O Orlistat é um membro de uma classe de drogas usadas como tratamento para obesidade. No entanto, a segurança de seu uso em longo prazo ainda não é conhecida. O Orlistat exerce sua atividade no lúmen do trato gastrintestinal inibindo a enzima lipase pancreática, responsável pela hidrólise dos triacilglicerídeos normalmente ingeridos com a dieta. Esse medicamento, quimicamente sintetizado, é um derivado da lipstatina, inibidora natural da lipase produzida pelo Streptomyces toxytricini. Assim, a excreção de gordura fecal fica significativamente aumentada com o uso do Orlistat. Estudos epidemiológicos e em modelos experimentais, sugerem que o aumento das dietas hipergordurosas tem efeito promotor para o câncer colorretal. Tal efeito deve ser relacionado, pelo menos parcialmente, às mudanças intra-colônicas causadas pela ação direta da gordura nas células da mucosa do cólon, os colonócitos. O estudo atual tem como objetivo verificar os efeitos do Orlistat na formação colônica de focos de criptas aberrantes (FCA) e na proliferação celular epitelial da mucosa gastrintestinal. Ratos Wistar machos receberam dieta padrão ou dieta com aumento de gordura, suplementada ou não com Orlistat (200 mg/kg), e duas doses semanais do carcinógeno químico Dimetilhidrazina (DMH) (25 mg/kg). Após 30 dias, nos animais tratados com DMH, o Orlistat foi associado a um aumento significativo no número de FCAs colônicos e na proliferação celular epitelial da mucosa do cólon, independentemente da dieta. Os achados obtidos neste trabalho permitem concluir que o aumento do teor de gordura na luz do cólon distal, em decorrência da ação do Orlistat, pode potencializar a ação da DMH na formação de FCAs e no aumento da proliferação celular epitelial da mucosa colônica. / Orlistat is a member of a drug class used as obesity treatment. However, the security of its use in a long period of time is not known yet. Orlistat has its activity in the lumen of the gastrointestinal tract inhibiting the pancreatic lipase enzyme responsible for the hydrolyze of the triglycerides that usually are swallowed with the diet. This drug chemically synthesized, is a derived from lipstatina, that inhibit naturally the lipase produced by Streptomyces Toxytricini. So, the excretion of fat excrement stays significantly increased with the use of Orlistat. Epidemiologic studies and in experimental pattern, suggest that the increase of the high-fat diets facilitate the appearance of the colorectal cancer. Such effect must be related, at least partially to the changes intracolonic caused by the direct action of the fat in the cells of the colon mucous, the colonocytes. The current study has as objective to check the effects of the Orlistat on the formation of rat colonic aberrant crypt foci (ACF) and in the epithelial cell proliferation of the gastrointestinal mucous. Male Wistar rats received either a standard diet or a high fat diet (HFD), supplemented or not with Orlistat (200 mg/kg chow) and two doses of the carcinogen dimethyl-hydrazine (25 mg/Kg). After 30 days, Orlistat was associated to a significant increase in the number of colonic ACFs and cell proliferation in DMH-treated animals, independently of the HFD. The find got in this study permit to conclude that the increase in the level of adiposity inside the distal colon, due to Orlistat action, can potencializar the DMH action in the formation of ACFs and in the increase of epithelial cell proliferation of the colônica mucous.

