Estudo do efeito dos metabólitos do benzeno e tolueno sobre as mitocôndris cerebrais e hepáticas de ratos

Aim: The aim of this work was to investigate the hypothesis that catechol and 3MC inhibit FADH2-linked basal respiration in mitochondria isolated from rat liver and brain homogenates. Moreover, catechol ability to induce DNA damage in rat brain cells through the comet assay (alkaline single-cell gel electrophoresis assay) was also observed. Methods: Two different catechols were evaluated: pirocatechol (derived from benzene) and 3-methylcatechol (derived from toluene); rat liver and brain homogenates were incubated with 1mM catechol at pH 7.4 for up to 30 minutes. After that, mitochondrial fractions were isolated by differential centrifugation. Basal oxygen uptake was measured using a Clark-type electrode after the addition of 10 mM sodium succinate for a period of 12 minutes. In additional experiments, rat brain cells were treated with 1, 5 and 10mM pirocatechol for up to 20 minutes at 37º C, and submitted to electrophoresis. Results: Catechols (pirocatechol and 3methylcatechol) induced a time-dependent partial inhibition of FADH2-linked basal mitochondrial respiration. Indeed, pirocatechol was able to produce a dosedependent DNA oxidative damage in rat brain cells by 2 and 4 injury levels. These results suggest that reactive oxygen species generated by the oxidation of catechols, induced an impairment on mitochondrial respiration and a DNA damage, which might be related to their citotoxicity. Conclusion: Catechols produced an inhibition of basal respiration associated to FADH2 in isolated liver and brain mitochondria; 3-methylcatechol, at the same concentration, produced similar toxicity in the mitochondrial model. Indeed, pirocatechol induced a DNA damage in rat brain cells, mainly observed in comets formation and consequent DNA degradation

Análise toxicológica in vitro e in vivo de uma fucana antitrombótica da alga marrom Spatoglossum schdöederi

Fucan is a term used to denominate a family of sulfated polysaccharides rich in L-fucose. They are extracted mainly from the extracellular matrix of brown algae and echinoderms. The brown alga Spatoglossum schröederi (Dictyotaceae) has three heterofucans named A, B and C. Our research group have been extracted non anticoagulant heterofucan from S. schröederi which possess antithrombotic activity in vivo. However, their toxicity in vitro and in vivo has not yet been determined. For the results in toxicity in vitro, we observed that the fucan A at 20, 500 and 1000 μg/plate showed no mutagenic activity in Kado test (Microsuspension), when the bacterial strains TA97a, TA98, TA100 and TA102, with and without S9 were used. The comet assay showed that fucan A (from 20 to 1000 μg/mL) did not cause any genotoxic effect on CHO cells. There was no damage to the DNA of these cells, as evidenced by the tail length and tail moment, which were similar to that found for the negative control. The fucan A from S. schröederi was administered at 20 μg/g of rat (dose which it showed high antithrombotic activity) during two months. After that, the animals were killed and examined. The data showed that fucan A did not cause any change in biochemistry and hematological parameters, as well as, in the morphology and size of the rat s organs analyzed. In conclusion, this study indicates that fucan is a compound with potential pharmacological that has no toxicity

Análise da presença de agentes mutagênicos nas águas do Rio Pitimbú/RN

The Pitimbu River is located at the oriental portion of the State of Rio Grande do Norte, including three importants cities named Macaíba, Parnamirim e Natal. Although its high importance as a water source, which supplys great part of the South Zone of the Natal city, this river receives a large quantity of domestic and industrial waste water without treatment. The Pitimbu River headhas its river-head located in the city of Macaiba, goes through Parnamirim, then it flowing into at the Jiqui Lake in Natal. The aim of this study was to evaluate, qualitatively and quantitatively, the environmental quality of the Pitimbu River by genotoxicity bio-assays, which are important tools for genetics toxicological evaluation. In this work, five samples sites, distributed along the river, were used to collect water samples. Another point site, located near Jiqui lake, was used to collect drinkable water, which was treated by CAERN, the water treatment entreprise of Rio Grande do Norte. The following assays where used to evaluate the quality of these samples: Allium cepa assay; Comet assay; Micronuclei (MN) assay; and Ames test. For the Allium cepa assay, sixteen specimes where used for each water sample from the sample sites. In this assay both microscopic, like cytogenetic damage, and macroscopic aspects, as morphological variation were evaluated. Red blood cells from periferical blood of the Crenicichla menezesi native specie were used not only for the MN assay, but also for the Comet assay. These fishes were collected at different points on the Pitimbu River and the negative control was developed using fishes of the same species that were bring to the laboratory and maintained for 100 days in the optimal experimental conditions. For the Ames test, TA100, YG1042, TA98 and YG1041 strains were used in the directed method without metabolic activation. The results found by the Allium cepa assay showed that two water sample sites induced increase of mitotic index (IM). Additionally, compared to the control, all the water samples increased the chromossomal aberrations frequency and/or micronucleus. Among the sample sites, two also showed an abnormal growth rate in its root and two samples induced morphological alteration. With the MN test in red blood cells, a high frequence of MN was observed in tree sample. By comparing all the results obtained on the water sample points and with the negative control, a significant variation on the MN frequency was observed. Positive results were also observed for the same sample to water test by the Comet assay. These results allow concluding that the proposed specie Crenicichla menezesi has a good profile as a bio-indicator for the evaluation of environmental water quality and the MN and comet test can be usuful for in situ evaluation. By the Ames test, it was possible to detect the mutagenic activity on the waters from the Pitimbu River in different levels of mutagenicity. This result suggests that this river has several substances that induced changes directly to the DNA. The mechanisms involved to this phenomenon could be by both processes, by changing of the reading frame and by nucleotide substitution. These data set indicate the presence of mutagenic agents, which can represent in risk to biot and human beens

