title: Germ cell differentiation and proliferation in the developing testis of the South American plains viscacha, Lagostomus maximus (Mammalia, Rodentia).
abstract: Cell proliferation and cell death are essential processes in the physiology of the developing testis that strongly influence the normal adult spermatogenesis. We analysed in this study the morphometry, the expression of the proliferation cell nuclear antigen (PCNA), cell pluripotency marker OCT-4, germ cell marker VASA and apoptosis in the developing testes of Lagostomus maximus, a rodent in which female germ line develops through abolished apoptosis and unrestricted proliferation. Morphometry revealed an increment in the size of the seminiferous cords with increasing developmental age, arising from a significant increase of PCNA-positive germ cells and a stable proportion of PCNA-positive Sertoli cells. VASA showed a widespread cytoplasmic distribution in a great proportion of proliferating gonocytes that increased significantly at late development. In the somatic compartment, Leydig cells increased at mid-development, whereas peritubular cells showed a stable rate of proliferation. In contrast to other mammals, OCT-4 positive gonocytes increased throughout development reaching 90% of germ cells in late-developing testis, associated with a conspicuous increase in circulating FSH from mid- to late-gestation. TUNEL analysis was remarkable negative, and only a few positive cells were detected in the somatic compartment. These results show that the South American plains viscacha displays a distinctive pattern of testis development characterized by a sustained proliferation of germ cells throughout development, with no signs of apoptosis cell demise, in a peculiar endocrine in utero ambiance that seems to promote the increase of spermatogonial number as a primary direct effect of FSH.
authors.affiliation: Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y Diagnóstico, CEBBAD, Universidad Maimónides, Hidalgo 775, C1405BCK-Buenos Aires, Argentina.
authors.forename: C R
authors.initials: CR
authors.lastname: Gonzalez
authors.forename: M L
authors.initials: ML
authors.lastname: Muscarsel Isla
authors.forename: N A
authors.initials: NA
authors.lastname: Fraunhoffer
authors.forename: N P
authors.initials: NP
authors.lastname: Leopardo
authors.forename: A D
authors.initials: AD
authors.lastname: Vitullo
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D049109:Cell Proliferation; D005854:Germ Cells / Q000166:cytology* / Q000378:metabolism; D020287:In Situ Nick-End Labeling; D007985:Leydig Cells / Q000166:cytology / Q000378:metabolism; D008297:Male; D050814:Octamer Transcription Factor-3 / Q000378:metabolism; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D012377:Rodentia / Q000196:embryology* / Q000378:metabolism; D012708:Sertoli Cells / Q000166:cytology / Q000378:metabolism; D013737:Testis / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism
chemical_list: D050814:Octamer Transcription Factor-3; D018809:Proliferating Cell Nuclear Antigen