O Orlistat é um membro de uma classe de drogas usadas como tratamento para obesidade. No entanto, a segurança de seu uso em longo prazo ainda não é conhecida. O Orlistat exerce sua atividade no lúmen do trato gastrintestinal inibindo a enzima lipase pancreática, responsável pela hidrólise dos triacilglicerídeos normalmente ingeridos com a dieta. Esse medicamento, quimicamente sintetizado, é um derivado da lipstatina, inibidora natural da lipase produzida pelo Streptomyces toxytricini. Assim, a excreção de gordura fecal fica significativamente aumentada com o uso do Orlistat. Estudos epidemiológicos e em modelos experimentais, sugerem que o aumento das dietas hipergordurosas tem efeito promotor para o câncer colorretal. Tal efeito deve ser relacionado, pelo menos parcialmente, às mudanças intra-colônicas causadas pela ação direta da gordura nas células da mucosa do cólon, os colonócitos. O estudo atual tem como objetivo verificar os efeitos do Orlistat na formação colônica de focos de criptas aberrantes (FCA) e na proliferação celular epitelial da mucosa gastrintestinal. Ratos Wistar machos receberam dieta padrão ou dieta com aumento de gordura, suplementada ou não com Orlistat (200 mg/kg), e duas doses semanais do carcinógeno químico Dimetilhidrazina (DMH) (25 mg/kg). Após 30 dias, nos animais tratados com DMH, o Orlistat foi associado a um aumento significativo no número de FCAs colônicos e na proliferação celular epitelial da mucosa do cólon, independentemente da dieta. Os achados obtidos neste trabalho permitem concluir que o aumento do teor de gordura na luz do cólon distal, em decorrência da ação do Orlistat, pode potencializar a ação da DMH na formação de FCAs e no aumento da proliferação celular epitelial da mucosa colônica. / Orlistat is a member of a drug class used as obesity treatment. However, the security of its use in a long period of time is not known yet. Orlistat has its activity in the lumen of the gastrointestinal tract inhibiting the pancreatic lipase enzyme responsible for the hydrolyze of the triglycerides that usually are swallowed with the diet. This drug chemically synthesized, is a derived from lipstatina, that inhibit naturally the lipase produced by Streptomyces Toxytricini. So, the excretion of fat excrement stays significantly increased with the use of Orlistat. Epidemiologic studies and in experimental pattern, suggest that the increase of the high-fat diets facilitate the appearance of the colorectal cancer. Such effect must be related, at least partially to the changes intracolonic caused by the direct action of the fat in the cells of the colon mucous, the colonocytes. The current study has as objective to check the effects of the Orlistat on the formation of rat colonic aberrant crypt foci (ACF) and in the epithelial cell proliferation of the gastrointestinal mucous. Male Wistar rats received either a standard diet or a high fat diet (HFD), supplemented or not with Orlistat (200 mg/kg chow) and two doses of the carcinogen dimethyl-hydrazine (25 mg/Kg). After 30 days, Orlistat was associated to a significant increase in the number of colonic ACFs and cell proliferation in DMH-treated animals, independently of the HFD. The find got in this study permit to conclude that the increase in the level of adiposity inside the distal colon, due to Orlistat action, can potencializar the DMH action in the formation of ACFs and in the increase of epithelial cell proliferation of the colônica mucous.

Hormone replacement therapy and estrogen replacement therapy have shown the ability to reduce risk of colon cancer development in clinical and animal studies, but in vitro research has been unable to reproduce an estradiol (E2) induced response in colon cancer cell lines. We demonstrated that young adult mouse colonocytes (YAMC, non-malignant colonocytes) exhibit an anti-proliferative response to E2 treatment. These cells demonstrate reduced cell culture growth and increased apoptosis in response to E2. YAMC cells containing an activated Ras mutation are considered to be malignantly transformed, and lose the ability to respond to E2 treatment. Fulvestrant (ICI) was used as an estrogen receptor antagonist to determine that these results were estrogen receptor mediated. Furthermore, this effect was demonstrated to require the presence of ER? through the use of a transgenic ERbeta knockout mouse. In these mice, the presence of E2 significantly reduced the formation of azoxymethane induced premalignant lesions. Since YAMC cells exhibit an anti-proliferative response to E2 treatment, we utilized isogenic YAMC cell lines with and without a dominant negative p53 mutation to demonstrate that this E2 induced action involves p53 activity. E2 treatment results in increased p53 transcriptional activity and a pro-apoptotic change in expression of p53 downstream targets. Presence of the dominant negative p53 mutant nullifies these effects of E2 treatment. The involvement of p53 in the previously described protection against AOM induced premalignant lesions, was investigated using wild type and heterozygous p53 knockout (Het p53KO) mice. The reduction in p53 protein corresponded to reduced effectiveness of E2 treatment on the prevention of premalignant lesion formation in Het p53KO mice. In summary, our data indicate that E2 treatment induces anti-proliferative responses in non-malignant colonocytes and protects against the formation of carcinogen-induced premalignant lesions. These effects require the presence of functional ER? and p53. Further studies are required to more thoroughly elucidate the specific interactions and downstream effects of ER? and p53 in response to E2 stimulation.

