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Research article2011Peer reviewed

Cryopreservation-induced alterations in protein tyrosine phosphorylation of spermatozoa from different portions of the boar ejaculate

Kumaresan, A; Siqueira, AP; Hossain, MS; Bergqvist, Ann-Sofi


Previous studies have shown that boar sperm quality after cryopreservation differs depending on the ejaculate fraction used and that spermatozoa contained in the first 10 mL (P1) of the sperm-rich fraction (SRF) show better cryosurvival than those in the SRF-P1. Since protein tyrosine phosphorylation (PTP) in spermatozoa is related with the tolerance of spermatozoa to frozen storage and cryocapacitation, we assessed the dynamics of cryopreservation-induced PIP and intracellular calcium ([Ca(2+)]i) in spermatozoa, using flow cytometry, from P1 and SRF-P1 of the boar ejaculate at different stages of cryopreservation. Sperm kinetics, assessed using a computer-assisted semen analyzer, did not differ between PI and SRF-P1 during cryopreservation but the decrease in sperm velocity during cryopreservation was significant (P<0.05) in SRF-P1 compared to P1. There were no significant differences in percentages of spermatozoa with high [Ca(2+)]i between PI and SRF-P1 in fresh as well as in frozen-thawed semen. A higher (P<0.001) proportion of spermatozoa displayed PIP during the course of cryopreservation indicating a definite effect of the cryopreservation process on sperm PTP. The proportion of spermatozoa with PTP did not differ significantly between portions of the boar ejaculate. However at any given step during cryopreservation the percentage of spermatozoa with PTP was comparatively higher in SRF-P1 than P1. A 32 kDa tyrosine phosphorylated protein, associated with capacitation, appeared after cooling suggesting that cooling induces capacitation-like changes in boar spermatozoa. In conclusion, the study has shown that the cryopreservation process induced PTP in spermatozoa and their proportions were similar between portions of SRF. (C) 2011 Elsevier Inc. All rights reserved.


Boar spermatozoa; Ejaculate portions; Cryopreservation; Tyrosine phosphorylation; Flow cytometry

Published in

2011, Volume: 63, number: 3, pages: 137-144

    UKÄ Subject classification

    Animal and Dairy Science
    Veterinary Science

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