No description available.

Submitted by isabela.moljf@hotmail.com (isabela.moljf@hotmail.com) on 2017-05-19T13:37:35Z No. of bitstreams: 1 luizgustavodeoliveira.pdf: 3109049 bytes, checksum: 4df3b04529f2b0980313cfda47b84ab7 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-05-19T14:46:00Z (GMT) No. of bitstreams: 1 luizgustavodeoliveira.pdf: 3109049 bytes, checksum: 4df3b04529f2b0980313cfda47b84ab7 (MD5) / Made available in DSpace on 2017-05-19T14:46:00Z (GMT). No. of bitstreams: 1 luizgustavodeoliveira.pdf: 3109049 bytes, checksum: 4df3b04529f2b0980313cfda47b84ab7 (MD5) Previous issue date: 2013-03-22 / Doenças inflamatórias intestinais, entre elas colite ulcerativa e doença de Crohn, compreendem um amplo espectro de afecções que apresentam em comum inflamação crônica do trato gastrointestinal. Colite ulcerativa afeta exclusivamente o cólon e o reto, possui etiologia ainda pouco conhecida podendo estar relacionada com fatores ambientais, genéticos e de resposta imune. O tratamento se baseia em medicamentos como aminossalicilatos, glicocorticóides e imunossupressores, porém seus efeitos colaterais atrapalham a adesão do paciente ao tratamento por longos períodos. Condroitim sulfato (CS) e glucosamina (GlcN) são atualmente indicados para o tratamento de doenças inflamatórias, como a osteoartrite, principalmente por apresentarem efeito anti-inflamatório ao diminuírem a ação do fator de transcrição NF-kB diminuindo a expressão de metaloproteases (MMP), TNF-α, iNOS entre outros mediadores inflamatórios. O objetivo deste trabalho foi analisar os efeitos da associação de CS e GlcN na colite ulcerativa experimental induzida por dextran sulfato de sódio (DSS) em ratos Wistar. Para isso foram avaliados o índice de atividade da doença (IAD), parâmetros hematológicos e bioquímicos, morfológicos e a atividade de MMP-2 e -9 da matriz extracelular no intestino grosso, concentração de NO tecidual e concentração de glicosaminoglicanos. Os animais foram divididos em quatro grupos: (1) controle, (2) controle + CS/GlcN, (3) DSS , (4) DSS + CS/GlcN. Observamos que o tratamento com CS/GlcN melhorou a severidade da colite aguda em ratos, verificado pela redução do score histológico e melhora de parâmetros hematológicos. CS/GlcN também reduziu a destruição de células caliciformes observados pelo azul de alcian, bem como a produção de óxido nítrico, a atividade de mieloperoxidase e metaloproteases, principalmente de MMP-9. Além disso, foi observado uma redução na concentração de GAGs total no grupo DSS + CS/GlcN quando comparado ao grupo DSS. Portanto, a administração de CS/GlcN apresentou melhoras em alguns dos parâmetros avaliados principalmente na atividade de MMP-9, mostrando um potencial destes compostos para futura utilização no tratamento dessa patologia. / Inflammatory bowel disease, including ulcerative colitis and Crohn's disease comprising a broad spectrum of diseases those have in common chronic inflammation of the gastrointestinal tract. Ulcerative colitis affects only the colon and rectum, has still poorly understood etiology and this could may be related to environmental factors, genetic and immune response. Treatment is based on drugs as aminosalicylates, immunosuppressants and glucocorticoids, but its side effects hinder patient compliance with treatment for long periods. Chondroitin sulphate (CS) and glucosamine (GlcN) are currently indicated for treatment of inflammatory diseases such as osteoarthritis, mainly because of the anti-inflammatory effect by decreasing the activity of transcription factor NF-kB and decreasing the expression of metalloproteases (MMP), TNF-α, iNOS and other inflammatory mediators. The objective of this study was to analyze the effects of the combination of CS and GlcN in experimental ulcerative colitis model induced by dextran sulfate sodium (DSS) in rats. To do so we evaluated the disease activity index (DAI), haematological and biochemical parameters, morphological changes and activity of MMP-2 and -9, NO and glycosaminoglycans concentration in the large intestine. Animals were divided into four groups: (1) control, (2) control + CS / GlcN, (3) DSS-induced colitis, (4) DSS + CS / GlcN. We observed that treatment with CS/GlcN improved the severity of acute colitis in rats verified by histological score reduction and improvement in hematological parameters. CS/GlcN also reduced goblet cells destruction observed by alcian blue, as well as nitric oxide production, the activity of myeloperoxidase and metalloproteases, especially MMP-9. Moreover, we observed a reduction in the concentration of total GAG + DSS group CS / GlcN when compared to DSS. Therefore, administration of CS/GlcN showed improvements in some of the parameters evaluated mainly on the activity of MMP-9, showing a potential future use of these compounds for the treatment of this pathology.

