Affiliation:
1. Laboratory of Animal Reproduction, Faculty of Veterinary Medicine Universidad Nacional Mayor de San Marcos (UNMSM) Lima Peru
2. Faculty of Veterinary Sciences and Zootechnics Universidad Nacional Micaela Bastidas de Apurímac Abancay Peru
3. Universidad Científica del Sur (UCSUR) Lima Peru
4. Clinical Sciences Swedish University of Agricultural Sciences Uppsala Sweden
Abstract
AbstractCaspases are crucial mediators of programmed cell death (apoptosis). Apoptosis can occur in spermatozoa during spermatogenesis or epididymal transit, as well as in ejaculated spermatozoa. A high proportion of apoptotic sperm would be a poor indicator of the freezability of a raw seminal sample. Alpaca spermatozoa are notoriously difficult to freeze successfully. Therefore, the objectives of this study were to study caspase activation during incubation (37°C) of fresh alpaca spermatozoa, as well as before and after cryopreservation, to gain some insight into the mechanisms behind the vulnerability of alpaca spermatozoa. Eleven sperm samples were incubated for 4 h at 37°C (Study 1), and 23 samples were frozen using an automated system (Study 2). Caspase‐3/7 activation was assessed at 0,1,2,3, and 4 h in samples incubated at 37°C (Study 1); and before/after cryopreservation (Study 2) using CellEvent™ Caspase 3/7 Green Detection Reagent and flow cytometry. The proportions of alpaca spermatozoa with caspase‐3/7 activated increased (p < 0.05) after 3–4 h of incubation at 37°C; however, caspase activation was similar before and after cryopreservation (36.2 ± 11.2% vs. 36.6 ± 33.7%, p > 0.05). The high standard deviation found after freezing could be explained by the existence of two subpopulations: one subpopulation where caspase‐3/7 activation decreased during cryopreservation (from 36.6 ± 9.1% to 1.5 ± 2.2%), and the other subpopulation where caspase‐3/7 activation increased after cryopreservation (from 37.7 ± 13.0% to 64.3 ± 16.7%). In conclusion, after 3–4 h of incubation, caspase‐3/7 activation increased in fresh alpaca sperm, whereas cryopreservation affects alpaca sperm samples in different ways.
Funder
Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica
Universidad Nacional Mayor de San Marcos
Subject
Endocrinology,Animal Science and Zoology,Biotechnology