title: How is plasminogen/plasmin system contributing to regulate sperm entry into the oocyte?
abstract: Plasminogen is present in the oviduct, on the zona pellucida (ZP) and on oolemma, and reduces the number of sperm penetrating the oocyte during in vitro fertilization in pig and cow. It is unknown how this reduction occurs. We tested whether plasminogen (1) changed the ZP resistance to enzymatic digestion thus making the passage of the spermatozoa across it difficult; (2) reduced the sperm functionality, assessed by sperm viability, motility, spontaneous acrosome reaction and membrane lipid disorder; or (3) affected the sperm-ZP binding before or after sperm-ZP interaction. The mechanism by which plasminogen/plasmin system contributes to regulate sperm entry into the oocyte is not inducing a ZP hardening or a decrease in sperm functionality but detaching more than 50% of sperm bound to the ZP. It is suggested that the fertilizing spermatozoon activates plasminogen into plasmin at the oocyte surface and that plasmin removes additional spermatozoa attached to the ZP.
authors: Department of Physiology, Faculty of Veterinary, Regional Campus of International Excellence Campus Mare Nostrum, University of Murcia, Murcia, Spain.
authors: Luis A
authors: LA
authors: Grullón
authors: Joaquín
authors: J
authors: Gadea
authors: Irene
authors: I
authors: Mondéjar
authors: Carmen
authors: C
authors: Matás
authors: Raquel
authors: R
authors: Romar
authors: Pilar
authors: P
authors: Coy
mesh_terms: D020101:Acrosome Reaction; D000818:Animals; D002417:Cattle; D005260:Female; D005307:Fertilization in Vitro; D005341:Fibrinolysin / Q000378:metabolism*; D008297:Male; D008563:Membrane Lipids / Q000378:metabolism; D010958:Plasminogen / Q000378:metabolism*; D013081:Sperm Motility; D013084:Sperm-Ovum Interactions; D013094:Spermatozoa / Q000201:enzymology*; D013552:Swine; D013997:Time Factors; D015044:Zona Pellucida / Q000201:enzymology*
chemical_list: D008563:Membrane Lipids; D010958:Plasminogen; D005341:Fibrinolysin
keywords: IVF; plasmin; plasminogen; polyspermy; sperm-zona pellucida binding