Browsing by Subject "Polyspermy"

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    Fertilization outcome could be regulated by binding of oviductal plasminogen to oocytes and by releasing of plasminogen activators during interplay between gametes
    (2012-02-02) Grullón, LA; Mondéjar Corbalán, Irene; García Vázquez, Francisco Alberto; Romar Andrés, Raquel; Coy Fuster, Pilar; Coy Fuster, Pilar; Fisiología; Facultades de la UMU
    Objective: To detect plasminogen and plasminogen activators (PA) in oviduct and oocytes and to clarify the role of the plasminogen/plasmin system on mammalian fertilization. Design: Experimental prospective study. Setting: Mammalian reproduction research laboratory. Animal(s): Oviducts and ovaries from porcine and bovine females were collected at slaughterhouse. A total of 52 oviducts and 2,292 oocytes were used. Boar and bull ejaculated spermatozoa were also used. Intervention(s): Plasminogen concentration in oviductal fluid (OF) through the cycle was measured. Immunolocalization of plasminogen and PAs in oocytes was carried out before and after fertilization. Porcine and bovine oocytes were in vitro fertilized, with plasminogen and plasmin added to the culture medium at different concentrations. Main Outcome Measure(s): Plasminogen concentration in OF. Plasminogen and PAs immunolocalization in oocytes. Penetration and monospermy rates, number of spermatozoa in the ooplasma and on the zona pellucida (ZP) after IVF. Result(s): Oviductal fluid contains about 92 mg/mL of plasminogen. The mature oocyte shows immunoreactivity toward plasminogen and toward PAs on its oolemma and ZP. After fertilization, plasminogen and PAs immunolabeling decreases in the oocyte, suggesting its conversion into plasmin. When exogenous plasminogen is added to the IVF medium, sperm entry into the oocyte is hampered, suggesting that the role of plasminogen activation during fertilization is to reduce the number of (or to select) penetrating spermatozoa. Conclusion(s): The plasminogen/plasmin system is activated during gamete interaction and regulates the sperm entry into the oocyte
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    How is plasminogen/plasmin system contributing to regulate sperm entry into the oocyte?
    (2013-12-30) Grullón LA; Gadea Mateos, Joaquín; Mondéjar Corbalán, Irene; Romar Andrés, Raquel; Matas Parra, Carmen; Coy Fuster, Pilar; Coy Fuster, Pilar; Fisiología; Facultades de la UMU
    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.