Vitellogenesis and follicular regression in Dipetalogaster maxima, a vector of Chagas' disease

AGUIRRE, SA; FREDE,S; PONS, P; RUBIOLO, ER; CANAVOSO, LE

BIOCELL

Inca Editorial

Lugar: Mendoza, Argentina; Año: 2008 vol. 32 p. 82 - 82

0327-9545

In insects, reproduction entails an accurate compromise between factors promoting vitellogenesis and those causing follicular regression. In Chagas´ disease vectors, these aspects have been poorly investigated. In this work, we have analyzed the vitellogenic phase of D. maxima as well as morphological and cellular changes occurring in ovarian tissue during follicular regression. For the study, we have used western-blot, ELISA and immunohistochemical techniques. In addition, electron and fluorescence microscopy were employed to assess cellular changes. Results showed that: [a] vitellogenin protein expression in fat body and the levels in hemolymph were maximal between days 4-20 post-feeding; [b] during the vitellogenic phase, ovarian tissue showed a typical asynchronous development and some differential deposition of the protein according to the size of the follicles; [c] ovarioles entering in regression (from day 15 post-vitellogenesis) were poorly developed, and follicles presented nurse cells with different degree of vacuolization. In degenerating follicles, death of follicular cells occurred by apoptosis and necrosis. We conclude that in this vector, follicular atresia is complex. It can serve to promote resorption of some oocytes in order to sustain the development of younger follicles during the second vitellogenic cycle.