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Browsing Artículos by browse.metadata.advisor "Coy Fuster, Pilar"

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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.
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    Identification of potential oviductal factors responsible for zona pellucida hardening and monospermy during fertilization in mammals
    (2013-09-01) martinez martinez, Irene; Mondéjar Corbalán, Irene; Avilés Sánchez, Manuel; Coy Fuster, Pilar; Coy Fuster, Pilar; Fisiología
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    Supplementation of bovine follicular fluid during in vitro maturation increases oocyte cumulus expansion, blastocyst developmental kinetics and blastocyst cell number.
    (2019-01-14) Lopes, Jordana S; Canha-Gouveia, Analuce; París-Oller, Evelynne; Coy Fuster, Pilar; Coy Fuster, Pilar; Fisiología
    Bovine follicular fluid (bFF) is the natural milieu for oocyte growth and development. However, its value as supplementation to in vitro maturation medium is still questioned due to inconsistent results. In this study we hypothesized that adding 10% of follicular fluid as well as heat treating it to inhibit the complement system, would produce higher quality embryos. To do so, experiments were conducted to compare the effect of bFF and heat-treated bFF (bFFin) on oocyte competence assessed by different parameters such as nuclear and cytoplasmic maturation, IVF efficiency, in vitro embryo development and embryo survivability post-vitrification. No differences on nuclear maturation nor cortical granules migration were observed but differences were found on oocyte’s cumulus cell expansion, with bFF group having the highest increase (79.0±3.7%). bFFin had a negative impact on IVF efficiency (58.6±3.2%), but no differences were found between bFF (62.9±3.2%) and control (72.8±3.0%). Although the cleavage and blastocyst rate were similar between groups, the day 6 embryo development rate was higher in bFFin group, suggesting an accelerated developmental kinetics. Hatched blastocysts from the bFF group showed a higher cell count than the control group (241.3±20.1 and 185.8± 10.0, respectively), and bFFin embryos showed values in between (214.9±14.0). No difference on survivability post-vitrification was found between groups, although the blastocyst stage had a significant impact on the survival rate across all groups. In conclusion, using bFF as supplementation to maturation medium showed a higher benefit when comparing to the standard supplementation by having oocytes with higher cumulus expansion rate, faster development of embryos and higher number of cells per embryo. Inactivation of bFF lowered IVF efficiency but didn’t compromise blastocyst development and quality.
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    The human is an exception to the evolutionarily-conserved phenomenon of pre-fertilization zona pellucida resistance to proteolysis induced by oviductal fluid
    (2014-01-04) Mondéjar Corbalán, Irene; Avilés Sánchez, Manuel; Coy Fuster, Pilar; Coy Fuster, Pilar; Fisiología
    study question: Is zona pellucida (ZP) resistance to proteolysis, induced by oviductal fluid (OF), a mechanism common to species other than the pig and cow? summary answer: ZP resistance to proteolysis induced by OF was observed in the mouse, rat, hamster, rabbit, sheep, goat, pig and cow, but not in humans. what is known already: Oviductal ZP resistance to proteolysis occurs in the pig and cow where it influences the incidence of fertilization and polyspermy. The effect is observed after incubation of ZP in OFs from pig (pOF), cow (cOF), rabbit (rOF) and sheep (sOF). study design, size, duration: Oocytes from nine different species, including ungulates, rodents, lagomorphs and primates were incubated in rOF, sOF, gOF, cOF, pOF and human oviductal fluid (hOF). ZP digestion times for the matured oocytes of these nine species, without any treatment or incubated in 5 (mouse, rat, hamster, rabbit, cow, ewe and goat) or 6 (pig and humans) of the OFs collected were compared using three replicates per treatment and at least three oocytes per replicate. materials, setting, methods: In vivo matured oocytes from rat, hamster, mouse, rabbit and humans, in vitro matured oocytes from cow, goat, ewe and pig and rOF, cOF, gOF, sOF, pOF and human (hOF) were collected and processed for the study. Oocytes from each species were incubated in the different OFs for 30 min. The resistance of the ZP of the oocytes to enzymatic digestion in a pronase solution (0.5% in PBS) was measured and registered as ZP digestion time. main results and the role of chance: rOF increased ZP resistance to proteolytic digestion in the range of between 96 and 720 h for any of the species tested, whereas the corresponding increase in human ZP was only 1 min. OFs from the remaining species also had a significant effect, with variations among the cross-species experiments (P , 0.05). hOF, which was only tested on human and porcine oocytes, had no effect on ZP chemical hardening. Measurements of ZP digestion times are not of extreme accuracy and errors of a few seconds can be assumed in the experimental data. However, when differences are in the range of hours among treatments, variations measured in seconds do not alter the robustness of the findings. limitations, reasons for caution: Human oocytes and OF were of limited access, compared with oocytes from species collected in slaughterhouses. OFs from mouse, rat and hamster were not tested due to the small size of the genital tract in these species and the small volume of fluid available. wider implications of the findings: Since oviductal modification of ZP resistance to proteolytic digestion has been demonstrated to influence fertilization and this pre-fertilization mechanism is considered to contribute to the control of polyspermy, the apparent absence of this mechanism in humans suggests that the regulation of polyspermy depends mainly on other mechanisms, most probably of cortical granule origin. Investigation into a possible relationship between the lack of oviductal ZP hardening in human oocytes and the existence of tubal ectopic pregnancies in this species is proposed.