Localisation of phospholipase Cζ1 (PLCZ1) and postacrosomal WW-binding protein (WBP2 N-terminal like) on equine spermatozoa and flow cytometry quantification of PLCZ1 and association with cleavage in vitro

2019 ◽  
Vol 31 (12) ◽  
pp. 1778
Author(s):  
Raul A. Gonzalez-Castro ◽  
Fabio Amoroso-Sanches ◽  
JoAnne E. Stokes ◽  
James K. Graham ◽  
Elaine M. Carnevale

Oocyte activation is initiated when a fertilising spermatozoon delivers sperm-borne oocyte-activating factor(s) into the oocyte cytoplasm. Candidates for oocyte activation include two proteins, phospholipase Cζ1 (PLCZ1) and postacrosomal WW-binding protein (PAWP; also known as WBP2 N-terminal like (WBP2NL)). We localised PLCZ1 and WBP2NL/PAWP in stallion spermatozoa and investigated the PLCZ1 content and sperm parameters as well as cleavage after intracytoplasmic sperm injection (ICSI). PLCZ1 was identified as 71-kDa protein in the acrosomal and postacrosomal regions, midpiece and principal piece of the tail. Anti-WBP2NL antibody identified two WBP2NL bands (~28 and ~32kDa) in the postacrosomal region, midpiece and principal piece of the tail. PLCZ1 and WBP2NL expression was positively correlated (P=0.04) in sperm heads. Flow cytometry evaluation of PLCZ1 revealed large variations in fluorescence intensity and the percentage of positively labelled spermatozoa among stallions. PLCZ1 expression was significantly higher in viable than non-viable spermatozoa, and DNA fragmentation was negatively correlated with PLCZ1 expression and the percentage of positively labelled spermatozoa (P<0.05). The use of equine sperm populations considered to have high versus low PLCZ1 content resulted in significantly higher cleavage rates after ICSI of bovine and equine oocytes, supporting the importance of PLCZ1 for oocyte activation.

Zygote ◽  
2003 ◽  
Vol 11 (1) ◽  
pp. 69-76 ◽  
Author(s):  
S.A. Ock ◽  
J.S. Bhak ◽  
S. Balasubramanian ◽  
H.J. Lee ◽  
S.Y. Choe ◽  
...  

In this study, the developmental capacity and cytogenetic composition of different oocyte activation protocols was evaluated following intracytoplasmic sperm injection (ICSI) of in vitro matured bovine oocytes. Motile spermatozoa selected by Percoll density gradient were treated with 5 mM dithiothreitol (DTT) and analysed for ultrastructural changes of the head using transmission electron microscopy (TEM). The alterations in sperm morphology after DTT treatment for different times (15, 30 and 60 min) were 10%, 45-55% and 70-85%, respectively. Further, a partial decondensation of sperm heads was observed after DTT treatment for 30 min. Oocytes were injected with sperm treated with DTT for 30 min. In group 1, sperm injection was performed without any activation stimulus to the oocytes. In group 2, sham injection without sperm was performed without activating the oocytes. Oocytes injected with sperm exposed to 5 μM ionomycin for 5 min (group 3), 5 μM ionomycin + 1.9 mM dimethylaminopurine (DMAP) for 3 h (group 4) and 5 µM ionomycin + 3 h culture in M199 + 1.9 mM DMAP (group 5) were also evaluated for cleavage, development and chromosomal abnormality. Cleavage and development rates in groups 1, 2 and 3 were significantly (p < 0.05) lower than those in groups 4 and 5. The incidence of chromosomal abnormality in the embryos treated directly with DMAP after ionomycin (group 4) was higher than in group 5. We conclude that immediate DMAP treatment after ionomycin exposure of oocytes results in arrest of release of the second polar body, and thus leads to changes in chromosomal pattern. Therefore, the time interval between ionomycin and DMAP plays a crucial role in bovine ICSI.


2018 ◽  
Vol 30 (1) ◽  
pp. 228
Author(s):  
R. A. Gonzalez-Castro ◽  
J. K. Graham ◽  
E. M. Carnevale

