Relationship between sperm apoptosis and bull fertility: in vivo and in vitro studies

2016 ◽  
Vol 28 (9) ◽  
pp. 1369 ◽  
Author(s):  
Lauren Erickson ◽  
Tom Kroetsch ◽  
Muhammad Anzar

The objectives of this study were to confirm the relationship of apoptosis-associated membrane and nuclear changes in bull spermatozoa with field fertility, to predict the fertility of beef bulls used for natural breeding and to study the role of DNA-nicked spermatozoa in early embryonic development. In Experiment 1, the relationship between fertility and different sperm populations identified by the Annexin V/propidium iodide (PI) and terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) assays was determined. Bull fertility was related to live (P < 0.05) and necrotic (P < 0.01) and DNA-nicked (P < 0.001) spermatozoa. In Experiment 2, the percentage of DNA-nicked spermatozoa was determined in 15 beef bulls used for natural breeding and their fertility potential was determined using a regression model developed in Experiment 1.The predicted fertility deviation of beef bulls ranged from –7.3 to 2.4. In Experiment 3, the effect of DNA-nicked spermatozoa on in vitro cleavage and blastocyst rates was evaluated, using 30 000 or 300 000 spermatozoa per droplet. Cleavage rate was adversely affected (P < 0.05) by DNA-nicked spermatozoa, regardless of sperm concentration. Blastocyst rate was lower (P < 0.05) in high DNA-nicked spermatozoa at the lower sperm concentration. In conclusion, the incidence of DNA-nicked spermatozoa is a useful marker to predict a bull’s fertility potential. DNA-nicked spermatozoa showed adverse effects on early embryonic development.

Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1675
Author(s):  
Jindong Hao ◽  
Siyi Huang ◽  
Dongxu Wang ◽  
Yongxun Jin ◽  
Mingjun Zhang ◽  
...  

m6A is one of the most common and abundant modifications of RNA molecules present in eukaryotes. The methyltransferase complex, consisting of methyltransferase-like 3 (METTL3), METTL14, and WTAP, is responsible for the m6A modification of RNA. WTAP was identified as an mRNA splicing regulator. Its role as a regulatory subunit of the m6A methyltransferase complex in embryonic development remains largely unknown. To investigate the role of WTAP in porcine early embryonic development, si-WTAP was microinjected into porcine parthenogenetic zygotes. WTAP knockdown significantly reduced the blastocyst rate and global m6A levels, but did not affect the cleavage rate. Betaine was supplemented into the in vitro culture (IVC) to increase the m6A levels. Betaine significantly increased the global m6A levels but did not affect the blastocyst rate. Furthermore, the pluripotency genes, including OCT4, SOX2, and NANOG, were downregulated following WTAP knockdown. The apoptotic genes BAX and CASPASE 3 were upregulated, while the anti-apoptotic gene BCL2 was downregulated in WTAP knockdown blastocysts. TUNEL staining revealed that the number of apoptotic cells was significantly increased following WTAP knockdown. Our study indicated that WTAP has an indispensable role in porcine early embryonic development.


2008 ◽  
Vol 20 (1) ◽  
pp. 135
Author(s):  
K. B. Lee ◽  
A. Bettegowda ◽  
J. J. Ireland ◽  
G. W. Smith

We have previously demonstrated a positive association of follistatin mRNA abundance with bovine oocyte competence. Furthermore, exogenous follistatin supplementation during the early stages of in vitro bovine embryo development (before embryonic genome activation) can reduce time to first cleavage, increase proportion of embryos developing to the blastocyst stage, and increase trophectoderm cell numbers, suggesting a potential role for follistatin in bovine early embryonic development. However, the requirement of endogenous follistatin for early embryogenesis in cattle has not been directly tested. Thus, the aim of the present study was to determine the requirement of follistatin for early embryonic development using small interfering RNA (siRNA)- based knockdown procedures. Small interfering RNA corresponding to exons 2 (siRNA 2) and 3 (siRNA 3) of the bovine follistatin gene were synthesized, and the optimal dose of each siRNA resulting in maximal reduction in follistatin mRNA (at the 4-cell stage) following microinjection into presumptive zygotes was determined. Injection of follistatin siRNA 2 or siRNA 3 resulted in a >80% decrease in follistatin mRNA abundance in 4-cell embryos, but mRNA abundance for 5 housekeeping genes and the oocyte-specific gene JY-1 was not affected. Effects of follistatin siRNA injection on follistatin protein abundance were evaluated by immunofluorescence staining of 16-cell embryos. Follistatin immunoreactivity was dramatically reduced in siRNA-treated v. uninjected embryos. Upon validation, the effects of follistatin siRNA on early embryonic development were investigated. Cumulus–oocyte complexes were harvested from ovaries obtained from a local abattoir, matured and fertilized in vitro. Sixteen to 18 h following fertilization, denuded presumptive zygotes (25–30 per treatment, n = 4 replicates) were microinjected with (1) follistatin siRNA 2, (2) negative control (nonspecific) siRNA, (3) sham (water), or (4) served as uninjected controls. After injections, embryos were cultured in KSOM medium supplemented with 0.3% BSA. Proportions of embryos reaching the 2-cell stage within 30 h (early cleaving), 30–36 h (late cleaving), and within 48 h post-fertilization (total cleavage rate) were recorded. Number of embryos reaching the 8–16-cell stage was recorded 72 h after fertilization, and embryos were cultured in fresh KSOM medium supplemented with 0.3% BSA and 10% fetal bovine serum until day 7. Injection of follistatin siRNA 2 did not affect proportion of early and late cleaving embryos (21 v. 19% and 41 v. 37%) and total cleavage rate (80 v. 81%). However, injection of follistatin siRNA 2 decreased the proportion of embryos reaching the 8–16-cell stage (41 v. 59%) and percentage blastocyst development (12 v. 27%, P < 0.05). Experiments were repeated, and effects of follistatin siRNA 3 determined (25–30 embryos per treatment, n = 4 replicates). Similar results were obtained as for follistatin siRNA 2 injection. Results support a requirement of endogenous follistatin for bovine early embryogenesis.


