Multiple-embryo transfer for studying very early maternal-embryo interactions in cattle

Area of Science:

• Reproductive biology
• Embryology
• Maternal-fetal interactions

Background:

• Bovine species typically carry one embryo, with multiple pregnancies being rare.
• Studying early maternal-embryo interactions is crucial but challenging in monotocous species.
• Multiple-embryo transfer (MET) offers a non-physiological model to investigate these interactions.

Purpose of the Study:

• To highlight the necessity of studying very early maternal-embryo interactions.
• To discuss methodologies for addressing these interactions.
• To validate MET as a tool for studying early embryo-maternal crosstalk in cattle.

Main Methods:

• Utilizing cattle as a model system.
• Employing multiple-embryo transfer (MET) to simulate higher-order pregnancies.
• Applying transcriptomics, proteomics, and endometrial cell culture to analyze molecular changes.

Main Results:

• The uterus does not exhibit non-physiological reactions to zona-enclosed embryos in early MET.
• MET effects are the sum of individual embryo-triggered responses.
• Technical approaches identified molecular changes difficult to observe with single embryos.

Conclusions:

• Multiple-embryo transfer (MET) is a viable method for studying very early maternal-embryo interactions in vivo.
• This approach aids in understanding endometrial responses in monotocous species.
• MET provides insights into molecular dynamics crucial for reproductive success.