay. These data suggest that propolis has a protective influence on the process of colon carcinogenesis, suppressing the development of preneoplastic lesions, and probably exerts no protection against the initiation of carcinogenesis.

Ovarian morphometric characterization and in vitro maturation of oocytes obtained from buffalo (Bubalus bubalis) ovaries - partial results

Buffalo ovaries were collected from a slaughterhouse (Frigol, Brazil) and transported to the laboratory in saline solution at 36 degrees C. The ovaries were dissected to realize the evaluations (weight, length, width and height of the ovary; corpus luteum and dominant follicle diameters). The Cumulus-oocyte complexes (COCs) were recovered by aspiration of 2-8 mm follicles. Selected COCs were matured in TCM 199 supplemented with 10% fetal bovine serum, sodium pyruvate, LH, FSH, estradiol and gentamicin. In vitro maturation was carried out at 38.5 degrees C for 22-24 h and 34-36 h. For the evaluation of the nuclear maturation the oocytes were placed in TCM 199 medium added with type v hialuronidase where the granulosa cells were extracted. The denuded oocytes were transferred to 10 mu l of Hoescht 33342 and the chromosomic configuration was evaluated. The oocytes were classified according to meiosis stage in: Germinal Vesicle, Germinal Vesicle Breakdown, Metaphase I, Metaphase II and Degenerated. The means of weight, length, width and height of the ovary were 3.83 g, 2.27 cm, 1.08 cm and 1.56 cm, respectively. The means of corpus luteum and dominant follicle diameters were 1.40 cm and 7.77 mm. The proportion of oocytes that reached metaphase II stage was: 36.68%.

The use of transmission electron microscopy and oocyte transfer to evaluate in vitro maturation of equine oocytes in different culture conditions

The current study evaluates the ability of equine oocytes matured in different conditions to undergo nuclear and cytoplasmic maturation.. After oocyte transfer, embryonic development was diagnosed at 1.5 and 90 days of gestation. For each group, immature oocytes obtained from slaughterhouse ovaries were matured in vitro (5 replicates). In experiment I, three different media were tested. HTF:BME, SOFaa, and TCM 199. In experiment 11, the HTF:BME was chosen as maturation medium containing pFSH, eFSH, or eFSH + eGH. Nuclear maturation was estimated after stripping the oocytes and staining with Hoechst 33342. The evaluation of cytoplasmic maturation was performed by transmission electron microscopy. For oocyte transfer, six non-cycling recipient mares were used, and 8 to 15 oocytes were transferred in each mare. In experiment I, the results showed no differences (P > .05) in nuclear maturation (MII) among experimental groups. The percentage of MII was 29.3 ( +/- 9.6), 23.4 ( +/- 8.4), and 13.5 ( +/- 12.4) for HTF:BME, SOF, and TCM, respectively. In experiment II, all media tested were efficient in inducing metaphase II. Also, no statistical differences (P > .05) were observed in percentages of nuclear maturation rates when porcine (37.1 +/- 22.4) or equine (25.8 +/- 8.2) FSH were used, or when eFSH + eGH was added to HTF:BME (29.4 +/- 12.3). The analysis of cytoplasmic morphology of oocytes cultured in TCM 199 and SOFaa showed signs of incomplete cytoplasmic maturation and premature cortical reaction. Meanwhile, oocytes cultured in HTF:BME medium presented cytoplasmic characteristics similar to those described by others for in vivo-matured oocytes. The addition of eFSH to the HTF:BME medium resulted in an improvement of cytoplasmic morphology. After oocyte transfer, two mares became pregnant, one from pFSH group and one from eFSH+eGH group. These results indicate that although in vitro matured equine oocytes are capable of fertilization and embryonic development, the percentage of competent oocytes is still low.

Fetotoxicity caused by the interaction between zinc and arsenic in mice

Arsenic is an environmental pollutant that induces congenital malformations in experimental models and can contribute to human birth defects. The environmental exposure to arsenic is relatively small when compared with the doses required to cause teratogenicity in mice and other laboratory animals. In order to study the action of zinc in the arsenic-induced teratogenicity, in the present work mice were either pretreated with zinc and later with arsenic or were treated simultaneously with zinc and arsenic in vivo and in vitro. Following administration of arsenate on gestation day 8, pregnant females were killed on the 17th day of gestation; maternal and fetal data were collected by laparotomy and used to calculate reproductive parameters. Fetuses were analyzed for the presence of external malformation and, after the appropriate processing, visceral and skeletal analyses were accomplished. Conceptuses were exposed in whole embryo culture to arsenicals on gestation day 8 (3-6 somite stage). After a 26 h culture period, morphological development was assessed. Neither pretreatment with zinc nor simultaneous administration of zinc prevented arsenic teratogenicity in these experimental models. (C) 2002 Wiley-Liss, Inc.

