Spermatozoa in the sperm-peak-fraction of the boar ejaculate show a lower flow of Ca(2+) under capacitation conditions post-thaw which might account for their higher membrane stability after cryopreservation
2011 (English)In: Animal Reproduction Science, ISSN 0378-4320, E-ISSN 1873-2232, Vol. 128, no 1-4, 37-44 p.Article in journal (Refereed) Published
Boar spermatozoa collected in the ejaculate sperm peak-portion (P1, first 10 mL of the sperm-rich fraction, SRF), had shown a higher resilience to freezing and thawing compared to spermatozoa from the rest of the ejaculate (2nd portion of the SRF plus the post-sperm-rich fraction, PSRF), even when using a simplified freezing technique, as long as spermatozoa were incubated in their own seminal plasma (SP). This experiment studied the stability of P1- and SRF-P1 boar spermatozoa frozen in MiniFlatPacks (MFP), post-thaw, using flow cytometry. Since spermatozoa from either portion showed similar cryosurvival and low proportions of unstable membranes (less than3%, annexin-V/propidium iodide staining), and only a tendency for SRF-P1 live spermatozoa to depict acrosome exocytosis (FITC-PNA/PI/H33342); they were explored for Ca(2+) contents using a Fluo-4 probe under in vitro capacitating conditions (mBO+ medium), as well they were tested for their ability to sustain a short Ca(2+)-ionophore (A23187) in vitro challenge. The proportions of live spermatozoa depicting high Ca(2+)-levels were initially less than2% but increased over incubation time, particularly in SRF-P1(P less than 0.05), while proportions of live spermatozoa with low Ca(2+)-levels were basically constant over incubation time (similar to 11-14%), for either portion. Incubation in capacitation medium did not modify the proportions of low-Ca(2+) but dramatically increased the proportions of high-Ca(2+) spermatozoa (P less than 0.001) already after 15 min exposure, highest for SRF-P1 spermatozoa. While the proportion of live spermatozoa with intact acrosome was significantly decreased among SRF-P1 (P less than 0.001), that of P1-spermatozoa remained unchanged, probably owing to the lowest relative content of cytosolic Ca(2+). The results suggest that spermatozoa in the P1-portion are more resilient to express acrosome exocytosis post-thaw compared to those bathing in the rest of the SRF-fraction when cryopreserved using a simplified technique, in MFPs.
Place, publisher, year, edition, pages
Elsevier Masson , 2011. Vol. 128, no 1-4, 37-44 p.
Boar; Calcium; Membrane stability; Sperm; SRF
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:liu:diva-73348DOI: 10.1016/j.anireprosci.2011.08.006ISI: 000297892800005OAI: oai:DiVA.org:liu-73348DiVA: diva2:471362