title: Factors influencing sperm-zona pellucida binding in vitro using the intact zona model.
abstract: The zona pellucida binding assay assesses the ability of spermatozoa to bind to the zona pellucida. The present study investigated the influence of: (i) prior oocyte exposure to spermatozoa on subsequent sperm-zona pellucida binding in vitro; and (ii) cryopreservation of oocytes. Only oocytes obtained from fertile donors were used and the binding capacity of non-inseminated, cryopreserved oocytes was compared with both inseminated/unfertilized, cryopreserved oocytes and inseminated/unfertilized, non-cryopreserved oocytes recovered from in-vitro fertilization cultures on sperm-zona pellucida binding using an intact zona model. There was no statistically significant difference in sperm-zona binding between non-inseminated, cryopreserved oocytes (range 9.6-23.2), inseminated/unfertilized, cryopreserved oocytes (range 15.0-16.0) and inseminated/ unfertilized, non-cryopreserved oocytes (range 3.3-23.0). The coefficient of variation for sperm binding to all oocyte groups was very large (range 37-121%). We conclude that neither prior exposure of human oocytes to human spermatozoa nor cryopreservation of human oocytes influences the subsequent binding of a different population of spermatozoa to the zona pellucida. However, large oocyte-to-oocyte variation of sperm-zona binding may diminish the usefulness of this assay in clinical practice and as a research tool.
authors.affiliation: Department of Obstetrics and Gynecology, University of Southern California School of Medicine, Los Angeles, USA.
authors.forename: J W
authors.initials: JW
authors.lastname: Graczykowski
authors.forename: M M
authors.initials: MM
authors.lastname: Francis
authors.forename: R J
authors.initials: RJ
authors.lastname: Paulson
authors.forename: R Z
authors.initials: RZ
authors.lastname: Sokol
mesh_terms: D015925:Cryopreservation; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D008297:Male; D009865:Oocytes / Q000502:physiology; D013084:Sperm-Ovum Interactions; D013094:Spermatozoa / Q000378:metabolism*; D015044:Zona Pellucida / Q000378:metabolism*