Milk fat globule membrane surrounds the fat droplets of milk. It is a biopolymer containing primarily membrane glycoproteins and polar lipids which contribute to its properties as a possible neutraceutical. The aims of the studies were to determine if dietary milk fat globule membrane: (1) confers protection against colon carcinogenesis; and (2) promotes gut mucosal integrity while decreasing inflammation compared to diets containing corn oil or anhydrous milk fat. Aim 1. Three dietary treatments differing only in the fat source were formulated: (1) AIN-76A, corn oil; (2) AIN-76A, anhydrous milk fat; and (3) AIN-76A, 50% milk fat globule membrane, 50% anhydrous milk fat. Each diet was formulated to contain 50 g/kg diet of fat and to be identical in macro and micro nutrient content. To assess protection against colon carcinogenesis, male, weanling Fischer-344 rats were randomly assigned to one of the three dietary treatments. Animals were injected with 1,2-dimethylhydrazine once per week at weeks 3 and 4. After 13 weeks animals were sacrificed, colons were removed, and aberrant crypt foci were counted by microscopy. Rats fed the milk fat globule membrane diet (n = 16) had significantly fewer aberrant crypt foci (20.9 ± 5.7) compared to rats fed corn oil (n = 17) or anhydrous milk fat (n = 16) diets (31.3 ± 9.5 and 29.8 ± 11.4 respectively; P < 0.05). Aim 2. Male BALB/c mice were randomly assigned to one of two diets: AIN- 76A, corn oil or AIN-76A, 50% milk fat globule membrane, 50% anhydrous milk fat. After 5 weeks mice were injected with saline vehicle control or lipopolysaccharide and gavaged with dextran-FITC. To assess gut mucosal integrity and inflammation, serum samples were assayed for dextran-FITC 24 and 48 hours after gavage, and a panel of 16 cytokine concentrations was analyzed. Serum concentrations of IL-6, IL-10, IL-17, MCP-1, IFNγ, and TNFα decreased and gut permeability decreased 45% in lipopolysaccharide challenged mice fed milk fat globule membrane diet compared to control diet at 24 hours (P < 0.05). Overall, the results of these aims suggest that diets containing milk fat globule membrane are protective against colon carcinogenesis, inhibit the inflammatory response, and protect against gastrointestinal stress.

Submitted by Michele Mologni (mologni@unoeste.br) on 2019-01-29T18:40:59Z No. of bitstreams: 1 Sandra Cristina Genaro.pdf: 1632390 bytes, checksum: 89f6ec224705d20a5ce967976b70a4c3 (MD5) / Made available in DSpace on 2019-01-29T18:40:59Z (GMT). No. of bitstreams: 1 Sandra Cristina Genaro.pdf: 1632390 bytes, checksum: 89f6ec224705d20a5ce967976b70a4c3 (MD5) Previous issue date: 2018-11-22 / Among the existing types, colorectal cancer (CRC) affects approximately one million people per year, considered the second most common cause of death among women and the third most prevalent in men. Risk factors are genetic syndromes; inflammatory bowel diseases; family history; sedentary lifestyle; obesity, low fiber, high saturated fats, smoked foods or built-in food, excess red meat (> 300g/week), preparation mode in high temperatures and on the ember; medications; smoking, and excessive alcohol. These factors alter the intestinal microbiome which is colonized by pathogenic bacteria capable of provoking a local inflammatory response that, in chronic cases, activates carcinogenic components. Probiotics have increasingly attracted the attention of researchers in order to understand their action in the intestinal microbiota, aiding in the prevention and treatment of colorectal cancer. The objective of this study was to evaluate the effect of a probiotic In aggressiveness of the chemically induced colorectal tumor in rats. Twenty-five male Fisher 344 rats, 250 g, receiving ration and water ad libitum, were randomly divided into 5 groups (5 rats/group): GControl, without treatment; GTumor, tumor induction; GTumor + 5FU, tumor induction, 5-fluorouracil applied; GTumor + prob, tumor induction, supplemented with probiotic; GTumor + 5-FU + prob, tumor induction, applied 5-fluorouracil, supplemented with probiotic. For tumor induction, the animals received four intraperitoneal injections of the carcinogen 1.2-dimethylhidrazine (DMH) at the dose of 20 mg/kg body weight, being two applications per week, for four consecutive week. A 15-day interval was given and DMH applications were repeated for another four