2019 ◽  
Author(s):  
Hua Xu ◽  
Xin Wang ◽  
Zhikai Wang ◽  
Jianhui Li ◽  
Zhiming Xu ◽  
...  

Abstract Background: MicroRNAs (miRNAs) are a class of noncoding small RNAs that play important roles in many physiological processes by regulating gene expression. Previous studies have shown that the expression levels of total miRNAs increase during mouse embryonic development, and some miRNAs control the regulatory network in development progression. However, few studies have focused on the effects of miRNAs on early human embryonic development. The relationship between miRNAs and early human embryogenesis is still unknown. Results:In this study, RNA-seq data collected from sperm samples from 102 patients with a normal sperm index but treated with assisted reproductive technology (ART) were analyzed for the relationships between differentially expressed small RNAs and the fertilization rate (FR), blastocyst rate and high-quality embryo rate (HQER). The sperm samples with high hsa-mir-191 expression had a higher FR, effective embryo rate (EER) and HQER. hsa-mir-191 was used as a single indicator to predict the HQER. The receiver operating characteristic (ROC) curve had an area under the ROC curve (AUC) of 0.686. We also found that hsa-mir-191 expression is correlated with an abnormal sperm rate (cor = 0.29, p< 0.01). We also evaluated the relationship between hsa-mir-34c and early human embryo development in these 102 sperm samples and obtained negative results. Conclusions: These findings suggest that high hsa-mir-191-5p expression in sperm is associated with early human embryonic quality and that hsa-mir-191-5p could be used as a potential marker to screen high-quality sperm to improve the success rates of in vitro fertilization (IVF).


2019 ◽  
Author(s):  
Hua Xu ◽  
Xin Wang ◽  
Zhikai Wang ◽  
Jianhui Li ◽  
Zhiming Xu ◽  
...  

Abstract Background : MicroRNAs (miRNAs) are a class of noncoding small RNAs that play important roles in many physiological processes by regulating gene expression. Previous studies have shown that the expression levels of total miRNAs increase during mouse embryonic development, and some miRNAs control the regulatory network in development progression. However, few studies have focused on the effects of miRNAs on early human embryonic development. The relationship between miRNAs and early human embryogenesis is still unknown. Results: In this study, sperm samples from 102 patients with a normal sperm index but treated with assisted reproductive technology (ART) were collected for small RNA sequencing, and the relationships between differentially expressed small RNAs and the fertilization rate (FR), blastocyst rate and high-quality embryo rate (HQER) were analyzed. The sperm samples with high hsa-mir-191 expression had a higher FR, effective embryo rate (EER) and HQER. hsa-mir-191 was used as a single indicator to predict the HQER. The receiver operating characteristic (ROC) curve had an area under the ROC curve (AUC) of 0.686. We also found that hsa-mir-191 expression is correlated with an abnormal sperm rate (cor = 0.29, p < 0.01). We also evaluated the relationship between hsa-mir-34c and early human embryo development in these 102 sperm samples and obtained negative results. Conclusions: These findings suggest that high hsa-mir-191-5p expression is associated with improved early human embryonic development and that hsa-mir-191-5p could be used as a potential marker to screen high-quality sperm to improve the success rates of in vitro fertilization (IVF).


1994 ◽  
Vol 9 (10) ◽  
pp. 1903-1908 ◽  
Author(s):  
Herman Tournaye ◽  
Marleen Van der Linden ◽  
Etienne Van den Abbeel ◽  
Paul Devroey ◽  
André Van Steirteghem

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