title: Capacitation-like changes in equine spermatozoa throughout the cryopreservation process.
abstract: Chlortetracycline (CTC) fluorescence staining analysis was used to investigate cryopreservation-induced capacitation-like changes in equine spermatozoa. Freshly ejaculated spermatozoa were found to display a high proportion of F pattern cells (uncapacitated; 93.6%) and a lower proportion of B pattern (capacitated; 5.4%) and AR pattern (acrosome-reacted; 1%) cells. Following cryopreservation in modified Kenney's medium, capacitation-like changes were observed. There was a significant increase in the proportion of spermatozoa displaying the B pattern (64.8%; P<0.001) and AR pattern (32.8%; P<0.001), with a corresponding decrease in the proportion of spermatozoa displaying the F staining pattern (2.5%; P<0.001). Further analysis of CTC fluorescence staining patterns showed that there was a major decrease in the proportion of F pattern spermatozoa corresponding to an increase in B pattern spermatozoa following removal of seminal plasma after centrifugation and resuspension in freezing medium. There was a further decline in the proportion of F pattern spermatozoa, corresponding to increases in B and AR pattern spermatozoa, after the freezing and thawing steps. Resuspension of centrifuged spermatozoa in homologous seminal plasma did not induce capacitation-like changes. These data indicate that the process of freezing and thawing stallion semen induces capacitation-like changes in spermatozoa and that most of the change is brought about by removal of seminal plasma, with further changes induced by the actual freezing and thawing step.
authors.affiliation: Faculty of Veterinary Science, The University of Sydney, New South Wales, Australia.
authors.forename: M A
authors.initials: MA
authors.lastname: Schembri
authors.forename: D A
authors.initials: DA
authors.lastname: Major
authors.forename: J J
authors.initials: JJ
authors.lastname: Suttie
authors.forename: W M C
authors.initials: WM
authors.lastname: Maxwell
authors.forename: G
authors.initials: G
authors.lastname: Evans
mesh_terms: D020101:Acrosome Reaction; D000818:Animals; D002751:Chlortetracycline; D015925:Cryopreservation; D006736:Horses; D006358:Hot Temperature; D008297:Male; D008856:Microscopy, Fluorescence; D012662:Semen Preservation / Q000662:veterinary*; D013075:Sperm Capacitation; D013081:Sperm Motility
chemical_list: D002751:Chlortetracycline