week. After 5 weeks of the last dose of the carcinogen, the treatment was initiated for ten consecutive weeks, applying a weekly dose of 15 mg/kg body weight of 5-fluorouracil, Intraperitoneal route and commercial probiotic containing Lactobacillus and Bifidobacterium at the dose of 1x109 UFC, administered by gavage, daily. Datas were analyzed by the analysis of variance One Way and the averages compared by the test of Dunnett. Used Software Statistical GraphPad Prism. The histopathologic analyses evaluated by the Chi-square ratio test. It was considered type-I error of 5% as statistically significant. Compared to the GTumor, the GTumor + prob (P < 0,0373) and GTumor + 5-FU + prob (P < 0,0003) showed attenuating effect on the aggressiveness of the colorectal tumor, with a reduction in the count of Aberrant Crypts Foci; and lower percentage of malignant neoplastic lesions in the GTumor + prob (40% of low-grade tubular adenoma, 40% of carcinoma in situ, 20% of low-grade adenocarcinoma) and GTumor + 5-FU + prob (40% of low-grade tubular adenoma and 60% of carcinoma in situ). The suplementation with probiotic has the potential to decrease the formation of aberrant crypts and mitigate the progression of tumor malignancy, potentializing the antitumor effect of 5-fluorouracil chemotherapy in the colic segments. / O câncer colorretal (CCR) acomete aproximadamente um milhão de pessoas por ano, considerado a segunda causa de morte mais comum entre mulheres e a terceira mais prevalente em homens. Os fatores de risco incluem as síndromes genéticas; doenças inflamatórias intestinais; história familiar; sedentarismo; obesidade, alimentação pobre em fibras, rica em gorduras saturadas, alimentos defumados ou embutidos, carne vermelha em excesso (>300g/sem), modo de preparação em altas temperaturas e na brasa; medicamentos; tabagismo e bebida alcoólica em excesso. Esses fatores levam a alteração da microbiota intestinal a qual é colonizada por bactérias patogênicas capazes de provocar uma resposta inflamatória local que, em casos crônicos, ativam componentes cancerígenos. Os probióticos têm atraído cada vez mais a atenção de pesquisadores com o intuito de compreender a sua ação na microbiota intestinal, auxiliando na prevenção e tratamento do câncer colorretal. O objetivo desse estudo foi avaliar o efeito de um probiótico na agressividade do tumor colorretal induzido quimicamente em ratos. Vinte e cinco ratos machos Fisher 344, 250 g, recebendo ração e água ad libitum, foram divididos aleatoriamente em 5 grupos (5 ratos/grupo): GControle, sem tratamento; GTumor, indução do tumor; GTumor+5FU, indução do tumor, aplicado 5-Fluorouracil; GTumor+Prob, indução do tumor, suplementado com probiótico; GTumor+5-FU+Prob, indução do tumor, aplicado 5-Fluorouracil, suplementado com probiótico. Para indução do tumor colorretal, os animais receberam quatro injeções intraperitoneais do carcinógeno 1,2-dimetilhidrazina (DMH) na dose de 20 mg/kg de peso corporal, sendo duas aplicações por semana, durante quatro semanas consecutivas. Deu-se um intervalo de 15 dias e as aplicações de DMH foram repetidas por mais quatro semanas. Após 5 semanas da última dose do carcinógeno, iniciou-se o tratamento por dez semanas consecutivas, com 5-Fluorouracil: uma dose de 15 mg/kg por semana, via intraperitoneal e probiótico comercial: 1x109 UFC, diariamente, por gavagem. Os dados foram analisados pela Análise de Variância One Way e as médias comparadas pelo teste de Dunnett. Utilizado software estatístico GraphPad Prism. As análises histopatológicas avaliadas pelo teste de proporção Qui-quadrado. Foi considerado erro tipo-I de 5% como estatisticamente significante. Comparados com o GTumor, o GTumor+Prob (p<0,0373) e GTumor+5-FU+Prob (p<0,0003) exibiram efeito atenuante na agressividade do tumor colorretal obervando redução na contagem de Focos de Criptas Aberrantes; e menor porcentagem de lesões neoplásicas malignas no GTumor+Prob (40% de adenoma tubular de baixo grau, 40% de carcinoma in situ, 20% de adenocarcinoma de baixo grau) e GTumor+5-FU+Prob (40% de adenoma tubular de baixo grau e 60% de carcinoma in situ). Concluimos que a suplementação com probiótico tem potencial para diminuir a formação de criptas aberrantes e amenizar a progressão da malignidade do tumor, potencializando o efeito antitumoral da quimioterapia com 5-Fluorouracil nos segmentos cólicos.

