The motility, viability (percent live), 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. The
proportions of capacitated spermatozoa were increased by sorting, but were
lower when seminal plasma was present, rather than absent, from the staining
extender and the collection medium. Compared with unstained controls,
extension and staining without sorting only increased the proportion of
capacitated spermatozoa after washing in preparation for
in vitro fertilization. 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 for
control spermatozoa in the absence of seminal plasma, but in its presence
penetration and cleavage were substantially lower. The proportions of
capacitated spermatozoa were lower when seminal plasma was present in the
collection medium only than in the staining extender or when it was absent
altogether, but the former treatment substantially reduced the proportions of
polyspermic, penetrated and cleaved oocytes, and the proportion of
blastocysts. 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 this treatment reduces the ability of spermatozoa
to fertilize oocytes in vitro under these conditions.
Enhanced Binding of Zona Pellucida Proteins to the Acrosomal Region of Intact Boar Spermatozoa in Response to Fertilizing Conditions: A Flow Cytometric Study1
