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Context. In vitro maturation is an important process in the production of embryos. It has been shown that three cytokines, fibroblast growth factor 2, leukemia inhibitory factor and insulin-like growth factor 1 (FLI), increased efficiency of in vitro maturation,somatic cell nucleartransfer(SCNT) blastocyst production, and in vivo development of genetically engineered piglets. Aims. Assess effects of FLI on oocyte maturation, quality of oocytes, and embryo development in bovine in vitro fertilisation (IVF) and SCNT. Key results. Cytokine supplementation resulted in significant increases in maturation rates and decreased levels of reactive oxygen species. Oocytes matured in FLI had increased blastocyst rates when used in IVF (35.6% vs 27.3%, P < 0.05) and SCNT (40.6% vs 25.7%, P < 0.05). SCNT blastocysts contained significantly more inner cell mass and trophectodermal cells when compared to the control group. Importantly, SCNT embryos derived from oocytes matured in FLI medium resulted in a four-fold increase in full-term development compared to control medium (23.3% vs 5.3%, P < 0.05). Relative mRNA expression analysis of 37 genes associated with embryonic and fetal development revealed one gene had differential transcript abundance in metaphase II oocytes, nine genes at the 8-cell stage, 10 genes at the blastocyst stage in IVF embryos and four genes at the blastocyst stage in SCNT embryos. Conclusions. Cytokine supplementation increased efficiency of in vitro production of IVF and SCNT embryos and in vivo development of SCNT embryos to term. Implications. Cytokine supplementation is beneficial to embryo culture systems, which may shed light on requirements of early embryo development. [ABSTRACT FROM AUTHOR]

Context: Male exposure to environmental toxicants can disrupt spermatogenesis and sperm function. However, consequences of environmentally relevant organotin exposure to post-ejaculatory mammalian spermatozoa on fertility are poorly understood. Aims: Determine the consequences of tributyltin chloride (TBT) exposure on post-ejaculatory sperm function and subsequent embryo development. Methods: Frozen-thawed bovine sperm were exposed to TBT (0.1–100 nM) for 90 min (acute) and 6 h (short-term) followed by quantification of multiple sperm kinematics via computer aided sperm analysis. JC-1 dye was used to measure mitochondrial membrane potential. Sperm were then exposed to TBT for 90 min in non-capacitating conditions, washed several times by centrifugation and applied to gamete co-incubation for in vitro embryo production to the blastocyst stage. Key results: 100 nM TBT decreased total motility (88 vs 79%), progressive motility (80 vs 70%) curvilinear velocity and beat-cross frequency for 90 min with similar phenotypes at 6 h (P < 0.05). Sperm mitochondrial membrane potential was lower in 10 and 100 nM groups after 6 h (P ≤ 0.05). Embryos fertilised from TBT-exposed sperm had reduced cleavage rate (80 vs 62%) and 8–16 cell morula development (55 vs 24%) compared to development from unexposed sperm. Conclusions: Exposure of post-ejaculatory mammalian sperm to TBT alters sperm function through lowered motility and mitochondrial membrane potential. Fertilisation of oocytes with TBT-exposed sperm reduces embryo development through mechanisms of paternal origin. Implications: Acute and short-term environmental exposure of post-ejaculatory sperm to organotins and endocrine disrupting chemicals such as TBT contribute to idiopathic subfertility and early embryo loss. Environmental contaminant exposure to humans and animals is a global concern for negative effects on reproductive health and fertility. Consequences of the common and environmentally stable compound tributyltin chloride on post-ejaculatory sperm exposure were previously unknown and established herein to alter sperm function through reducing embryo development. These findings indicate that short-term exposure to environmental contaminants impact male fertility through a mechanism of paternal origin that negatively alters embryo development. [ABSTRACT FROM AUTHOR]

Context: Maternal-effect genes (MEGs) play a critical role in modulating both cellular and molecular biology events in preimplantation embryonic development. Damage-specific DNA binding protein 1 (DDB1) is a gene that participates in meiotic resumption, ovulation, and embryonic stem cell maintenance. Its function in preimplantation development is not well-studied. Aims: We aimed to explore the expression pattern, genomic heritage, and potential molecular mechanisms of DDB1 in preimplantation embryos in porcine. Methods: In this study, RNA interference, microinjection, RT-qPCR, immunofluorescence staining and single-cell RNA sequencing were used to explore the molecular function of DDB1 in porcine preimplantation embryos. Key results: DDB1 was found to be expressed in germinal vesicle (GV) and Meiosis II (MII) oocytes and in preimplantation embryos. We confirmed it is a MEG. DDB1 -deficient blastocysts had a significantly reduced number of trophectoderm cells, an increased apoptotic cell number and increased apoptosis index. According to a next-generation sequencing (NGS) analysis, 236 genes (131 upregulated and 105 downregulated) significantly changed in the DDB1 -deficient morula. The myeloid leukaemia factor 1 (MLF1) and yes-associated protein 1 (YAP1) expressions were significantly upregulated and downregulated respectively, in the DDB1 -deficient morula. In combination with the decreased expression of TEAD4 , CDX2 , GATA3 , OCT4 , and NANOG and the increased expression of SOX2 in the blastocyst, DDB1 may play a role in determining lineage differentiation and pluripotency maintenance. Conclusions: DDB1 is a MEG and it plays a crucial role in porcine preimplantation embryonic development. Implications: This study provides a theoretical basis for further understanding the molecular mechanisms of preimplantation embryo development. DDB1 is a gene that participates in meiotic resumption, ovulation, and embryonic stem cell maintenance. It is produced from maternal origin transcripts in early porcine embryos. DDB1 -deficiency enhanced cellular apoptosis in the blastocyst. Lack of DDB1 impaired trophectoderm formation and the pluripotency maintenance of blastocyst. DDB1 is a MEG, which plays a the crucial role of in porcine preimplantation embryonic development. [ABSTRACT FROM AUTHOR]