Please use this identifier to cite or link to this item: https://www.arca.fiocruz.br/handle/icict/35390
Title: Calomys callosus Renger 1830, (Rodentia-Cricetidae): um modelo para o estudo da fibrogênese e da fibroclasia espontânea na infecção pelo Trypanosoma cruzi
Advisor: Andrade, Sonia Gumes
Authors: Santos, Isis Fernandes Magalhães
Affilliation: Universidade Federal da Bahia. Faculdade de Medicina. Salvador, BA, Brasil / Fundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Saúde. Salvador, BA, Brasil.
Abstract: Investigamos a influência de cepas do T. cruzi pertencentes aos diferentes Biodemas (Tipos I, II e II), na evolução da infecção e das lesões e das histopatológicas, no histotropismo e na patogenicidade para C. callosus. Avaliamos através imunofluorescência, utilizando anticorpos monoclonais específicos, contra os componentes da matriz extracelular, a presença dos tipos genéticos do colágeno, de fibronectina e laminina, nas diferentes fases da infecção. Foi investigada por imunomarcação in situ a participação de citocinas pró- inflamatórias e pró-fibrogênicas na patogênese das lesões necrótico-inflamatórias no C. callosus infectado com a cepa Colombiana do T. cruzi. Os animais foram infectados com as cepas de Biodema tipo I (Y) , tipo II (21SF) e tipo III (colombiana) e sacrificados em diferentes períodos pós-infecção de acordo com a cepa, de 7 a 70 dias (à) Secções de coração e de músculo esquelético foram fixadas para avaliação histopatológica e criopreservadas para estudo imunohistoquiímico dos colágenos tipo I, II, Iv, laminina e fibronectina a das citocinas interferon Gama, Fator de Transformação do Crescimento e Fator de Necrose Tumoral. A resposta peculiar observada, indica uma influência dos diferentes Biodemas na evolução da infecção (à) Os componentes da matriz presentes na fase inicila da infecção foram predominantemente fibronectina, laminina e colágeno tipos I, II, IV no coração . No músculo esquelético predominaram os colágenos tipos III e IV (à) Os resultados da imunomarcação de citocinas demonstrou a presença de Fator de Necrose Tumoral, Interferon Gama e fator de Transformação do Crescimento desde o 15º dia até o 40º dia de infecção e desaparecimento total com 65 dias de infecção, exceto o Interferon Gama que esteve presente em células de focos residuais da inflamação nesta fase . Estes resultados indicam que na infecção experimental, o comportamento do C. callosus, reflete uma afinidade por cepas do tipo III ( Zimodema; T. cruzi I), modulando o processo inflamatório, com regressão espontânea da fibrose, independente dos tipos genéticos do colágeno presentes no interstício. Estas obsrvações surgerem que citocinas como Fator de Necrose Tumoral e Interferon Gama estão participando da destruição de parasitas intracelulares e o Fator de Transformação do Crescimento participando da precoce fibrogênese descrita neste modelo, bem como na modulação deste processo, controlando a infecção e resolvendo as lesões fibrótico-inflamatórias.
Abstract: INTRODUCTION: The Calomys callosus, a silvatic reservoir of Trypanosoma cruzi, biologically described and adapted to laboratory, has been used in the study of experimental infection with this parasite. The C. callosus differs from the murine model in the response to the in fection with different strain of T. cruzi, controlling the Infection, with negativatlon of the parasitemia and null mortality. In the present study we investigated the influence of the infection with strains of the different Biodemes (Types I, II and III) on the evolution of the Infection, the histopathological lesions, the histotropism and the pathogenicity, in the mode) of C. callosus. Subsequently, Calomys callosus infected with the Colombian strain of Trypanosoma cruzi were studied with the objective of to characterize by immunofluorescence, using specific monoclonal antibodies, the presence of the different genetic types of collagen, fibronectin and laminin in different phases of the infection. The participation of proinflammatory and pro-fibrogenic cytokines in the pathogenesis of the necrotic-inflammatory lesions were also investigated. MATERIAL AND METHODS: C. callosus were infected respectively with the strains representatives of the three different Biodemes: Type I - Y strain. Type 11-21SF strain (T. cruzi If) and Type III -Colombian strain (T. cruzi I) and sacrificed at different periods post-infection, according with the strain, from 7 to 70 days. For each group, normal C. callosus were also used as controls and paresitemia and mortality of infected groups were evaluated. Sections of the heart and skeletal muscle were processed for histopathologic examination. Immunohistochemical test were performed using cryostat sections incubated with specific antibodies against collagen type 1, III, IV, laminin and fibronectin. The cytokines such as IFN-y, TGF-p and TNF-awere also tested by immunolabelling in situ in cryostat sections of the heart and skeletal muscle. RESULTS: In this model, the peculiar responses observed, points to the influence of different biodemes in the evolution of the infection. The strains Types I and II (Y and 21 SF) determined moderate degree of lesions mostly in the myocardium, with low parasitism, a rapid course and total regression of the lesions until 60 days. Differently, the Colombian strain (Type III), was highly pathogenic and determined necrotic inflammatory lesions in the skeletal muscle and myocardium, corresponding to intracellular parasitism. The immunoisotyping of matritial components showed in the early phase, positive deposits of the matrix components, with predominance of fibronectin, laminin and collagens types 1 and 111 in the myocardium and the presence of collagen types 111 and IV in the skeletal muscle. From the 40*^ day, type IV collagen predominates in the heart. At the late phase of the infection (60*^ to 90*^ days), a clear fragmentation and decrease of all the matrix components were observed. The immunohistochemistry staining, revealed the presence in situ of TNFa, IFNy , and TGFp, detected from 15*^ to 45*^ days postinfection, decreasing of Intensity until complete disappearence in the 65^^ day, except for the IFN -y, which was present into the cells of residual foci of inflammation. CONCLUSION: Findings of the present study indicate that the peculiar behavior of C. callosus when infected with the Colombian strain, could reflect an affinity of Type III strain, Z1 {T.cruzi I), with modulation of the inflammatory process, leading to spontaneous regression of fibrosis independent of the genetic types of col lagen involved in this process. This observations suggest an active participation of cyloklnes in the destruction of intracellular parasites with the participation of TNFa and IFNy. The early fibrogenesis is possibly mediated by the TGFp, that also controls the infection, with resolution of the inflammation and of fibrosis.
Keywords: Chagas disease
Trypanosoma cruzi
Calomys callosus
Fibrosis
Cytokines
Animals Wild
keywords: Doença de Chagas
Trypanosoma cruzi
Calomys callosus
Fibrose
Matrix extracelular
Citocinas
Animais Selvagens
Issue Date: 2003
Publisher: Centro de Pesquisas Gonçalo Moniz
Citation: SANTOS, Isis Fernandes Magalhães. Calomys callosus Renger 1830, (Rodentia-Cricetidae): um modelo para o estudo da fibrogênese e da fibroclasia espontânea na infecção pelo Trypanosoma cruzi. 2003. 98 f. Tese (Doutorado em Patologia) - Universidade Federal da Bahia; Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, 2003.
Date of defense: 2003
Place of defense: Salvador/BA
Department: Coordenação de Ensino
Defense institution: Universidade Federal da Bahia. Centro de Pesquisas Gonçalo Moniz
Program: Pós-Graduação em Patologia
Copyright: open access
Appears in Collections:BA - IGM - Teses de Doutorado

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