Abstract
Embryo aggregation is a useful method to produce blastocysts with high developmental competence to generate more offspring in various mammals, but the underlying mechanism(s) regarding the beneficial effects are largely unknown. In this study, we investigated the effects of embryo aggregation using 4-cell stage embryos in in vitro developmental competence and the relationship of stress conditions in porcine early embryogenesis. We conducted aggregation using the well of the well system and confirmed that aggregation using two or three embryos was useful for obtaining blastocysts. Aggregated embryos significantly improved developmental competence, including blastocyst formation rate, blastomere number, ICM/TE ratio, and cellular survival rate, compared to non-aggregated embryos. Investigation into the relationship between embryo aggregation and stress conditions revealed that mitochondrial function increased, and oxidative and endoplasmic reticulum (ER)-stress decreased compared to 1X (non-aggregated embryos) blastocysts. In addition, 3X (three-embryo aggregated) blastocysts increased the expression of pluripotency, anti-apoptosis, and implantation related genes, and decreased expression of pro-apoptosis related genes. Therefore, these findings indicate that embryo aggregation regulates in vitro stress conditions to increase developmental competence and contributes to the in vitro production of high-quality embryos and the large-scale production of transgenic and chimeric pigs.
Highlights
Pigs are useful experimental animal models because of their close anatomic, genetic, and physiological similarities with humans (Lunney, 2007)
We demonstrated that developmental competence increased in porcine in vitro-produced (IVP) embryos by embryo aggregation via reducing the stress conditions and improving mitochondrial function
We showed similar results in which the embryo aggregation method was adequate for 4-cell stage embryos, significantly enhancing key parameters of developmental competence, such as blastocyst formation rate, total cell number, ICM/TE ratio, cellular survival and expression of pluripotency, apoptosis, and implantation related genes
Summary
Pigs are useful experimental animal models because of their close anatomic, genetic, and physiological similarities with humans (Lunney, 2007). In vitro-produced (IVP) embryos remain inferior in terms of developmental competence, including blastocyst formation rate, blastomere number and survival rate, compared to their in vivo counterparts (Koo et al, 2004). Mitochondria are key regulators of cellular energy and act as storage facilities for calcium ions. They are associated with eukaryotic cellular differentiation, cell death, and growth (McBride, Neuspiel & Wasiak, 2006). Other studies have demonstrated that mitochondrial membrane potential, an indicator of cellular metabolic activity, is an important determinant for fertilization and pre-implantation embryonic development in pigs and mice (Romek et al, 2011; Wakefield, Lane & Mitchell, 2011)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
