Citotaxonomia de Trypanosoma cruzi (Chagas, 1909) e influência desse agente etiológico nas células de Triatoma infestans (Klug, 1834)
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Data
2020-02-28
Autores
Oliveira, Ana Beatriz Bortolozo de
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Universidade Estadual Paulista (Unesp)
Resumo
O protozoário Trypanosoma cruzi é o agente etiológico da doença de Chagas, uma doença parasitária negligenciada e potencialmente fatal que apresenta grande importância para a saúde pública de diversos países. Atualmente, existem sete unidades discretas de tipagem (DTUs) de T. cruzi classificadas com base em diferentes marcadores moleculares, sendo TcI e TcII os mais importantes do ponto de vista epidemiológico. A transmissão desse protozoário ocorre principalmente por meio dos triatomíneos, no entanto, a relação entre o parasito e o vetor ainda é pouco explorada e alguns estudos relatam efeitos negativos causados pela infecção, o que ressalta a importância de aprofundar a compreensão dessa interação. Assim, objetivou-se: i) caracterizar citogeneticamente duas importantes cepas de T. cruzi, a saber, Bolívia e Y (representantes de TcI e TcII, respectivamente), a fim de estabelecer métodos mais acessíveis e efetivos para a identificação das DTUs e ii) aprofundar a compreensão sobre a interação parasito-vetor, por meio de análises citogenéticas e/ou estruturais de células de testículo (espermatogênese) e túbulos de Malpighi de Triatoma infestans infectado com a cepa Bolívia de T. cruzi. A análise citogenética das cepas de T. cruzi possibilitou diferenciar os grupos TcI e TcII, com base no grau de heteropicnose do núcleo. O estudo citogenético e estrutural dos insetos infectados permitiu observar que a espermatogênese de T. infestans ocorreu normalmente, sugerindo que as alterações inicialmente relatadas para os aspectos reprodutivos resultam da influência do protozoário sobre a gametogênese das fêmeas. Além disso, a caracterização citogenética das células dos túbulos de Malpighi de T. infestans demonstrou que a infecção também não altera a morfologia nuclear e o metabolismo celular, demonstrando que a presença do T. cruzi não acarreta em prejuízo para o órgão excretor. A diferenciação de TcI e TcII e o conhecimento da relação parasito-vetor mostraram-se importantes do ponto de vista entoepidemiológico. Ainda, a correta identificação das cepas, por meio da citogenética clássica, também pode auxiliar no diagnóstico clínico da doença de Chagas.
The protozoan Trypanosoma cruzi is the etiologic agent of Chagas disease, a neglected and potentially fatal parasitic disease that presents great importance for public health in several countries. There are currently seven discrete typing units (DTUs) of T. cruzi classified based on different molecular markers, being TcI and TcII the most important from the epidemiological point of view. The transmission of this protozoan occurs mainly through triatomines, however, the relationship between the parasite and the vector is still poorly explored and some studies report negative effects caused by the infection, which highlights the importance of deepening the understanding of this interaction. Thus, the objective was: i) characterize cytogenetically two important strains of T. cruzi, namely, Bolivia and Y (representatives of TcI and TcII, respectively), in order to establish more accessible and effective methods for the identification of DTUs and ii) deepen the understanding about the parasite-vector interaction, through cytogenetic and/or structural analysis of testis cells (spermatogenesis) and Malpighian tubules of Triatoma infestans infected with T. cruzi strain of Bolivia. Cytogenetic analysis of T. cruzi strains made it possible to differentiate the TcI and TcII groups, based on the pattern of heteropycnosis of the nucleus. The cytogenetic and structural study of the infected insects allowed to observe that the spermatogenesis of T. infestans occurred normally, suggesting that the alterations initially reported for the reproductive aspects result from the influence of the protozoan on the females gametogenesis. In addition, cytogenetic characterization of the Malpighian tubules cells of T. infestans demonstrated that the infection also does not change the nuclear morphology and cell metabolism, demonstrating that the presence of T. cruzi does not cause damage to the excretory organ. The differentiation of TcI and TcII and the knowledge of the parasitevector relationship proved to be important from the entoepidemiological point of view. Still, the correct identification of the strains, through classic cytogenetics, can also help in the clinical diagnosis of Chagas disease.
The protozoan Trypanosoma cruzi is the etiologic agent of Chagas disease, a neglected and potentially fatal parasitic disease that presents great importance for public health in several countries. There are currently seven discrete typing units (DTUs) of T. cruzi classified based on different molecular markers, being TcI and TcII the most important from the epidemiological point of view. The transmission of this protozoan occurs mainly through triatomines, however, the relationship between the parasite and the vector is still poorly explored and some studies report negative effects caused by the infection, which highlights the importance of deepening the understanding of this interaction. Thus, the objective was: i) characterize cytogenetically two important strains of T. cruzi, namely, Bolivia and Y (representatives of TcI and TcII, respectively), in order to establish more accessible and effective methods for the identification of DTUs and ii) deepen the understanding about the parasite-vector interaction, through cytogenetic and/or structural analysis of testis cells (spermatogenesis) and Malpighian tubules of Triatoma infestans infected with T. cruzi strain of Bolivia. Cytogenetic analysis of T. cruzi strains made it possible to differentiate the TcI and TcII groups, based on the pattern of heteropycnosis of the nucleus. The cytogenetic and structural study of the infected insects allowed to observe that the spermatogenesis of T. infestans occurred normally, suggesting that the alterations initially reported for the reproductive aspects result from the influence of the protozoan on the females gametogenesis. In addition, cytogenetic characterization of the Malpighian tubules cells of T. infestans demonstrated that the infection also does not change the nuclear morphology and cell metabolism, demonstrating that the presence of T. cruzi does not cause damage to the excretory organ. The differentiation of TcI and TcII and the knowledge of the parasitevector relationship proved to be important from the entoepidemiological point of view. Still, the correct identification of the strains, through classic cytogenetics, can also help in the clinical diagnosis of Chagas disease.
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Palavras-chave
Doença de Chagas, Citotaxonomia, TcI, TcII, Interação parasito-vetor, Chagas disease, Cytotaxonomy, Parasite-vector interaction