Infecção experimental de Calomys callosus (Rodentia Cricetidae) com Trypanosoma cruzi

Abstract

RESUMO: São apresentados resultados sobre a infecção experimental de Calomys callosus (Rodentia) e duas cepas (Y e Berenice) de Trypanosoma cruzi, isoladas de casos humanos. O estudo da evolução foi feito comparado com Mus musculus albino cepa "Swiss", quanto a prepatência, parasitemia, patência e letalidade. Análise histopatológica foi também conduzida em C. callosus, com o objetivo de verificar o tropismo tissular e agressividade das cepas neste roedor. Os experimentos mostraram que a evolução da infecção em C. Callosus foi diferente para as duas cepas de T. cruzi. A cepa Y apresentou maior parasitemia do que a cepa Berenice. O período prepatente variou com as doses utilizadas tendo sido mais curto nos animais inoculados com a cepa Y (2, 2-5, 2 dias) do que naquelas com a cepa Berenice (3, 2-7 dias). Embora as duas cepas inoculadas nos C. callosus tenham-se mostrado miotrópicas, as alterações tissulares foram mais acentuadas com a Y. Os resultados obtidos abrem perspectivas quanto à possibilidade do uso de C. callosus como animal experimental para T. cruzi.

Morphometry and acetylcholinesterase activity of the myenteric plexus of the wild mouse Calomys callosus

“…Mello (6) was the first to study the biology of the wild mouse Calomys callosus, and since then this animal species has been used in experiments with T. cruzi (2,7,8). In order to understand the changes occurring in the myenteric plexus in experimental Chagas' disease, information about their detailed structure in the normal state is required.…”

Participation of cytokines in the necrotic-inflammatory lesions in the heart and skeletal muscles of Calomys callosus infected with Trypanosoma cruzi

“…Adapted to laboratory studies (Mello 1982) this animal represents a very peculiar experimental model, with the capacity of to control the infection with virulent strains of T. cruzi as the Y strain (Mello 1979, Borges et al 1982. Interestingly, tissue lesions are precocious with intense inflammatory infiltrates and early fibrogenesis, with a spontaneous regression of inflammation and fibrosis (Andrade et al 1994, Lenzi et al 1995, Magalhães-Santos et al 2002, 2004.…”

Disruption of myofibrillar proteins in cardiac muscle of Calomys callosus chronically infected with Trypanosoma cruzi and treated with immunosuppressive agent

“…In this study, an experimental model of chronic Chagas' disease was used to gather information on myofibrillar distribution during the intracellular life cycle of T. cruzi in heart tissue, following reactivation of the disease by chemical immunosuppression. Previous studies with the wild rodent Calomys callosus used in our work, have indicated that the observed resistance toward natural or experimental T. cruzi infection (Borges et al 1982) may be overcome by cyclophosphamide-induced immunosuppression. C. callosus was thus employed as an alternative experimental model for reactivation of chronic chagasic infection.…”