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Inhibition of bovine sperm–oocyte fusion by the p ‐aminophenyl derivative of d ‐mannose
Author(s) -
Tanghe Sofie,
Van Soom A.,
Duchateau L.,
de Kruif A.
Publication year - 2004
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.10387
Subject(s) - human fertilization , oocyte , sperm , zona pellucida , andrology , biology , acrosome reaction , embryo , botany , anatomy , microbiology and biotechnology , medicine
Several steps in the process of mammalian fertilization are mediated by carbohydrates. This study investigated the role of the p ‐aminophenyl derivative of d ‐mannose (APMP) during bovine fertilization. Inseminating cumulus–oocyte complexes (COCs) in the presence of increasing APMP concentrations resulted in a significant dose‐dependent decrease of the fertilization rate ( P < 0.05). No negative effect of 50 mM APMP on total sperm motility and progressive motility was found. Subsequently, the fertilization steps at which this blocking effect could be exerted were investigated, i.e., sperm penetration of the cumulus oophorus, sperm‐zona binding, acrosome reaction, sperm–oolemma binding, and/or sperm–oocyte fusion. Inseminating cumulus‐enclosed and cumulus‐denuded oocytes in the presence of 50 mM APMP significantly decreased the fertilization rate to a comparable minimum level ( P < 0.05). There was no significant relationship between the number of spermatozoa bound to the zona pellucida and the APMP concentration, and APMP nor d ‐mannosylated bovine serum albumin (BSA) suppressed or stimulated sperm acrosomal status. Inseminating zona‐free oocytes in the presence of 50 mM APMP did not influence sperm–oolemma binding, but significantly inhibited sperm–oocyte fusion ( P < 0.05). Preincubating zona‐free oocytes with 200 μg/ml Con A but not with 50 mM APMP inhibited the sperm–oocyte fusion rate to the same extent as when the gametes were simultaneously exposed to 50 mM APMP. These data indicate that the blocking effect of APMP on bovine fertilization is mainly due to an inhibition of sperm–oocyte fusion, probably by specific obstruction of the sperm receptor sites that are responsible for the fusion process. Mol. Reprod. Dev. 67:224–232, 2004. © 2004 Wiley‐Liss, Inc.