In an experiment to understand colon carcinogenesis, all animals were exposed to a carcinogen while half the animals were also exposed to radiation. Spatially, we measured the existence of aberrant crypt foci (ACF), namely morphologically changed colonic crypts that are known to be precursors of colon cancer development. The biological question of interest is whether the locations of these ACFs are spatially correlated: if so, this indicates that damage to the colon due to carcinogens and radiation is localized. Statistically, the data take the form of binary outcomes (corresponding to the existence of an ACF) on a regular grid. We develop score??type methods based upon the Matern and conditionally autoregression (CAR) correlation models to test for the spatial correlation in such data, while allowing for nonstationarity. Because of a technical peculiarity of the score??type test, we also develop robust versions of the method. The methods are compared to a generalization of Moran??s test for continuous outcomes, and are shown via simulation to have the potential for increased power. When applied to our data, the methods indicate the existence of spatial correlation, and hence indicate localization of damage. Assuming that there are correlations in the locations of the ACF, the questions are how great are these correlations, and whether the correlation structures di?er when an animal is exposed to radiation. To understand the extent of the correlation, we cast the problem as a spatial binary regression, where binary responses arise from an underlying Gaussian latent process. We model these marginal probabilities of ACF semiparametrically, using ?xed-knot penalized regression splines and single-index models. We ?t the models using pairwise pseudolikelihood methods. Assuming that the underlying latent process is strongly mixing, known to be the case for many Gaussian processes, we prove asymptotic normality of the methods. The penalized regression splines have penalty parameters that must converge to zero asymptotically: we derive rates for these parameters that do and do not lead to an asymptotic bias, and we derive the optimal rate of convergence for them. Finally, we apply the methods to the data from our experiment.

In an experiment to understand colon carcinogenesis, all animals were exposed to a carcinogen while half the animals were also exposed to radiation. Spatially, we measured the existence of aberrant crypt foci (ACF), namely morphologically changed colonic crypts that are known to be precursors of colon cancer development. The biological question of interest is whether the locations of these ACFs are spatially correlated: if so, this indicates that damage to the colon due to carcinogens and radiation is localized. Statistically, the data take the form of binary outcomes (corresponding to the existence of an ACF) on a regular grid. We develop score??type methods based upon the Matern and conditionally autoregression (CAR) correlation models to test for the spatial correlation in such data, while allowing for nonstationarity. Because of a technical peculiarity of the score??type test, we also develop robust versions of the method. The methods are compared to a generalization of Moran??s test for continuous outcomes, and are shown via simulation to have the potential for increased power. When applied to our data, the methods indicate the existence of spatial correlation, and hence indicate localization of damage. Assuming that there are correlations in the locations of the ACF, the questions are how great are these correlations, and whether the correlation structures di?er when an animal is exposed to radiation. To understand the extent of the correlation, we cast the problem as a spatial binary regression, where binary responses arise from an underlying Gaussian latent process. We model these marginal probabilities of ACF semiparametrically, using ?xed-knot penalized regression splines and single-index models. We ?t the models using pairwise pseudolikelihood methods. Assuming that the underlying latent process is strongly mixing, known to be the case for many Gaussian processes, we prove asymptotic normality of the methods. The penalized regression splines have penalty parameters that must converge to zero asymptotically: we derive rates for these parameters that do and do not lead to an asymptotic bias, and we derive the optimal rate of convergence for them. Finally, we apply the methods to the data from our experiment.

