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novo_r_dr_botfm.pdf: 1015453 bytes, checksum: 101fa6a393e4fe3aea61177cb99fc2d5 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Em estudo anterior realizado em nosso laboratório ratos expostos à fumaça de cigarro apresentaram menor mortalidade após infarto agudo do miocárdio em relação ao grupo controle. Entretanto a mortalidade aumentou nos ratos fumantes quando receberam β-caroteno. Não se sabe qual o mecanismo da diminuição de mortalidade nos animais fumantes. Formulamos a hipótese de que a fumaça de cigarro induziria estresse oxidativo que causaria efeito tipo precondicionamento cardíaco. O efeito tipo precondicionamento diminuiria a comunicação intercelular pelas junções comunicantes. A suplementação da dieta com β-caroteno inibiria os efeitos provenientes da exposição à fumaça de cigarro. Foram estudados ratos Wistar, distribuídos em 4 grupos: grupo controle (C) - formado por 30 animais, que receberam a dieta usada de rotina em nosso laboratório; 2) grupo β-caroteno (BC) - composto por 28 animais que receberam β-caroteno (na forma de cristal adicionado e misturado à dieta) na dose de 500 mg de β-caroteno/kg de dieta; 3) grupo exposto à fumaça de cigarro (EFC) composto por 28 animais, que receberam a dieta usada de rotina em nosso laboratório e foram expostos ao cigarro; 4) grupo β-caroteno/EFC (BC/EFC) - formado por 28 animais que receberam o β-caroteno na mesma forma que o grupo BC e foram expostos à fumaça de cigarro. A suplementação com β- caroteno e a EFC foram realizados simultaneamente, até que ratos, com peso inicial de 100g, 82 atingissem peso corpóreo de 200-250g. / In previous study performed in our laboratory, we observed which the mortality rates were lower in exposure to tobacco smoke rats than in control rats. Moreover, when the exposure to tobacco smoke rats received β-carotene supplementation this reduction of mortality was abolished. The mechanisms of lower mortality in smokers are unknown. In this context we formulated the hypothesis of that the exposure to tobacco smoke produces oxidative stress which would induce precondictioning-like effect. This effect would cause reduction of gap junctional intercellular communication. The supplementation with β-carotene would abolish the effect of the tobacco smoke. Male Wistar rats were allocated in four experimental groups: 1) Control group (C), n=30: control rats were fed a standard diet without exposure tobacco smoke; 2) β-carotene group (BC), n= 28: rats fed the same diet supplemented with 500 mg of β-carotene/kg diet (Sigma) milled in the feed; 3) Exposure to tobacco smoke group (ETS), n=28: rats exposed to tobacco smoke; 4) BC/ETS group (BC/ETS), n=28: rats exposed to tobacco smoke plus BC supplementation. The BC supplementation and tobacco smoke exposure were performed simultaneously until the rats weighed 200 to 250 g (approximately 5 weeks). After this period of treatment the rats were killed and the serum, livers and hearts storaged to -80°C for study of: 1) intercellular communication by immunohistochemistry and western blotting for Cx43; 2) oxidative stress by dosages of reduced glutathione (GSH), oxidized glutathione (GSSG) and lipid 85 hidroperoxides; 3) cardiac remodeling by morphometrical and histological (picro sirius red and hematoxilin-eosin) analyses; 4) biochemical study by BC analysis in serum end tissues. The statistical analysis was performed by t students test for BC levels and two way ANOVA for the rest of variables.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.unesp.br:11449/102654 |
| Date | 26 February 2008 |
| Creators | Novo, Rosangela [UNESP] |
| Contributors | Universidade Estadual Paulista (UNESP), Paiva, Sergio Alberto Rupp de [UNESP], Zornoff, Leonardo Antonio Mamede [UNESP] |
| Publisher | Universidade Estadual Paulista (UNESP) |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | Portuguese |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Format | 82 f. |
| Source | Aleph, reponame:Repositório Institucional da UNESP, instname:Universidade Estadual Paulista, instacron:UNESP |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | -1, -1, -1 |
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