Les polyphénols, micronutriments abondants dans notre alimentation, sont bien connus pour leurs propriétés antioxydantes et anti-inflammatoires et leur consommation a été associée à un moindre risque de maladies chroniques (maladies cardiovasculaires, cancers…). Ces composés suscitent un intérêt croissant dans le domaine de la santé digestive. En effet, les polyphénols sont faiblement absorbés au niveau de l’intestin grêle et sont présents en quantité relativement importante dans le côlon. Les polyphénols et leurs métabolites pourraient donc exercer des effets bénéfiques à ce niveau. Des études expérimentales récentes suggèrent que les polyphénols pourraient aider à prévenir ou retarder la progression de l’inflammation colique. Le raisin est l’un des fruits les plus riches en polyphénols. Divers co-produits du raisin ont montré des effets bénéfiques vis-à-vis de différentes situations d'inflammation, effets souvent attribués à leur richesse en composés polyphénoliques. Les objectifs de cette thèse étaient tout d’abord d’évaluer l’impact du régime de base sur le développement de l’inflammation colique induite par le sulfate de dextran sodique (DSS) chez le rat (1) puis d’évaluer les effets d’une supplémentation nutritionnelle en extraits de marc de raisin (EMR) riches en polyphénols dans la prévention de l’inflammation colique induite par le DSS (2). Pour cela, des rats Wistar ont été nourris ad libitum durant 21 jours avec un régime standard ou un régime semi-synthétique (1) ou les animaux ont été nourris avec un régime semi-synthétique supplémenté ou non avec un EMR (2). Dans tous les cas, l’inflammation colique a été induite par administration de DSS à 4% dans l’eau de boisson pendant les 7 derniers jours de l’expérimentation. Les effets ont été évalués au niveau colique par analyse histologique, détermination de différents marqueurs de l'inflammation et de la défense antioxydante et évaluation de l'expression de différents gènes impliqués dans l’inflammation et le stress oxydant.La consommation préventive de trois EMRs, issus de deux cépages différents (Alicante et Pinot) exerce des effets bénéfiques sur le développement de l’inflammation colique induite par le DSS. Globalement, la consommation à titre préventif d’EMRs prévient la perte de poids, retarde l’apparition des symptômes de la maladie et limite le développement des atteintes tissulaires induites par le DSS. Les EMRs atténuent l’inflammation comme en témoigne la diminution de l’activité de la MPO et le maintien des taux coliques en cytokines pro-inflammatoires au niveau des animaux témoins. De plus, ces EMRs modulent les activités des enzymes antioxydantes. Les EMRs limitent également la surexpression de plusieurs gènes impliqués dans la réponse inflammatoires et le stress oxydant (COX-2, iNOS, ICAM-1, MMP-9…). De plus, nous avons montré que les EMRs provenant du cépage Alicante exercent des effets protecteurs plus marqués que l’EMR Pinot.Ainsi, ces résultats soulignent d’une part l’influence du régime alimentaire de base dans l’induction de l’inflammation colique. D’autre part, la consommation à titre préventif d’EMRs exerce des effets protecteurs sur le développement de l'inflammation colique induite par le DSS via la modulation de marqueurs de l’inflammation et de la défense antioxydante. Ces résultats pourraient permettre d’envisager de nouvelles stratégies nutritionnelles dans la prévention des maladies inflammatoires de l’intestin. / Polyphenols are abundant micronutrients in plant foods, where they have been associated with lower risk of chronic diseases from cancer to cardiovascular disease. The beneficial health effects of polyphenols have been attributed to their antioxidant and anti-inflammatory properties. Several studies point to a promising role of these micronutrients in inflammatory bowel disease (IBD), as given that a large fraction of dietary polyphenols reach the colon, polyphenols and their metabolites could exert beneficial effects locally at this level. Recent experimental data suggest that polyphenols could help prevent or delay the progression of intestinal inflammation. Grape is one of the richest sources of polyphenols, and various grape products have demonstrated beneficial effects in various chronic diseases. These effects are often attributed to grape polyphenolic compounds.This thesis aimed (1) to evaluate the impact of purified and non-purified basal diets on the development of dextran sodium sulfate (DSS)-induced colitis in the rat, then (2) to evaluate the effects of preventive consumption of polyphenol-rich red grape pomace extracts (GPEs) on DSS-induced colitis. Rats were fed for 21 days with (1) a non-purified or purified diet or (2) GPE-enriched purified diet, and colitis was induced by DSS administration in drinking water (4% w/v) during the last 7 days of the experimental design. The effects on colitis development were assessed by histological analysis, determination of various markers of inflammation and oxidative stress, and evaluation of the expression of various genes implicated in this disorder.DSS induced a more marked colitis in rats receiving the purified diet than the non-purified diet. Indeed, rats receiving the purified diet, the inflammation was characterized by decreased appetite and weight gain, early onset of disease (diarrhea and rectal bleeding), and colon shortening. In rats fed the purified diet, DSS also induced marked histological colonic damage and increased MPO activity. In these animals, DSS also modulated oxidative status by affecting antioxidant enzyme activities. Furthermore, DSS-induced inflammation was associated with increased pro-inflammatory cytokine levels and decreased anti-inflammatory cytokine levels in colonic tissue, together with upregulation of the expression of various genes (iNOS, ICAM-1 and MMP-9).Preventive consumption of three GPEs from two different grape varieties (Alicante and Pinot) showed beneficial effects on DSS-induced colitis development. Overall, preventive dietary GPE supplementation delayed the onset of colitis symptoms and limited the extent of weight loss and colonic mucosa damage. GPE administration reduced inflammation (as evidenced by a decrease in MPO activity) and kept colonic pro-inflammatory cytokines at near-control levels. In addition, the three GPEs modulated antioxidant enzyme activities and limited the overexpression of several genes involved in DSS-induced inflammatory response and oxidative stress (COX-2, iNOS, ICAM-1, MMP-9). Moreover, Alicante-variety GPEs exerted stronger protective effects than Pinot-variety GPEs.These results highlighted (1) the influence of basal diet on induction of colonic inflammation and (2) that preventive consumption of GPEs exerted protective effects against colitis development by modulating inflammatory processes and oxidative stress markers. These findings open up perspectives for new preventive nutritional strategies in colonic inflammation management.