Dietary fiber (DF) consumption is related with several healthy benefits such as the decreasing risk of colon cancer development. The DF is not digested by the digestive enzymes and reach to colon where is fermented by the colonic microbiota. The fermentation process releases metabolites as short chain fatty acids (SCFA) such as butyrate, propionate and acetate. Besides the fermentation process, the DF can directly interact with intestinal epithelial cells inducing mechanism that can also be related with the associated DF consumption benefits. The lack of information regarding DF and colon cancer are due to the complexity of both the cancer and the DF structure. The papayas DF are derived from the fruit cell wall, and they are probably naturally modified during ripening through a massive polysaccharide hydrolysis, because papayas show a very fast pulp softening. Due to the lack of information about DF and their beneficial effects to human health as well as the possibility of the natural papaya ripening to modifying the DF presented in the fruit pulp, the present thesis had as the primary objectives: 1) to evaluate how the cell-wall degrading enzymes affect the fruit cell wall solubilization and molecular weight; 2) to investigate the direct effects of the papaya pectin derived from unripe to ripe papayas in cancer cell lines, in galectin-3 interaction and in HEK cells expressing pattern recognition receptors (PRR); 3) to evaluate the human colonic in vitro fermentation using DF from unripe and ripe papayas as substrates; 4) to conduct an in vivo experiment using rats with pre-neoplastic colon lesions while receiving a diet with DF from unripe and ripe papayas. The endopolygalacturonases were the main enzymes acting on the solubilizing papaya cell wall pectin affecting both the papaya firmness and pectin structure. Overall, the papayas DF showed a ripening dependent structureeffects. In the cancer cell lines experiments, the ripe papayas pectin showed a more pronounced effects in inducing cancer cell death, inhibiting cancer cells migration and aggregation, activating PRR as toll-like receptors and inhibiting the pro-metastatic protein galectin-3. The DF from papayas also showed different aspects in colonic in vitro fermentation regarding the DF utilization by the bacteria and the bacteria abundance profile. Lastly, the animals receiving the diet with the DF from ripe papayas had less aberrant crypt foci in colon than the animals that received the DF from unripe papayas or cellulose (AIN-93G DF). Therefore, the study of papaya DF was carried out both during papaya ripening and its biological effects in vitro and in vivo, generating unprecedented results relating the endogenous biochemical changes of the fruits during maturation with the possible beneficial effects of their ingestion for health human. / O consumo de fibras alimentares (FA) está relacionado com vários benefícios à saúde como a diminuição no risco do desenvolvimento de câncer de cólon. A FA não é digerida pelas enzimas digestivas do trato gastrointestinal sendo fermentada pela microbiota intestinal do cólon. Como subproduto do processo de fermentação há a liberação de ácidos graxos de cadeia curta (SCFA) - como o butirato, o propionato e o acetato. Além do processo de fermentação, a FA pode interagir diretamente com as células epiteliais do intestino, induzindo mecanismos que também podem estar relacionados com os benefícios associados ao consumo de FA. A falta de informação sobre a FA e o câncer de cólon é, em partes, devido à complexidade de ambos, tanto do câncer quanto da estrutura da FA. As FA do mamão papaia são derivadas da parede celular da fruta apresentando diferentes estruturas dependendo do ponto de amadurecimento do fruto. Esse fato ocorre, pois, durante o amadurecimento do mamão papaia, existe uma extensa hidrólise dos polissacarídeos presentes na parede celular, diminuindo rapidamente a firmeza da polpa do fruto. Devido à falta de informações sobre FA e seus efeitos benéficos à saúde humana que são dependentes da sua estrutura, bem como a possibilidade do amadurecimento do mamão papaia naturalmente modificar as FA presentes na polpa dos frutos, a presente tese teve como principais objetivos: 1) avaliar como as enzimas que degradam a parede celular do mamão papaia afetam a solubilização e o peso molecular da parede celular do fruto; 2) investigar os efeitos diretos da pectina derivada de mamões verdes e maduros em linhagens de células de câncer, na interação com a galectina-3, e em células do tipo HEK que expressam receptores de reconhecimento de padrões (RRP); 3) avaliar a fermentação colônica humana in vitro utilizando as FA de mamões verdes e maduros; 4) avaliar em ratos com lesões pré-neoplásicas no cólon o efeito do consumo de ração com ou sem FA de mamões papaias verdes e maduros. As endopoligalacturonases foram relacionadas como as principais enzimas que atuam solubilizando a pectina da parede celular do mamão, afetando tanto a firmeza da