Quality Of Somatic Cell Nuclear Transfer Embryos Research Articles

A long non-coding RNA essential for early embryonic development improves SCNT efficiency in goats.

Although abundant long non-coding RNAs (lncRNAs) have been found to be highly expressed in early embryos, the functions and mechanisms of most lncRNAs in regulating embryonic development remain unclear. This study was conducted to identify the key lncRNAs during embryonic genome activation (EGA) for promoting embryonic development after somatic cell nuclear transfer (SCNT) in goats. We screened and characterized lncRNAs from transcriptome data of in vitro-fertilized, 2-cell (IVF-2c) and 8-cell embryos (IVF-8c) and 8-cell SCNT embryos (SCNT-8c). We obtained 12 differentially expressed lncRNAs that were highly expressed in IVF-8c embryos compared to IVF-2c, and less expressed in SCNT-8c embryos. After target gene prediction, expression verification, and functional deletion experiments, we found that the expression level of lncRNA3720 affected the early embryonic development in goats. We cloned full length lncRNA3720 and over-expressed it in goat fetal fibroblasts (GFFs). We identified histone variants by analyzing the transcriptome data from both GFFs and embryos. Gene annotation of the gene library and literature search revealed that histone variants may have important roles in early embryo development, so we selected them as the potential target genes for lncRNA3720. Lastly, we compensated for the low expression of lncRNA3720 in SCNT embryos by microinjection, and showed that the development rate and quality of SCNT embryos was significantly improved. We speculate that lncRNA3720 is a key promoter of embryonic development in goats by interacting with histone variants.

Treatments of Porcine Nuclear Recipient Oocytes and Somatic Cell Nuclear Transfer-Generated Embryos with Various Reactive Oxygen Species Scavengers Lead to Improvements of Their Quality Parameters and Developmental Competences by Mitigating Oxidative Stress-Related Impacts.

This study investigated the antioxidant effects of β-cryptoxanthin (BCX), hesperetin (HES), and icariin (ICA), and their effects on in vitro maturation of porcine oocytes and subsequent embryonic development of somatic cell nuclear transfer (SCNT). Treatment with 1 μM BCX (BCX-1) increased the developmental rate of porcine oocytes more than treatment with 100 μM HES (HES-100) or 5 μM ICA (ICA-5). The glutathione level and mRNA expression of antioxidant genes (NFE2L2, SOD1, and SOD2) were more increased in the BCX-1 group than in the HES-100 and ICA-5 groups, while the reactive oxygen species level was more decreased. Moreover, BCX improved the developmental capacity and quality of SCNT embryos. The total cell number, apoptotic cell rate, and development-related gene expression were modulated in the BCX-1 group to enhance embryonic development of SCNT. These results show that the antioxidant effects of BCX enhance in vitro maturation of porcine oocytes and subsequent embryonic development of SCNT.

Effect of Epigallocatechin-3-Gallate on the In Vitro Developmental Potential of Porcine Oocytes and Embryos Obtained Parthenogenetically and By Somatic Cell Nuclear Transfer

The present study aimed to investigate the effects of epigallocatechin-3-gallate (EGCG) on the in vitro development of porcine oocytes, parthenogenetic activation embryos (PA), and somatic cell nuclear transfer (SCNT) embryos. In Experiment 1, 0 (control), 10, 30, and 50 μg/mL EGCG were added to in vitro maturation (IVM) medium to explore the effect of EGCG on IVM of pig oocytes. The matured oocytes were then used to produce PA and SCNT embryos. Either for nuclear maturation of oocytes or for the rates of cleavage and blastocyst of PA and SCNT embryos, no significant difference was found among all groups. However, the total cell number per cloned blastocyst was significantly lower in blastocysts derived from oocytes matured in 50 μg mL EGCG (P<0.05) as compared with the other groups. In Experiment 2, we cultured pig SCNT and PA embryos in medium containing various concentrations of EGCG to examine the effect of EGCG on preimplantation development. The cleavage and blastocyst rates and the total cell number per blastocyst did not significantly differ between PA and SCNT embryos among all groups. However, the reactive oxygen species level was significantly lower in the PA embryos cultured in 10 μg mL EGCG than the other groups (P<0.05). Our results suggest that high doses of EGCG in IVM are harmful to the oocytes as evidenced by the decreased quality of SCNT embryos, and EGCG has no beneficial effects on in vitro development of pig cloned embryos.