Spermatocyte apoptosis, which involves both intrinsic and extrinsic pathways, explains the sterility of Graomys griseoflavus × Graomys centralis male hybrids
Valeria Rodriguez A , Gabriela Diaz de Barboza A , Ruben Ponce B , Valeria Merico C , Silvia Garagna C D and Nori Tolosa de Talamoni A EA Laboratorio ‘Dr Cañas’, Bioquimica y Biologia Molecular, Facultad de Ciencias Medicas, Universidad Nacional de Cordoba, Cordoba, Argentina.
B Quimica y Fisica Biologicas, Facultad de Odontología, Universidad Nacional de Cordoba, Cordoba, Argentina.
C Dipartimento di Biologia Animale, Universitá degli Studi di Pavia, Pavia, Italy.
D Centro di Ricerca Interdipartimentale di Ingegneria Tissutale e Centro di Eccellenza in Biologia Applicata, Universitá degli Studi di Pavia, Pavia, Italy.
E Corresponding author. Email: ntolosa@biomed.uncor.edu
Reproduction, Fertility and Development 22(2) 478-488 https://doi.org/10.1071/RD09106
Submitted: 24 April 2009 Accepted: 3 September 2009 Published: 4 January 2010
Abstract
Spermatogenic impairment and the apoptotic pathways involved in establishing sterility of male hybrids obtained from crossing Graomys griseoflavus females with Graomys centralis males were studied. Testes from G. centralis, G. griseoflavus and hybrids were compared at different ages. Terminal transferase-mediated dUTP nick-end labelling assay (TUNEL), Fas, Bax and cytochrome c labelling were used for apoptosis evaluation, and calbindin D28k staining as an anti-apoptotic molecule. In 1-month-old animals, spermatocytes were positive for all apoptotic markers, but moderate TUNEL (+) spermatocyte frequency was only found in G. centralis. At subsequent ages, the apoptotic markers were downregulated in testes from parental cytotypes, but not in hybrid testes. TUNEL (+) spermatocytes were present at 78% and 44% per tubule cross-section in 2- and 3-month-old hybrid animals, respectively. Pachytene spermatocyte death in adult hybrids occurs via apoptosis, as revealed by high caspase-3 expression. Calbindin was highly expressed in spermatocytes of adult hybrids, in which massive cell death occurs via apoptosis. Calbindin co-localisation with TUNEL or Fas, Bax and cytochrome c was very limited, suggesting an inverse regulation of calbindin and apoptotic markers. Hybrid sterility is due to breakdown of spermatogenesis at the pachytene spermatocyte stage. Both extrinsic and intrinsic pathways are involved in apoptosis of spermatocytes, which are the most sensitive cell type to apoptotic stimuli.
Additional keywords: germ cells, mice, Robertsonian fusions.
Acknowledgements
This work was supported by a Bilateral Grant (2005–2007) from SECYT-MAE (Argentina-Italia), and funds from FONCYT (PICT2005–32464), CONICET (PIP 2005–2006) and SECYT (UNC) (Dr Nori Tolosa de Talamoni) and from FIRB 2005 (Project n. RBIP06FH7J), UNIPV-Regione Lombardia Project on Material Science and Biomedicine (Dr Silvia Garagna). Dr Nori Tolosa de Talamoni is a Member of Career from CONICET (Argentina). Valeria Rodriguez is a recipient of a fellowship from CONICET (Argentina). Special thanks are giving to Dr Gerardo Theiler and investigators from Laboratory ‘Dr F. Cañas’ (Argentina) for helping with the capture of G. centralis, Dr Ricardo Ojeda and Daniela Rodriguez for helping with the capture of G. griseoflavus and Dr Liliana Muñoz for testosterone determinations. The authors declare that there is no conflict of interest that would prejudice the impartiality of this scientific work.
