Estudo do processo espermatogênico nos morcegos hematófagos Desmodus rotundus e Diphylla ecaudata (Chiroptera: Phyllostomidae)

Abstract

The vampire bats are the only mammals that feeds exclusively on the blood of mammals or birds. Due to this peculiarity, and your relationship with the transmission of the rabies viruses, they arouse great curiosities, being necessary the development of conservation managements that will enable the rational control of these species. To this end, it is essential that their reproductive cycles are known. Therefore, we aimed to describe the testicular activity of the species Desmodus rotundus and Diphylla ecaudata. After euthanasia procedures, its testicles were processed histologically for inclusion in historesin for morphological and morphometric analyses under light microscopy, Spurr’s resin for analysis of cellular ultrastructure under transmission microscopy electron, as well in histological paraffin for immunohistochemical analysis of expression of androgen receptors, aromatase, FGF2 and BCL-2. D. rotundus presented the percentage of seminiferous epithelium, number of Leydig cells per gram of testicle, and population of Sertoli cells and of A-type spermatogonia significantly higher in the rainy season, while the percentage of lumen, mitotic index, support capacity performed by Sertoli cell and spermatogenic yield were higher in the dry season. D. ecaudata presented gonadossomatic index of 0.49% and length of seminiferous tubules per gram of testis 32.20 m. Pre-meiotic, meiotic and post-meiotic phases accounted for, respectively, 56.20%, 9.30% and 34.50% of the seminiferous epithelium cycle of this species. Ultrastructure of spermatogenesis of both species were similar to that described in other mammals, and the perforatorium seems to be absent in their sperm. The immunohistochemical analysis revealed activity of the enzyme aromatase in Sertoli cells, Leydig cells, spermatocytes and spermatids, and the presence of androgen receptors in the cells of Sertoli and Leydig. FGF2 activity was more evident in the primary spermatocytes in zygotene and pachytene, as well in secondary spermatocytes and spermatids. On the other hand, the activity of the protein BCL-2 was more evident in the primary spermatocytes in pachytene and round spermatids. In D. rotundus, while the activity of aromatase, BCL-2 and androgen receptors were higher in the dry season, FGF2 activity was higher in the rainy season. It can be concluded that D. rotundus and D. ecaudata presented testicular pattern similar to that of other mammals, and characteristics that are common to those described in other bats species. The seasonal study of spermatogenesis in D. rotundus suggests a greater production of sperm in the rainy season at the Caatinga biome. This study is also the first step toward the knowledge of the reproduction of D. ecaudata, being this the first description about its spermatogenesis.