Handling of boar spermatozoa during and after flow cytometric sex-sorting process to improve their in vitro fertilizing ability

The present study was conducted to reveal the effects of calcium and bicarbonate on the occurrence of head-to-head agglutination in ejaculated boar spermatozoa in vitro. Boar spermatozoa were washed and incubated in a modified Krebs-Ringer bicarbonate (mKRB) in a 37˚C CO2 incubator (5% CO2 in air) for 1–5 h. Before and after the incubation, aliquots of each sperm sample were fixed, smeared on glass slides, and stained with a phosphate-buffered solution of Giemsa to assess the percentages of head-to- head agglutinated spermatozoa. Before the incubation, only 5–12% of the spermatozoa were agglutinated. After the 1-h incubation, however, the percentage of head-to-head agglutinated spermatozoa rose to approximately 50%, followed by only minor increases thereafter. This rise was dependent on the concentrations of calcium chloride contained in the mKRB and was attenuated by the addition of 2 mM [ethylene-bis(oxyethylenenitrilo)]tetra-acetic acid (EGTA) to the medium. Moreover, the replacement of sodium bicarbonate with 2-[4-(2-hydroxyethyl)-1-piperazinyl]ethanesulfonic acid (Hepes) in the medium and treatment with ruthenium red, which have both been shown previously to inhibit calcium uptake by boar spermatozoa, significantly reduced the rise. Based on these findings, it was concluded that extracellular calcium and bicarbonate are key factors regulating head-to-head agglutination in boar spermatozoa. The possible relationship between agglutinability and the fertilizing ability of boar spermatozoa is also discussed.

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The capacitating agent bicarbonate induces protein kinase A-dependent changes in phospholipid transbilayer behavior in the sperm plasma membrane

Development ◽

10.1242/dev.127.11.2407 ◽

2000 ◽

Vol 127 (11) ◽

pp. 2407-2420 ◽

Cited By ~ 2

Author(s):

B.M. Gadella ◽

R.A. Harrison

Keyword(s):

Plasma Membrane ◽

Membrane Lipid ◽

Lipid Disorder ◽

Outer Leaflet ◽

Flow Cytometric ◽

Merocyanine 540 ◽

Sperm Plasma Membrane ◽

Dependent Protein ◽

Boar Spermatozoa

A flow cytometric procedure was used to follow the effect of bicarbonate, a key inducer of sperm capacitation in vitro, on the transbilayer behavior of C6NBD-phospholipids in the plasma membrane of living acrosome-intact boar spermatozoa under physiological conditions. In the absence of bicarbonate, 97% of C6NBD-phosphatidylserine and 78% of C6NBD-phosphatidylethanolamine was rapidly translocated from the outer leaflet to the inner, whereas relatively little C6NBD-phosphatidylcholine and C6NBD-sphingomyelin was translocated (15% and 5%, respectively). Inclusion of 15 mM bicarbonate/5%CO(2) markedly slowed down the rates of translocation of the aminophospholipids without altering their final distribution, whereas it increased the proportions of C6NBD-phosphatidylcholine and C6NBD-sphingomyelin translocated (30% and 20%, respectively). Bicarbonate activated very markedly the outward translocation of all four phospholipid classes. The changes in C6NBD-phospholipid behavior were accompanied by increased membrane lipid disorder as detected by merocyanine 540, and also by increased potential for phospholipase catabolism of the C6NBD-phospholipid probes. All three changes were mediated via a cAMP-dependent protein phosphorylation pathway. We suspect that the changes result from an activation of the non- specific bidirectional translocase ('scramblase'). They have important implications with respect to sperm fertilizing function.

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The relationship between membrane status and fertility of boar spermatozoa after flow cytometric sorting in the presence or absence of seminal plasma

Reproduction Fertility and Development ◽

10.1071/rd98102 ◽

1998 ◽

Vol 10 (5) ◽

pp. 433 ◽

Cited By ~ 75

Author(s):

W. M. C. Maxwell ◽

C. R. Long ◽

L. A. Johnson ◽

J. R. Dobrinsky ◽

G. R. Welch

Keyword(s):

Seminal Plasma ◽

Hoechst 33342 ◽

Cell Sorter ◽

Vitro Fertilization ◽

Flow Cytometric ◽

Collection Medium ◽

Flow Cytometric Sorting ◽

Boar Spermatozoa ◽

The Relationship

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.

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Proteomics-Based Characterization of the Effects of MMP14 on the Protein Content of Exosomes from Corneal Fibroblasts

Protein and Peptide Letters ◽

10.2174/0929866527666200408142827 ◽

2020 ◽

Vol 27 (10) ◽

pp. 979-988

Author(s):

Kyu-Yeon Han ◽

Jin-Hong Chang ◽

Dimitri T. Azar

Keyword(s):

Protein Content ◽

Catalytic Domain ◽

Protein Composition ◽

Proteomics Analysis ◽

Knock Out ◽

Corneal Fibroblast ◽

Flow Cytometric ◽

Corneal Fibroblasts ◽

Liquid Chromatography Tandem Mass

Background: Exosomes secreted by corneal fibroblasts contain matrix metalloproteinase (MMP) 14, which is known to influence pro-MMP2 accumulation on exosomes. Accordingly, we hypothesized that the enzymatic activity of MMP14 may alter the protein content of corneal fibroblast- secreted exosomes. Objective: The aim of this study was to investigate the effects of MMP14 on the composition and biological activity of corneal fibroblast-derived exosomes. Methods: Knock out of the catalytic domain (ΔExon4) of MMP14 in corneal fibroblasts was used to determine the effect of MMP14 expression on the characteristics of fibroblast-secreted exosomes. The amount of secreted proteins and their size distribution were measured using Nano Tracking Analysis. Proteins within exosomes from wild-type (WT) and ΔExon4-deficient fibroblasts were identified by liquid chromatography-tandem mass spectrometry (MS/MS) proteomics analysis. The proteolytic effects of MMP14 were evaluated in vitro via MS identification of eliminated proteins. The biological functions of MMP14-carrying exosomes were investigated via fusion to endothelial cells and flow cytometric assays. Results: Exosomes isolated from WT and ΔExon4-deficient fibroblasts exhibited similar size distributions and morphologies, although WT fibroblasts secreted a greater amount of exosomes. The protein content, however, was higher in ΔExon4-deficient fibroblast-derived exosomes than in WT fibroblast-derived exosomes. Proteomics analysis revealed that WT-derived exosomes included proteins that regulated cell migration, and ΔExon4 fibroblast-derived exosomes contained additional proteins that were cleaved by MMP14. Conclusion: Our findings suggest that MMP14 expression influences the protein composition of exosomes secreted by corneal fibroblasts, and through those biological components, MMP14 in corneal fibroblasts derived-exosomes may regulate corneal angiogenesis.

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