Fertilization failure in vivo and in vitro (intracytoplasmic sperm injection, ICSI) can be caused by the inability of sperm to elicit intracellular calcium oscillations and to induce oocyte activation. Phospholipase C zeta (PLCz) is sperm-associated protein that can induce oocyte activation. Male infertility has been associated with PLCz deficiency in various species, although this has not been studied in the stallion. We hypothesised that the location and amount of PLCz on sperm varies among stallions. The aim of this study was to validate commercial antibodies (Ab) to detect PLCz on stallion sperm, and then to use these Ab to quantify the amount of PLCz, using flow cytometry, with the long-term goal of correlating PLCz on sperm with stallion fertility. Frozen-thawed sperm were analysed (20 stallions in 3 replicates) using 2 commercial Ab (anti-mouse PLCz M163 and anti-human PLCz H50, Santa Cruz Biotechnology, TX, USA). Western blot and immunofluorescence microscopy were used to validate Ab binding. For microscopy, sperm DNA was counterstained with 1 µg mL−1 Hoechst 33258. For flow cytometry, samples were incubated with Live Dead Fixable Far Red Stain Kit (Molecular Probes, Eugene, OR, USA), fixed, permeabilized, incubated overnight with primary Ab, and labelled with conjugated secondary Ab (anti-rabbit IgG Alexa Fluor 488, Molecular Probes). Green and far red mean fluorescence intensity (MFI) were measured for 20,000 cells per sample. Results are presented as mean ± SEM. Wilcoxon test, Spearman rank correlation, and linear regression were performed for analyses. Immunoblot analyses for both commercial Ab identified an immunoreactive band of ~70 kDa in sperm heads, tails, and whole sperm; β-tubulin was used as loading control and for normalization. Microscopy revealed PLCz in the acrosomal and post-acrosomal regions, connecting piece, midpiece, and tail. Post-acrosomal localization was the pattern most frequently observed (55%), followed by acrosomal plus post-acrosomal regions (25%). The PLCz labelling was observed on >85% of midpiece and tail regions, independent of Ab used. Flow cytometric evaluation revealed that percentage of live sperm was 47 ± 2%. Similar fluorescence intensity was exhibited for both Ab (M163 and H50) with a wide range of values among stallions [M163, mean 30.7 ± 1.9 × 103 (range, 8.8-82.2 × 103); H50: 25.5 ± 3.2 × 103 (7.3-55.0 × 103)]. The percentage of live sperm within a sample was not associated with Ab MFI. However, when samples were gated for live/dead cells, live sperm exhibited higher (P < 0.001) MFI than dead sperm for M163 (42.6 ± 6.0 v. 30.6 ± 3.9 × 103) and H50 (38.4 ± 4.7 v. 25.6 ± 3.7 × 103). There was a strong and positive correlation between M163 and H50 MFI for total sperm and live sperm (total: r = 0.81, P < 0.001; live: r = 0.71; P < 0.001). In conclusion, 2 anti-PLCz commercial antibodies detected equine PLCz, and the PLCz was localised on the sperm as described. Flow cytometric evaluation showed that stallions have different quantities of PLCz on their sperm, and this may provide a mean to determine if PLCz on stallion sperm is associated with fertility.


2016 ◽  
Vol 44 (6) ◽  
pp. 1283-1291 ◽  
Author(s):  
Lin-Tao Xue ◽  
Rui-Xue Wang ◽  
Bing He ◽  
Wei-Ying Mo ◽  
Li Huang ◽  
...  

Objective To investigate the effect of sperm DNA fragmentation on the fertilization rate, embryo development and pregnancy outcome of in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) in a cohort of Chinese couples. Methods Infertile couples that had undergone assisted reproductive technology at our centre between January 2011 and December 2013 were included in this retrospective study. Fractions of prepared sperm samples were evaluated for sperm DNA fragmentation on the day of oocyte recovery. Results Of the 550 couples selected, 415 had undergone IVF and 135 ICSI. Sperm DNA fragmentation rate was significantly negatively correlated with the fertilization rate in the ICSI cycles but not the IVF cycles. No association was found between sperm DNA fragmentation and cleavage rate or good quality embryo formation rates in IVF or ICSI cycles. Receiver operating characteristic (ROC) curve analysis showed that the sperm DNA fragmentation rate was a statistically significant prognostic indicator of the clinical fertilization rate in ICSI cycles; a rate > 22.3% was associated with a lower fertilization rate following ICSI compared with a rate ≤ 22.3%. Conclusions High values of sperm DNA fragmentation were associated with a low fertilization rate following ICSI but were not associated with alterations in pregnancy or live birth rates in either ICSI or IVF in this cohort of Chinese couples.


PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6439 ◽  
Author(s):  
Wei Yin ◽  
Chun Wang ◽  
Kuohai Fan ◽  
Na Sun ◽  
Yaogui Sun ◽  
...  