Abercrombie, M. (1946). Estimation of nuclear population from microtome sections. Anat. Rec. 94, 239–247.
| Crossref | GoogleScholarGoogle Scholar |
O’Donnell, L. , McLachlan, R. I. , Wreford, N. G. , de Kretser, D. M. , and Robertson, D. M. (1996). Testosterone withdrawal promotes stage-specific detachment of round spermatids from the rat seminiferous epithelium. Biol. Reprod. 55, 895–901.
| Crossref | GoogleScholarGoogle Scholar | PubMed |
Redi, C. A. , Garagna, S. , Hilscher, B. , and Winking, H. (1985). The effects of some Robertsonian chromosome combinations on the seminiferous epithelium of the mouse. J. Embryol. Exp. Morphol. 85, 1–19.
| PubMed |
Riedl, S. J. , and Shi, Y. (2004). Molecular mechanisms of caspase regulation during apoptosis. Nat. Rev. Mol. Cell Biol. 5, 897–907.
| Crossref | GoogleScholarGoogle Scholar | PubMed |
Sánchez-Gómez, M. V. , Alberdi, E. , Ibarretxe, G. , Torre, I. , and Matute, C. (2003). Caspase-dependent and caspase-independent oligodendrocyte death mediated by AMPA and kainate receptors. J. Neurosci. 23, 9519–9528.
| PubMed |
Scaffidi, C. , Fulda, S. , Srinivasan, A. , Friesen, C. , Li, F. , Tomaselli, K. J. , Debatin, K. M. , Krammer, P. H. , and Peter, M. E. (1998). Two CD95 (APO-1/Fas) signalling pathways. EMBO J. 17, 1675–1687.
| Crossref | GoogleScholarGoogle Scholar | PubMed |
Show, M. D. , Folmer, J. S. , Anway, M. D. , and Zirkin, B. R. (2004). Testicular expression and distribution of the rat bcl2 modifying factor in response to reduced intratesticular testosterone. Biol. Reprod. 70, 1153–1161.
| Crossref | GoogleScholarGoogle Scholar | PubMed |
Sofikitis, N. , Ono, K. , Yamamoto, Y. , Papadopoulos, H. , and Miyagawa, I. (1999). Influence of the male reproductive tract on the reproductive potential of round spermatids abnormally released from the seminiferous epithelium. Hum. Reprod. 14, 1998–2006.
| Crossref | GoogleScholarGoogle Scholar | PubMed |
Sofikitis, N. , Giotitsas, N. , Tsounapi, P. , Baltoqiannis, D. , Giannakis, D. , and Pardalidis, N. (2008). Hormonal regulation of spermatogenesis and spermiogenesis. J. Steroid Biochem. Mol. Biol. 109, 323–330.
| Crossref | GoogleScholarGoogle Scholar | PubMed |
Theiler, G. R. , and Blanco, A. (1996). Patterns of evolution in Graomys griseoflavus (Rodentia, Muridae): II. Reproductive isolation between cytotypes. J. Mammal. 77, 776–784.
| Crossref | GoogleScholarGoogle Scholar |
Theiler, G. R. , Gardenal, C. N. , and Blanco, A. (1999a). Patterns of evolution in Graomys griseoflavus (Rodentia, Muridae). IV. A case of rapid speciation. J. Evol. Biol. 12, 970–979.
| Crossref | GoogleScholarGoogle Scholar |
Theiler, G. R. , Ponce, R. H. , Fretes, R. E. , and Blanco, A. (1999b). Reproductive barriers between the 2n=42 and 2n=36–38 cytotype of Graomys (Rodentia, Muridae). Mastozoologia Neotropical 6, 129–133.
Wallace, B. M. , Searle, J. B. , and Everett, C. A. (2002). The effect of multiple simple Robertsonian heterozygosity on chromosome pairing and fertility of wild-stock house mice (Mus musculus domesticus). Cytogenet. Genome Res. 96, 276–286.
| Crossref | GoogleScholarGoogle Scholar | PubMed |
Zambelli, A. , and Vidal-Rioja, L. (1999). Molecular events during chromosomal divergence of the South American rodent Graomys griseoflavus. Acta Theriol. 44, 345–352.
Zambelli, A. , Vidal-Rioja, L. , and Wainberg, R. (1994). Cytogenetic analysis of autosomal polymorphism in Graomys griseoflavus (Rodentia, Cricetidae). Z. Saugetierkd. 59, 14–20.
Zambelli, A. , Catanesi, C. I. , and Vidal-Rioja, L. (2003). Autosomal rearrangements in Graomys griseoflavus (Rodentia): a model of non-random Robertsonian divergence. Hereditas 139, 167–173.
| Crossref | GoogleScholarGoogle Scholar | PubMed |
