Lesões pré-neoplásicas, perfil lipídico, marcadores inflamatórios e aspecto histológico intestinal de ratos Wistar alimentados com dietas à base de diferentes óleos

• Autor(a) principal: Rosa, Damiana Diniz
• Data de Publicação: 2010
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/2730
• topic: Óleo de peixe; Óleo de linhaça; Fish oil; Flaxseed oil; CNPQ::CIENCIAS DA SAUDE::NUTRICAO

The action of oils and fats in human nutrition has been amply studied and discussed in recent decades. Attention has been given to the nutritional quality of these oils, where quantity and composition of fatty acids is important. Essential fatty acids are important due to the their pharmacological roles and as mediators of inflammatory reactions, directly related to immunological resistance, thromboticprocesses and neoplastic diseases. Experimental studies support the hypothesis that &#969;6 fatty acids contribute to progressive development of neoplastic wounds while &#969;3 fatty acids possess a protective action. The objective of the present study was to evaluate the effects of adding different oils to the diet (soy, olive, fish, flaxseed) for prevention of preneoplastic wounds on the colon of Wistar rats. Also evaluated was its effect on the lipid profile, inflammatory markers, migration of inflammatory cells and histological analysis of intestinal mucus of the animals. Two experiments were performed. In the first, and exploratory study was performed on adult Wistar rats fed with normolipid diets AIN-93M (4g/100g diet). The animals were divided in four groups and received diets based on soy (control), olive, fish and flaxseed oil ad libitum, for a period of 9 weeks. Biochemical parameters (total cholesterol, HDL-cholesterol and triglycerides), number of lymphocytes in the intestinal mucus and morphometry of the villi were evaluated. The group fed with fish oil presented the lowest values of total cholesterol, HDL-cholesterol and triglycerides (p<0.05). The grouptreated with fish and olive oil presented the best preservation of the intestinal villi. A smaller deposition of lymphocytes in the ileal mucus was verified in the flaxseed group (p<0.001). From these results a second experiment was developed with the intention of confirming the hypothesis of the chemopreventive effect of the oils (olive, fish and flaxseed) present in the normolipid diets and now administered to the animals induced to pre-neoplastic wounds. In this experiment, adult Wistar rats were treated with 1,2-dimethylhydrazine, at the dose of 40 mg/kg body weight, maintained in the same experimental conditions as before. The fatty acid profiles of the serum, xvii hepatic tissue, intra-abdominal fat and in the feces were evaluated; investigating the presence of bioactive amines in the hepatic tissue, inflammatory mediators (IL-8, MCP-1 and TGF-&#946;) in the colonial mucus, and counting the lymphocytes in the intestinal mucus and mophometry of the villi. It was verified that the group fed with fish oil presented greater levels of EPA (p=0.004) and DHA (p<0.001) in the liver and greater levels of linolenic acid (p=0.003) and EPA (p=0.011) in the intra-abdominal adipose tissue in relation to the other treatments. In these tissues, a lower &#969;6/&#969;3 ratio was verified in the groups fed with polyunsaturated oils (fish and flaxseed). Greater levels of &#945;-linolenic acid were excreted by the flaxseed group (p=0.014). No difference was encountered in the number of FCA between the groups fed with the different lipid sources (p>0.05). There was no difference in the expression of IL-8, TGF-&#946;, and MCP-1 in relation to the control (p>0.05). When comparatively evaluating expression of the cytokines, it was verified that the fish oil group expressed two times more TGF-&#946; and eight times less IL-8 in relation to the other treatments. The olive oil group presented lower levels of spermidine (p=0.008) in relation to the other treatments. The group fed with fish oil presented few deposits of lymphocytes in the ileal mucus (p<0.001). A morphmetric analysis showed that the treatments presented height of the villus, depth of the crypt and width of the villi less than that of the control (p<0.001). This study demonstrated that flaxseed, olive and fish oil presented different responses in relation to soy oil on the preservation of intestinal mucus and proliferation of lymphocytes in healthy Wistar rats. In animals treated with carcinogens, the fish oil presented an important protective effect on the colonial mucus. The &#945;-linolenic fatty acids, EPA and DHA present a differential metabolism in relation to incorporation in the hepatic and intra-abdominal tissues, formation of pre-neoplastic wounds and expression of inflammatory cytokines in the colon. Greater incorporation of PUFA from the &#969;3 series in the fish oil group suggests a modular effect on the inflammatory response, in function of the lower migration of lymphocytes in the intestinal mucus of this group.