Influence of capacitation and fluids from the male and female genital tract on the zona binding ability of bull spermatozoa
Before fertilization, inseminated spermatozoa acquire the ability to fertilize an egg, a phenomenon called capacitation. Bovine sperm capacitation is influenced by factors originating from both the male and female genital tract, and results in intracellular and membrane changes of the spermatozoa th...
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Published in | Journal of reproduction & fertility Vol. 115; no. 1; pp. 175 - 183 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
England
Society for Reproduction and Fertility
01.01.1999
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Subjects | |
Online Access | Get full text |
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Summary: | Before fertilization, inseminated spermatozoa acquire the ability to fertilize an egg, a phenomenon called capacitation. Bovine
sperm capacitation is influenced by factors originating from both the male and female genital tract, and results in intracellular
and membrane changes of the spermatozoa that facilitate the induction of the acrosome reaction. However, the effects of reproductive
tract secretions and capacitation on the binding of spermatozoa to the zona pellucida have not been investigated. In this
study, a sperm–egg binding assay was used to determine whether the ability of bull spermatozoa to bind to the zona pellucida
was altered during in vitro capacitation by heparin or oviductal fluid, or by treatment of spermatozoa from the cauda epididymidis with accessory sex
gland fluid. In addition, biotinylated solubilized zona pellucida proteins were used to visualize zona binding on spermatozoa.
The ability of bull spermatozoa to bind to the zona pellucida was increased after both heparin and oviductal fluid induced
in vitro capacitation. Exposure of spermatozoa from the cauda epididymidis to accessory sex gland fluid resulted in a direct increase
in zona binding ability, followed by a further increase during capacitation in vitro . Binding of solubilized zona proteins was restricted to the acrosomal cap of bull spermatozoa. It is suggested that the observed
increased ability of bull spermatozoa to bind to the zona pellucida enables optimal sperm–egg attachment, which also relates
to the induction of the acrosome reaction by the zona pellucida. Thus, increased zona binding ability is likely to be an essential
part of the process of capacitation. |
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ISSN: | 1470-1626 0022-4251 1741-7899 |
DOI: | 10.1530/jrf.0.1150175 |