Submitted to: Journal Of Reproduction, Fertility And Development
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 20, 1999
Publication Date: N/A
Interpretive Summary: The membrane status of flow cytometrically sorted sperm is critical to the development of suitable procedures for preserving sexed sperm. Since seminal plasma is a natural component of semen it was deemed possible that it would be having some type of effect on the membrane of the sperm. This study was conducted with boar semen that was then sorted by the Beltsville Sperm Sexing Technology in the presence or absence of seminal plasma. Sorting itself increases the percentage of sperm that are capacitated. However, when sorted sperm were in the presence of seminal plasma, capacitated sperm were reduced. This effect carried over so that when the sorted sperm were used for in vitro fertilization they were less able to penetrate the egg. These studies enhance our understanding of the fertilization process and membrane status of the sperm and will be useful in developing preservation technology for flow cytometrically sorted boar sperm.
The motility, viability, capacitation status and in vitro fertility of boar spermatozoa were examined after staining with Hoechst 33342 and flow cytometric sorting in the absence or presence of seminal plasma. Viability was higher in unstained controls and when seminal plasma was present in the medium used to collect spermatozoa from the cell sorter than when seminal plasma was absent or in the staining extender only, but motility was highest when seminal plasma was included in the extender only compared with the controls and other treatments. Proportions of capacitated spermatozoa were increased by sorting, but were lower when seminal plasma was present than absent from the staining extender and the collection medium. Compared with unstained controls, extension and staining with sorting only increased the proportion of capacitated spermatozoa. The percentages of polyspermic, penetrated and cleaved oocytes were lower when inseminated with unsorted (stained) than control (unstained) spermatozoa, regardless of the presence or absence of seminal plasma. These parameters were higher for sorted than control spermatozoa in the absence of seminal plasma, but in its presence fertilization was substantially lower. These findings indicate that sperm capacitation associated with flow cytometric sorting can be reduced by the inclusion of seminal plasma in the collection medium but that this treatment reduced the ability of spermatozoa to fertilize oocytes in vitro.