Although the activation of pathogen phagocytosis via complement system has been studied, erythrocyte-phagocyte interactions in pigs are not clearly understood. Therefore, we sought to investigate the ability of porcine erythrocytes to clear immune complexes (ICs) by using laser confocal microscopy and flow cytometry to observe the immune adhesion of porcine erythrocytes to fluorescent bacilli and the immune presentation process of transferring fluorescent bacilli to macrophages. Isolated porcine alveolar macrophages (PAMs) had uniform morphology and size, and a survival rate of 97.2%. The phagocytosis rate was 98.8%. After WT E. coli was labeled with Fluorescein Isothiocyanate (FITC), the bacteria showed a bright green fluorescence, and the labeling rate was 92.3%. When laser confocal microscopy was utilized to observe the co-incubation system of porcine erythrocytes, PAM, and fluorescent E. coli, the fluorescence intensity of bacilli decreased with increasing observation time and even disappeared. Flow Cytometry examination showed that the average fluorescence intensity of PAMs co-incubated with porcine erythrocytes adhered to WT-E. coli-FITC, was significantly higher than that of normal PAMs. Furthermore, when porcine erythrocytes adhered to WT E. coli were incubated with PAMs, the surface mean fluorescence intensity of porcine erythrocytes was significantly higher than that of the blank control group. This shows that PAMs can competitively bind to the oposinized E. coli adhered to the surface of porcine erythrocytes, and these oposinized pathogens can enter macrophages by the process of phagocytosis, which promoting the internalization of ICs or pathogens. During this process, the physical morphology of porcine erythrocytes was not damaged, but the levels of its main functional protein CR1-like were reduced.


2008 ◽  
Vol 20 (1) ◽  
pp. 194
Author(s):  
C. B. Fernandes ◽  
L. G. Devito ◽  
L. R. Martins ◽  
T. S. Rascado ◽  
F. C. Landim-Alvarenga

In all mammalian species studied so far, fertilization induces oocyte activation necessary for pronuclear formation, syngamy, and the beginning of embryonic cleavage. The aim of this experiment was to evaluate the effectiveness of a protocol for artificial activation for bovine oocytes using ionomycin and roscovitine either in combination with intracytoplasmic sperm injection (ICSI) or alone. In this study, ionomycin was used to facilitate the increase of intracellular calcium, due to the release of calcium from intracellular stores. This compound was used in conjuction with roscovitine, a specific cdc2 kinase inhibitor. The success of the treatment was compared with that of oocytes fertilized by IVF. Three replicates were carried out using bovine oocytes harvested from slaughterhouse ovaries. In vitro-matured oocytes were cultured in TCM-199 plus 10% FCS, pyruvate, estradiol, hCG, and gentamicin at 39�C in an atmosphere of 5% of CO2 in air for 20 h. After in vitro maturation, oocytes were divided into 3 groups. For parthenogenetic activation, 100 oocytes were stripped of cumulus cells and placed in H-MEM plus 10% FCS and 5 µm ionomycin for 8 min, maintained in H-MEM plus 10% FCS, 66 mm roscovitine and 7.5 mg mL–1 cytochalasin B for 6 h, and placed into culture. In the ICSI group, oocytes were denuded and transferred to 5-µL H-MEM plus 20% FCS drops. Only MII oocytes were microinjected. The sperm drop was prepared with a mixture of 4 µL polyvinylpyrrolidone (PVP) and 1 µL of the sperm suspension produced by Percoll gradient. For injection, a single normal mobile sperm was aspirated with the tail first. A single oocyte was fixed by holding the pipette to position the polar body at the 6 or 12 o'clock position. The injection pipette was pushed through the zona pellucida and the oolema and the spermatozoan was released into the cytoplasm. After ICSI, the oocytes were subjected to the same activation protocol described earlier and cultured. For IVF, sperm was prepared by swim-up and 100 oocytes were fertilized in Fert-Talp for 18 h (sperm concentration: 1 � 106). All oocytes were cultured in HTF:BME plus 0.6% BSA, 10% FCS, 0.01% myoinositol, and gentamycin at 39�C in an atmosphere of 5% of CO2 in air for 72 h. Cleavage was evaluated visually and the embryos were stained with Hoechst 33342 for estimation of nuclei numbers. The data were analyzed by ANOVA, followed by the Tukey test (P < 0.05). The results showed a cleavage rate of 76% for the IVF group, 57% for the ICSI group, and 51% for the parthenogenic group. The artificial activation proposed was efficient in inducing oocyte activation and cleavage; however, the rates obtained were significantly lower then the ones observed after IVF. Injection of a viable sperm into the oocyte through ICSI did not improve the cleavage rate after activation. This result indicates that the membrane fusion and/or sperm interaction with the oocyte during fertilization is important for the physiological modifications that result in oocyte cleavage in bovine.


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