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Home / Equine Research Bank / Int J Mol Sci / In Vitro-Produced Equine Blastocysts Exhibit Greater Dispers...
International journal of molecular sciences2023; 24(11); 9619; doi: 10.3390/ijms24119619

In Vitro-Produced Equine Blastocysts Exhibit Greater Dispersal and Intermingling of Inner Cell Mass Cells than In Vivo Embryos.

Abstract: In vitro production (IVP) of equine embryos is increasingly popular in clinical practice but suffers from higher incidences of early embryonic loss and monozygotic twin development than transfer of in vivo derived (IVD) embryos. Early embryo development is classically characterized by two cell fate decisions: (1) first, trophectoderm (TE) cells differentiate from inner cell mass (ICM); (2) second, the ICM segregates into epiblast (EPI) and primitive endoderm (PE). This study examined the influence of embryo type (IVD versus IVP), developmental stage or speed, and culture environment (in vitro versus in vivo) on the expression of the cell lineage markers, CDX-2 (TE), SOX-2 (EPI) and GATA-6 (PE). The numbers and distribution of cells expressing the three lineage markers were evaluated in day 7 IVD early blastocysts ( = 3) and blastocysts ( = 3), and in IVP embryos first identified as blastocysts after 7 (fast development, = 5) or 9 (slow development, = 9) days. Furthermore, day 7 IVP blastocysts were examined after additional culture for 2 days either in vitro ( = 5) or in vivo (after transfer into recipient mares, = 3). In IVD early blastocysts, SOX-2 positive cells were encircled by GATA-6 positive cells in the ICM, with SOX-2 co-expression in some presumed PE cells. In IVD blastocysts, SOX-2 expression was exclusive to the compacted presumptive EPI, while GATA-6 and CDX-2 expression were consistent with PE and TE specification, respectively. In IVP blastocysts, SOX-2 and GATA-6 positive cells were intermingled and relatively dispersed, and co-expression of SOX-2 or GATA-6 was evident in some CDX-2 positive TE cells. IVP blastocysts had lower TE and total cell numbers than IVD blastocysts and displayed larger mean inter-EPI cell distances; these features were more pronounced in slower-developing IVP blastocysts. Transferring IVP blastocysts into recipient mares led to the compaction of SOX-2 positive cells into a presumptive EPI, whereas extended in vitro culture did not. In conclusion, IVP equine embryos have a poorly compacted ICM with intermingled EPI and PE cells; features accentuated in slowly developing embryos but remedied by transfer to a recipient mare.
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Publication Date: 2023-06-01 PubMed ID: 37298570PubMed Central: PMC10253440DOI: 10.3390/ijms24119619Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research demonstrates that equine blastocysts created in laboratory settings, or in vitro, show greater dispersion and mixture of inner cell mass (ICM) cells compared to those developed naturally inside the horse’s body, or in vivo. The research also indicates that in vitro produced (IVP) embryos fare worse in terms of early embryonic loss and twin development compared to the in vivo derived (IVD) counterparts.

Key Objectives and Methodology of the Research

  • The objective of the study was to understand how embryo type (in vitro versus in vivo), developmental speed, and culture conditions affect the expression of certain cell lineage markers, CDX-2, SOX-2, and GATA-6, which identify different types of cells in early embryo development.
  • The study gathered data by analyzing two groups of blastocysts. The first group consisted of those which were IVD, and the second, those which were IVP. The cell expression of lineage markers in each group was then studied on day 7.
  • The researchers also observed what changes took place in the IVP embryos post an additional two days of in vitro culture, and what changes occurred post transferring the same into recipient mares.

Key Findings and Inferences

  • For the IVD group, on day 7, SOX-2 positive cells were seen enclosed by GATA-6 positive cells in the ICM. Some primitive endoderm (PE) cells also co-expressed SOX-2.
  • In the same group, on day 7, SOX-2 was uniquely expressed by compacted presumptive epiblast (EPI), while GATA-6 and CDX-2 expressions were associated with PE and trophectoderm (TE) specification, in that order.
  • For the IVP group, on day 7, SOX-2 and GATA-6 positive cells were intermixed and relatively scattered. There were also some TE cells that co-expressed either SOX-2 or GATA-6.
  • IVP embryos also showed lower TE and total cell numbers compared to IVD ones, and larger mean distances between EPI cells—factors that were even more significant in the slowly developing IVP embryos.
  • On the transfer of the IVP embryos into recipient mares, SOX-2 positive cells compacted into a presumptive EPI. However, extended in vitro culture did not yield the same results.

Conclusion

  • The study has concluded that in vitro produced (IVP) equine embryos display a poorly compacted ICM, with intermingled EPI and primitive endoderm (PE) cells.
  • This observation is even more prominent in slowly developing embryos. However, this issue can be corrected by transferring the IVP embryo to a recipient mare.

Cite This Article

APA
Umair M, Scheeren VFDC, Beitsma MM, Colleoni S, Galli C, Lazzari G, de Ruijter-Villani M, Stout TAE, Claes A. (2023). In Vitro-Produced Equine Blastocysts Exhibit Greater Dispersal and Intermingling of Inner Cell Mass Cells than In Vivo Embryos. Int J Mol Sci, 24(11), 9619. https://doi.org/10.3390/ijms24119619

Publication

International journal of molecular sciences
ISSN: 1422-0067
NlmUniqueID: 101092791
Country: Switzerland
Language: English
Volume: 24
Issue: 11
PII: 9619

Researcher Affiliations

Umair, Muhammad
  • Department of Clinical Sciences, Faculty of Veterinary Medicine, Utrecht University, 3584 CM Utrecht, The Netherlands.
Scheeren, Veronica Flores da Cunha
  • Department of Clinical Sciences, Faculty of Veterinary Medicine, Utrecht University, 3584 CM Utrecht, The Netherlands.
Beitsma, Mabel M
  • Department of Clinical Sciences, Faculty of Veterinary Medicine, Utrecht University, 3584 CM Utrecht, The Netherlands.
Colleoni, Silvia
  • Avantea srl, Via Porcellasco 7/F, 26100 Cremona, Italy.
Galli, Cesare
  • Avantea srl, Via Porcellasco 7/F, 26100 Cremona, Italy.
Lazzari, Giovanna
  • Avantea srl, Via Porcellasco 7/F, 26100 Cremona, Italy.
de Ruijter-Villani, Marta
  • Department of Clinical Sciences, Faculty of Veterinary Medicine, Utrecht University, 3584 CM Utrecht, The Netherlands.
Stout, Tom A E
  • Department of Clinical Sciences, Faculty of Veterinary Medicine, Utrecht University, 3584 CM Utrecht, The Netherlands.
Claes, Anthony
  • Department of Clinical Sciences, Faculty of Veterinary Medicine, Utrecht University, 3584 CM Utrecht, The Netherlands.

MeSH Terms

  • Animals
  • Horses
  • Female
  • Blastocyst / metabolism
  • Embryo, Mammalian
  • Germ Layers
  • Cell Differentiation
  • Embryonic Development

Grant Funding

  • (PEEF/SSMS/18/222). / Punjab Educational Endowment Fund (PEEF), Punjab, Pakistan

Conflict of Interest Statement

The authors declare no conflict of interest.

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