polpa do fruto quanto a solubilização da pectina durante o amadurecimento. De modo geral, as FA dos mamões exerceram um efeito estruturadependente de acordo com a maturação do fruto. Nos experimentos utilizando linhagens de células de câncer, a pectina do mamão papaia maduro apresentou efeitos mais pronunciados na indução da morte e na inibição da migração e da agregação das células, bem como ativando os RRP, como por exemplo, os receptores do tipo toll-like, além de inibir a proteína pró-metastática galectina-3. As FA dos mamões também apresentaram diferentes resultados na fermentação colônica in vitro quanto à utilização das FA pelas bactérias do intestino, e também no perfil de crescimento dessas bactérias. Por fim, os animais que receberam a dieta com as FA dos mamões maduros apresentaram menor incidência de focos de criptas aberrantes do que os animais que receberam as FA provenientes de mamões verdes ou de celulose (FA da ração AIN-93G). Portanto, o estudo das FA dos mamões foi efetuado tanto durante o amadurecimento dos mamões quanto dos seus efeitos biológicos in vitro e in vivo, tendo gerado resultados inéditos relacionando as alterações bioquímicas endógenas dos frutos durante o amadurecimento com os possíveis efeitos benéficos da sua ingestão para a saúde humana.

O composto estudado neste trabalho foi o corante comercial CI Disperse Blue 291 (DB291), que contém o aminoazobenzeno 2-[(2-bromo-4,6-dinitrofenil)azo]-5-(dietilamino)-4-metoxiacetanilida. Esse produto é um azo-corante disperso usado largamente pelas indústrias têxteis para o tingimento de poliéster e pode ser encontrado em ambientes aquáticos oriundo da descarga de efluentes industriais, podendo levar à exposição de humanos por meio da ingestão de água ou alimentos contaminados. Portanto, faz-se importante a avaliação toxicológica do DB291. Este produto apresentou atividade mutagênica para linhagens de Salmonella typhimurium que possuem alta expressão das enzimas nitrorredutase e &#927;-acetiltransferase. Tais enzimas também são expressas pelas bactérias da flora intestinal humana e de roedores e, desempenham importante papel na biotransformação de substâncias presentes na luz intestinal. O objetivo deste trabalho foi investigar a atividade do corante DB291 na indução de lesões pré-neoplásicas no cólon de ratos, avaliada pelo teste do cometa e pelo desenvolvimento de focos de criptas aberrantes (FCAs). Resultados com 2, 8, 16 e 24 semanas de tratamento demonstraram que o DB291 não foi capaz de induzir FCAs em ratos tratados por gavage com a dose de 50mg/kg de peso corpóreo, três vezes por semana em dias alternados. Entretanto, resultados com o teste do cometa demonstraram que o corante foi capaz de causar danos ao DNA das células da mucosa do cólon de ratos tratados por via intra-retal. Estes resultados sugerem que o DB291 possui atividade genotóxica in vivo. Considerando a resposta genotóxica para o teste do cometa, a alta atividade mutagênica no teste Salmonella microssoma e o recente relato de que o DP291 causou danos em células de fígado humano (HepG2), faz-se necessário a realização de testes de carcinogênese de longa duração para avaliação segura do seu potencial carcinogênico, não somente em cólon, mas em outros órgãos tais como fígado e bexiga. / The commercial disperse dye product CI Disperse Blue 291 , which contain the aminoazobenzene 2-[(2-bromo-4,6-dinitrophenyl)azo]-5-(diethylamino)-4-methoxyacetanilide (CAS registry no. 56548-64-2) is used for polyester fibers dyeing. It can be released in the aquatic environment through the discharge of industrial effluents. Humans can be exposed through the consumption of water and food contaminated with this product therefore its toxicological properties are important to be evaluated. This product showed elevated mutagenic activity with nitroreductase and &#927;-acetyltransferase overproducing Salmonella strains. These enzymes are also expressed by human intestinal microflora, making intestines a possible target organ to the development of cancer after exposure to this product. The aim of this study was to investigate the effects of the commercial disperse dye product containing the CI Disperse Blue 291 on rat colon carcinogenesis, evaluated by the single cell gel assay (comet assay) and by aberrant crypt foci development. Results within different experimental periods showed the DB291 were not able to induce preneoplastic lesions in the colon of rats orally treated with 50mg/kg b.w., three times a week. The DB291 induced damages in the DNA of the rats colon mucosa, evaluated by the comet assay. These data indicate that the OB291 showed genotoxic activity in the colon mucosa cells. Considering these results, the mutagenic activity with Salmonella test and the recent data that the OB291 presents toxicity to human liver cells (HepG2), further long time carcinogenesis assays are needed to security evaluation of its carcinogenic potential, not only in colon, but also another organs like liver and kidney.

