Cryopreservation affects bovine sperm intracellular parameters associated with capacitation and acrosome exocytosis.
Although semen cryopreservation is widely and commonly used in the bovine breeding industry, half the spermatozoa do not survive and most of those that do survive undergo numerous physiological changes that affect their fertilising ability. The aim of the present study was to determine how cryopreservation affects the intracellular events involved in sperm capacitation and acrosome reaction. Immediately after thawing and washing, almost 50% of spermatozoa were capacitated and more than 20% had lost their acrosome. The sperm cAMP concentration was lower than that in freshly ejaculated spermatozoa, but the cytosolic pH (pHcyt) was in the expected range. The free cytosolic Ca2+ concentration ([Ca2+]cyt) was higher than in fresh spermatozoa and cryopreserved spermatozoa had internally stored Ca2+. Phenylarsine oxide increased pHcyt and both cytosolic and stored Ca2+ concentrations, whereas orthovanadate enhanced acrosome loss and protein tyrosine phosphorylation (P-Tyr). Heparin increased the percentage of spermatozoa expressing the B (capacitated) chlortetracycline binding pattern, pHcyt, P-Tyr and Ca2+ storage. Moreover, positive correlations exist between capacitation, cAMP, P-Tyr and stored Ca2+, whereas the acrosome reaction is positively correlated with pHcyt and [Ca2+]cyt. These results demonstrate that sperm regulatory mechanisms may be affected by the cryopreservation procedure, but frozen-thawed sperm can still regulate their capacitation and acrosome reaction signalling pathways.
Pons-Rejraji
Hanae
H
Département d'Obstétrique-Gynécologie, Centre de Recherche en Biologie de la Reproduction, Université Laval, Quebec, QC G1V 4G2, Canada.
Bailey
Janice L
JL
Leclerc
Pierre
P
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D020101:Acrosome Reaction / Q000187:drug effects; D000818:Animals; D001152:Arsenicals / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002417:Cattle; D002470:Cell Survival; D002751:Chlortetracycline / Q000378:metabolism; D015925:Cryopreservation / Q000662:veterinary*; D000242:Cyclic AMP / Q000378:metabolism; D005089:Exocytosis / Q000187:drug effects; D006493:Heparin / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D008297:Male; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D019000:Phosphotyrosine / Q000378:metabolism; D017027:Protein Tyrosine Phosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism; D012099:Reproductive Techniques / Q000662:veterinary; D012662:Semen Preservation / Q000009:adverse effects* / Q000662:veterinary*; D015398:Signal Transduction; D013075:Sperm Capacitation / Q000187:drug effects; D013081:Sperm Motility; D013094:Spermatozoa / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D013997:Time Factors; D014638:Vanadates / Q000494:pharmacology
D001152:Arsenicals; D010726:Phosphodiesterase Inhibitors; C029341:oxophenylarsine; D019000:Phosphotyrosine; D014638:Vanadates; D006493:Heparin; D006861:Hydrogen Peroxide; D000242:Cyclic AMP; D017027:Protein Tyrosine Phosphatases; D002118:Calcium; D015056:1-Methyl-3-isobutylxanthine; D002751:Chlortetracycline