Bovine 1-2-cell embryo development using a simple medium in three oviduct epithelial cell coculture systems

Area of Science:

• