title: Comparative analysis of apoptotic pathways in rat, mouse, and hamster spermatozoa.
abstract: Apoptosis is a type of cell death characterized by the activation of a family of cysteine-proteases called caspases. We made a comparative study to determine the presence of several caspases and other regulators of apoptosis in rat, mouse, and hamster spermatozoa. Our results showed that the three species have both active and inactive caspases-8 and -3, the proapoptotic protein BID, p53, and the endogenous caspase inhibitor cIAP-1. However, we did not find evidence for the presence of active caspase-9. The acrosome reaction (i.e., the exocytic process of sperm acrosome) and sperm viability were not affected by the presence of a general caspase inhibitor. On the other hand, valinomycin, which promotes caspase-dependent cell death in somatic cells, induced caspase-independent cell death in spermatozoa. TRAIL, a ligand whose receptor induces apoptosis in malignant cells, did not have any effect in the viability of mouse spermatozoa, despise the presence of its receptor in rat and mouse, but not in hamster spermatozoa. Therefore, our results strongly suggest that rodent spermatozoa have some components of the apoptotic pathway. However, the role of caspases in mammalian spermatozoa appears to be unrelated to sperm survival or to the acrosome reaction under physiological conditions.
authors.affiliation: Departamento de Ciencias Fisiológicas, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile and Millennium Nucleus for Developmental Biology, Santiago, Chile.
authors.forename: Pablo
authors.initials: P
authors.lastname: Cisternas
authors.forename: Ricardo D
authors.initials: RD
authors.lastname: Moreno
mesh_terms: D020101:Acrosome Reaction; D000818:Animals; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism* / Q000494:pharmacology; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism*; D006224:Cricetinae; D051034:Inhibitor of Apoptosis Proteins / Q000378:metabolism; D008297:Male; D008562:Membrane Glycoproteins / Q000494:pharmacology; D051379:Mice; D051381:Rats; D013094:Spermatozoa / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D053221:TNF-Related Apoptosis-Inducing Ligand; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D014634:Valinomycin / Q000494:pharmacology
chemical_list: D051017:Apoptosis Regulatory Proteins; D061945:Caspase Inhibitors; D051034:Inhibitor of Apoptosis Proteins; D008562:Membrane Glycoproteins; D053221:TNF-Related Apoptosis-Inducing Ligand; C505654:Tnfsf10 protein, mouse; C505655:Tnfsf10 protein, rat; D014409:Tumor Necrosis Factor-alpha; D016159:Tumor Suppressor Protein p53; D014634:Valinomycin; D020169:Caspases