Cell death during follicular atresia in Dipetalogaster maxima (Hemiptera: Reduviidae), a vector of Chagas’ disease.

AGUIRRE, S.A.; PONS, P; SETTEMBRINI, B.P.; RUBIOLO, E.R.; CANAVOSO, L.E.

Foz do Iguaçu.

Otro; XLI Reunião Anual da Sociedade Brasileira de Bioquímica e Biologia Molecular.; 2012

Sociedade Brasileira de Bioquímica e Biologia Molecular

In insects, unfavorable physiological, environmental or nutritional conditions promote changes in the ovarian tissue, which in turn elicit the atresia of some terminal follicles and the final oocyte resorption. Although recent studies in some species indicate that during atresia, the follicular and/or nurse cells can be eliminated by programmed cell death mechanisms, these events were scarcely explored in Triatominae. The aim of this work was to investigate the cell death mechanisms operating during follicular atresia induced by nutritional deprivation in Dipetalogaster maxima, a vector of Chagas’ disease. For the study we performed light, fluorescence and electron microscopy, TUNEL assays, western blot and immunofluorescence. The results showed that in D. maxima, morphological changes during follicular atresia were established gradually. At early atresia follicular cells showed the presence of activated caspase-3 proteases and exhibited apoptotic nuclei characterized by chromatin condensation and DNA fragmentation. When food deprivation was stressed, cellular changes were more pronounced, and cytoplasm vacuolization and abundant autophagic vacuoles were clearly observed. This stage, termed late follicular atresia, was characterized by an intense fluorescence pattern of LC3-II, a marker for autophagy. Features compatible with necrosis were also observed at late stages of the atresia. The findings provide a better understanding of unexplored aspects of the biology of reproduction of Chagas disease vectors, which have a clear impact in the life cycle of the females.