Análise da genotoxicidade das águas da Lagoa da Extremoz - RN

The contamination of the waters resources for wastewater from industrial, agricultural, and domestic sources is a serious environment problem, compromising its use for human consumption and agriculture. The Extremoz-RN Lake is an important freshwater source for the supply of the city of Natal, supplying a population of approximately 160,000 habitants. This aquatic body is located near an industrial pole which can be a serious risk factor for quality of its waters. The objectives of this study were examined the genotoxicity of Extremoz Lake between September of 2006 and January of 2008, by a combination of the Allium micronucleus test, piscine micronucleus test and the comet assay in erythrocytes from peripheral blood of Oreochromis niloticus. Additionally, the level of eight different heavy metals was quantified through spectrometry of atomic absorption of flame. The Allium test did not detect increase in the frequencies of micronucleus in none of the analyzed periods, however a strong cytotoxic activity was demonstrated for decrease in mitotic index in the analyses carried in April and July of 2007. Negative results had been detected in the frequencies of micronucleus in O. niloticus. A statistic significant increase was observed in the levels of DNA damage in comet assay carried in July of 2007. The results of the chemical analysis had detected increase in the levels of cadmium, chromium, copper, nickel, lead and zinc in different periods. These results demonstrated an alteration of the water s quality of the Extremoz Lake caused for the contamination for heavy metals and increase of DNA strand breaks. The use of biomonitoring program of the heavy metal and other pollutants with genotoxic potential combinated with genotoxicity assays is recommends.

Avaliação da genotoxicidade das águas sueprficiais da Barragem Engenheiro Armando Ribeiro Gonçalves, Assu/RN

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Avaliação da genotoxicidade em mulheres com síndrome dos ovários policísticos: impacto da dieta

Introduction: Polycystic Ovary Syndrome (PCOS), present in 6-12% of women of reproductive age, the criterion of Rotterdam, is characterized by hyperandrogenism, insulin resistance (IR) and its inflammatory state, exacerbated by obesity and factors associated with the increase in damage DNA. Weight loss, combined with healthy eating, acts restoring the reproductive and metabolic functions in the SOP, though its influence in reducing DNA damage in PCOS are unknown. Aim: To investigate whether there are differences between DNA damage markers and factors of cardiometabolic risk in women with PCOS and control, and evaluate the effectiveness of nutritional intervention in DNA damage markers and cardiometabolic risk markers in overweight and obese women with PCOS. Methods: the study was conducted in two studies and the participants were aged between 18 and 35 years. In the first study, a prospective case-control, were included 27 women diagnosed with PCOS and 20 controls. In the second study, clinical trial of nutritional intervention with 12-week calorie-restricted diet 500Kcal / day. The genotoxicity, DNA damage (intensity tail, tail moment and tail length) was evaluated by the comet assay. Anthropometric data, dietary intake, hormonal, biochemical and inflammatory were evaluated in different studies. Results: there was no significant difference between the DNA damage marker tail intensity (p = 0.18), tail moment (p = 0.76) and tail length (p = 0.109) in PCOS when compared to the control group. Data after nutritional intervention in PCOS women with overweight and obesity showed a decrease in DNA damage markers: tail intensity (24.35 ± 5.86 - pre-diet vs. 17.15 ± 5.04 -Post-diet) and tail moment (20.47 ± 7.85 - pre-diet vs. 14.13 ± 6.29 -post-diet) (p <0.001). Reduction of weight (3.5%) and decreased cardiometabolic markers IR and hyperandrogenism. Conclusion: women with PCOS have a worse cardiometabolic risk profile compared to control however similar genotoxicity identified by DNA damage. Nutritional intervention reduced the genotoxicity of overweight and obese women with PCOS, and reduce the factors of cardiometabolic risk.

Análise toxicológica in vitro e in vivo de uma fucana antitrombótica da alga marrom Spatoglossum schdöederi

Fucan is a term used to denominate a family of sulfated polysaccharides rich in L-fucose. They are extracted mainly from the extracellular matrix of brown algae and echinoderms. The brown alga Spatoglossum schröederi (Dictyotaceae) has three heterofucans named A, B and C. Our research group have been extracted non anticoagulant heterofucan from S. schröederi which possess antithrombotic activity in vivo. However, their toxicity in vitro and in vivo has not yet been determined. For the results in toxicity in vitro, we observed that the fucan A at 20, 500 and 1000 μg/plate showed no mutagenic activity in Kado test (Microsuspension), when the bacterial strains TA97a, TA98, TA100 and TA102, with and without S9 were used. The comet assay showed that fucan A (from 20 to 1000 μg/mL) did not cause any genotoxic effect on CHO cells. There was no damage to the DNA of these cells, as evidenced by the tail length and tail moment, which were similar to that found for the negative control. The fucan A from S. schröederi was administered at 20 μg/g of rat (dose which it showed high antithrombotic activity) during two months. After that, the animals were killed and examined. The data showed that fucan A did not cause any change in biochemistry and hematological parameters, as well as, in the morphology and size of the rat s organs analyzed. In conclusion, this study indicates that fucan is a compound with potential pharmacological that has no toxicity