ABSTRACT
The aim of the present study was to further evaluate the participation of D-mannose in the process of human sperm-egg interaction. Zona pellucida binding competitive assays in the presence of D-mannose were carried out using discarded oocytes from IVF. Spermatozoa were capacitated and D-mannose-binding site (MBS) expression, sperm viability and follicular fluidinduced acrosome reaction (AR) were evaluated. MBS were visualized using a fluorescein-neoglycoprotein probe. The capacity of free D-mannose and mannosylated albumin to induce the AR was also tested. MBS and the IVF outcome were also analysed. The involvement of D-mannose in sperm binding to the zona pellucida was verified by the inhibitory effect produced when the sugar was present during binding assays. MBS expression increased during capacitation, in parallel with the ability to undergo the induced AR. Mannosylated albumin, but not the free sugar, induced the AR. In acrosome-reacted spermatozoa, the MBS was located at the plasma membrane, as shown by confocal analysis. No significant difference in the increase in MBS expression was observed among the different IVF groups of patients. The data show that D-mannose is involved in the sperm-zona pellucida interaction, and that the expression of MBS on the sperm surface occurs during the acquisition of in-vitro sperm fertilizing ability.
Subject(s)
Mannose/metabolism , Sperm-Ovum Interactions/physiology , Spermatozoa/metabolism , Zona Pellucida/metabolism , Adult , Binding, Competitive , Female , Fertilization in Vitro , Humans , Male , Oocytes/metabolismABSTRACT
La infertilidad es un complejo fenòmeno donde diversos procesos biològicos, que se dan tanto en el hombre como en la mujer, asi como en la relaciòn entre ambos, deben interactuar de forma armònica entre sì para culminar en el logro de la concepciòn. En nuestro paìs la incidencia de infertilidad en la poblaciòn general es de un 12 y 15 por ciento. La realidad terapèutica es muy variada y diversa, y abarca una amplia gama de posibilidades que el especialista elige y aplica segùn cada caso particular. A veces se requieren tratamientos de menor o mayor complejidad, como las Tècnicas de Reproducciòn Asistida que tienen como finalidad incrementar las posibilidades del embarazo a travès de un acercamiento entre el ovocito y el espermatozoide, incluyendo la tècnica de inseminaciòn