Avaliação morfofuncional do testículo e do processo espermatogênico dos roedores silvestres Akodon cursor e Oligoryzomys nigripes (RODENTIA: Cricetidae)

• Autor(a) principal: Balarini, Maytê Koch
• Data de Publicação: 2013
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/266
• topic: Espermatogênese; Túbulo seminífero; Roedores silvestres; Imunohistoquímica; Célula de Leydig; Spermatogenesis; Seminiferous tubule; Wild rodents; Immunohistochemistry; Leydig cell; CNPQ::CIENCIAS BIOLOGICAS::BIOLOGIA GERAL

Rodents constitute the largest group of species diversity in the class Mammalia, individuals harboring a few grams such as the mouse, by species 90 kg as the capybara. Despite their diversity and high number of representatives, few is known about the reproductive biology of most animals of this group, which hinders the implementation of strategies for conservation and management of the same. For its diversity and the ease of being sampled systematically, wild rodents have become very useful models for research. Thus, the objective was to conduct studies of the spermatogenesis of Oligoryzomys nigripes and Akodon cursor, both endemic to the Atlantic Forest, in order to obtain basic data on the reproduction of wild rodents. Testicular fragments were processed for histological, immunohistochemical and ultrastructural. Gonadosomatic index found to O. nigripes and A. cursor was respectively 0.68% and 0.74%, while the index tubulossomatic was 0.58% and 0.66%. Each gram of testis of O. nigripes and A. cursor forward about 23 and 27 meters, respectively. In both species, the cycle of seminiferous epithelium were characterized in eight stages, according to the method of the tubular morphology and the cycle length was 3.93 days O. nigripes days and 4.26 A. cursor being required 17.68 and 19.15 days for the formation of spermatozoids from spermatogonia, respectively. The daily sperm production per gram of testis was 148x106 cells in O. nigripes and 142x106células in A. cursor. In O. nigripes and A. cursor, the pattern of organization of elements of the intertúbulo presented Leydig cells isolated or groupedgenerally associated with connective tissue and blood vessels and the seminiferous tubules separated by a lymphatic space. Although it is the most abundant element in the intertúbulo these species, the volume of individual Leydig cells was considered low, being 804.60 μm3 in O. nigripes and 858.7 μm3 in A. cursor. The number of these cells per gram of testis were, respectively, 25x106e 38x106 cells. The index leydigosomatic (ILG), was 0.026% in O. nigripes and 0.044% in A. cursor. It can be concluded that the species studied here showed a low percentage of intertubular tissue, and high volumetric percentage of seminiferous tubules in the testicular parenchyma, which together with the short duration of the seminiferous epithelium cycle, puts them among the species with daily sperm production record among mammals. Such characteristics may be closely related to the mating system of these species, indicating activity polyandrous or promiscuous.