O composto estudado neste trabalho foi o corante comercial CI Disperse Blue 291 (DB291), que contém o aminoazobenzeno 2-[(2-bromo-4,6-dinitrofenil)azo]-5-(dietilamino)-4-metoxiacetanilida. Esse produto é um azo-corante disperso usado largamente pelas indústrias têxteis para o tingimento de poliéster e pode ser encontrado em ambientes aquáticos oriundo da descarga de efluentes industriais, podendo levar à exposição de humanos por meio da ingestão de água ou alimentos contaminados. Portanto, faz-se importante a avaliação toxicológica do DB291. Este produto apresentou atividade mutagênica para linhagens de Salmonella typhimurium que possuem alta expressão das enzimas nitrorredutase e &#927;-acetiltransferase. Tais enzimas também são expressas pelas bactérias da flora intestinal humana e de roedores e, desempenham importante papel na biotransformação de substâncias presentes na luz intestinal. O objetivo deste trabalho foi investigar a atividade do corante DB291 na indução de lesões pré-neoplásicas no cólon de ratos, avaliada pelo teste do cometa e pelo desenvolvimento de focos de criptas aberrantes (FCAs). Resultados com 2, 8, 16 e 24 semanas de tratamento demonstraram que o DB291 não foi capaz de induzir FCAs em ratos tratados por gavage com a dose de 50mg/kg de peso corpóreo, três vezes por semana em dias alternados. Entretanto, resultados com o teste do cometa demonstraram que o corante foi capaz de causar danos ao DNA das células da mucosa do cólon de ratos tratados por via intra-retal. Estes resultados sugerem que o DB291 possui atividade genotóxica in vivo. Considerando a resposta genotóxica para o teste do cometa, a alta atividade mutagênica no teste Salmonella microssoma e o recente relato de que o DP291 causou danos em células de fígado humano (HepG2), faz-se necessário a realização de testes de carcinogênese de longa duração para avaliação segura do seu potencial carcinogênico, não somente em cólon, mas em outros órgãos tais como fígado e bexiga. / The commercial disperse dye product CI Disperse Blue 291 , which contain the aminoazobenzene 2-[(2-bromo-4,6-dinitrophenyl)azo]-5-(diethylamino)-4-methoxyacetanilide (CAS registry no. 56548-64-2) is used for polyester fibers dyeing. It can be released in the aquatic environment through the discharge of industrial effluents. Humans can be exposed through the consumption of water and food contaminated with this product therefore its toxicological properties are important to be evaluated. This product showed elevated mutagenic activity with nitroreductase and &#927;-acetyltransferase overproducing Salmonella strains. These enzymes are also expressed by human intestinal microflora, making intestines a possible target organ to the development of cancer after exposure to this product. The aim of this study was to investigate the effects of the commercial disperse dye product containing the CI Disperse Blue 291 on rat colon carcinogenesis, evaluated by the single cell gel assay (comet assay) and by aberrant crypt foci development. Results within different experimental periods showed the DB291 were not able to induce preneoplastic lesions in the colon of rats orally treated with 50mg/kg b.w., three times a week. The DB291 induced damages in the DNA of the rats colon mucosa, evaluated by the comet assay. These data indicate that the OB291 showed genotoxic activity in the colon mucosa cells. Considering these results, the mutagenic activity with Salmonella test and the recent data that the OB291 presents toxicity to human liver cells (HepG2), further long time carcinogenesis assays are needed to security evaluation of its carcinogenic potential, not only in colon, but also another organs like liver and kidney.