Characterization of small-scale fisheries in the Camamu-Almada basin, southeast state of Bahia, Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Melatonin in maturation media fails to improve oocyte maturation, embryo development rates and DNA damage of bovine embryos

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

Absence of promoting potential of bracken fern (Pteridium aquilinum) in rat urinary bladder carcinogenesis induced by N-butyl-N-(4-hydroxybutyl)-nitrosamine and uracil

Conventional studies on bracken fern (Pteridium aquilinum; PA) carcinogenicity have used high dietary concentrations (around 30%) and long-term exposure (up to 52-70 weeks) without consideration of the multistep character of the chemical carcinogenesis process. The present study evaluated specifically the promoting potential of 3-5% dietary crude PA in the rat urinary bladder mucosa in a 32-week-long initiation-promotion assay for chemical carcinogenesis. Initiation of urothelial carcinogenesis was accomplished with N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN). Uracil (U) was provided through the diet in order to expand the population of initiated cells. Seven groups (C) of male Wistar rats were submitted to the following treatments: G1 = BBN (n = 8); G2 = U (n = 10); G3 = BBN-U (n = 9); G4 = BBN-PA-U-PA (n = 16); G5 = PA (n = 8); G6 = BBN-PA (n = 10); G7 = PA-U-PA (n = 12). At the end of the experiment rats presenting epithelial papillary or nodular hyperplasia (PNH), papillomas (PAP), or simultaneous PNH plus PAP numbered, respectively G1: 2-0-1; G2: 0-0-0; G3: 3-0-2; G4: 4-3-2; G5: 1-0-1; G6: 8-0-0; and G7: 0-0-0, with no significant differences in the incidence of lesions among the groups. More frequent and more severe lesions occurred in BBN-initiated animals, predominantly in those also exposed to uracil (G3 and G4). Low-dose crude bracken fern in the diet does not promote rat urinary bladder carcinogenesis after a 32-week period of exposure, even when the initiated urothelial cell population has been expanded through a mechanical stimulus. (C) 1995 Wiley-Liss, Inc.

Role of roscovitine and IBMX on kinetics of nuclear and cytoplasmic maturation of bovine oocytes in vitro

The 3-isobutyl-1-methylxanthine (IBMX) is able to prevent resumption of meiosis by maintaining elevated cyclic AMP (cAMP) concentrations in the oocyte, and roscovitine, a purine known to specifically inhibit MPF kinase activity, maintains bovine oocytes at the germinal vesicle (GV) stage. The present study was conducted to analyze whether cytoplasmic maturation (examined by the pattern of cortical granule (CG) distribution) of bovine oocytes is improved during meiotic arrest with IBMX and roscovitine. Oocytes were matured in vitro in a 10% Knockout(SR) supplemented TCM-199 medium (Control) with either 0.5 mM IBMX or 25 mu M roscovitine (ROSC). Oocytes were stained with fluorescein isothiocyanate conjugated Lens culinaris agglutinin (FITC-LCA) for CG evaluation and with Hoechst 33342 for nuclear stage assessment. At 16 h of culture, the percentage of oocytes remaining in the GV stage was higher (P < 0.05) in the ROSC group (32.41%) compared with the Control and IBMX groups (8.61% and 9.73%, respectively). At 24h of culture, progression of meiosis to M II stage was retarded (P < 0.05) in the ROSC group (24.05%) compared to the Control (60.20%), whereas the IBMX group (33.88%) showed no significant difference to the other two groups. At 16h of maturation, the proportion of oocytes with CG in clusters (immature cytoplasm) was similar between the groups, as was the percentage of peripheral CG (mature) at 24h of maturation. The results of the present study demonstrated that the meiotic inhibitors IBMX and roscovitine delay the progression of nuclear maturation without affecting cytoplasmic maturation, assessed by the analysis of CG repositioning. (c) 2006 Elsevier B.V. All rights reserved.

Mushroom-derived preparations in the prevention of H2O2-induced oxidative damage to cellular DNA

Aqueous extracts of the sporophores of eight mushroom species were assessed for their ability to prevent H2O2-induced oxidative damage to cellular DNA using the single-cell gel electrophoresis (Comet) assay. The highest genoprotective effects were obtained with cold (20°C) and hot (100°C) water extracts of Agaricus bisporus and Ganoderma lucidum fruit bodies, respectively. No protective effects were observed with Mushroom Derived Preparations (MDPs) from Flammulina velutipes, Auricularia auricula, Hypsizygus marmoreus, Lentinula edodes, Pleurotus sajor-caju, and Volvariella volvacea. These findings indicate that some edible mushrooms represent a valuable source of biologically active compounds with potential for protecting cellular DNA from oxidative damage. © 2002 Wiley-Liss, Inc.

Efeito do FGF10 na maturação oocitária e produção de embriões bovinos in vitro

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Maturação in vitro de oócitos ovinos com o uso da roscovitina e ciclohexemida

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

Vitrificação de embriões bovinos produzidos in vivo e in vitro após lipólise química

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

Viabilidade da produção in vitro de embriões ovinos em meio de maturação suplementado com soro fetal bovino (SFB) ou albumina sérica bovina (BSA) acrescido ou não de cisteamina

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)