title: The tubular compartment and the spermatogenic dynamics of the wild rodent Oxymycterus nasutus (Rodentia: Cricetidae).
abstract: Despite the order Rodentia present worldwide distribution and large number of species in the Brazilian fauna, detailed studies on testicular morphophysiology are still scarce. Therefore, this study aimed to analyze the dynamics of the spermatogenic process of Oxymycterus nasutus using morphometrical and stereological tools. Testicles from ten sexually mature males were used, showing a gonadosomatic index of 0.89%. The testicular parenchyma showed one of the highest tubulesomatic indexes reported among wild rodents - 0.82% - from which 65.12% was allocated into seminiferous epithelium. The average tubular diameter was 249.89 μm, whereas the epithelium height was 62.47 μm and the total length was 18.62 m per gram of testis. Eight different stages of the seminiferous epithelium cycle were described. Stage 1 was used for counting the germ cell population as well as the Sertoli cells. On average, 3.47 type-A spermatogonia, 24.39 primary spermatocytes in preleptotene/leptotene, 24.13 primary spermatocytes in pachytene, 68.38 round spermatids and 7.33 Sertoli cells were found per tubular cross section. There were 91.02 × 10(6) Sertoli cells per gram of testis and each cell was able to support 9.33 spermatids and 16.43 germ cells. The coefficient of spermatogonial mitosis was 7.02, while 2.83 spermatids were produced for each primary spermatocyte in pachytene. The overall efficiency of spermatogenesis was 19.70 cells, whereas the sperm reserve per gram of testis totalized 849.63 × 10(6) spermatids. Therefore, the presented data showed that O. nasutus shows a high energetic investment in reproduction, corroborating the findings for other species of the Cricetidae family.
authors.affiliation: Department of General Biology, Federal University of Viçosa (UFV) - Viçosa, Minas Gerais, 36570-000 Brazil.
authors.forename: Ana Carolina Torre
authors.initials: AC
authors.lastname: Morais
authors.affiliation: Department of General Biology, Federal University of Viçosa (UFV) - Viçosa, Minas Gerais, 36570-000 Brazil.
authors.forename: Maytê Koch
authors.initials: MK
authors.lastname: Balarini
authors.affiliation: Department of General Biology, Federal University of Viçosa (UFV) - Viçosa, Minas Gerais, 36570-000 Brazil.
authors.forename: Elizabeth Oliveira
authors.initials: EO
authors.lastname: Lopes
authors.affiliation: Department of General Biology, Federal University of Viçosa (UFV) - Viçosa, Minas Gerais, 36570-000 Brazil.
authors.forename: Tatiana Prata
authors.initials: TP
authors.lastname: Menezes
authors.affiliation: Department of Animal Biology, Federal University of Rio Grande do Sul (UFRGS) - Porto Alegre, Rio Grande do Sul, 91501-970 Brazil.
authors.forename: Fernando Marques
authors.initials: FM
authors.lastname: Quintela
authors.affiliation: Department of Morphology, Federal University of Rio Grande do Norte (UFRN) - Natal, Rio Grande do Norte, 59078-900 Brazil.
authors.forename: Danielle Barbosa
authors.initials: DB
authors.lastname: Morais
authors.affiliation: Department of General Biology, Federal University of Viçosa (UFV) - Viçosa, Minas Gerais, 36570-000 Brazil.
authors.forename: Marcos de Lucca M
authors.initials: Mde L
authors.lastname: Gomes
authors.affiliation: Department of General Biology, Federal University of Viçosa (UFV) - Viçosa, Minas Gerais, 36570-000 Brazil. Electronic address: smatta@ufv.br.
authors.forename: Sérgio Luis P da
authors.initials: SL
authors.lastname: Matta
mesh_terms: D000818:Animals; D003411:Arvicolinae / Q000502:physiology*; D008297:Male; D013091:Spermatogenesis / Q000502:physiology*; D013094:Spermatozoa / Q000502:physiology; D013737:Testis / Q000502:physiology*
keywords: Morphometry; Seminiferous epithelium; Sertoli cell; Spermiogenesis; Stereology; Testicle morphology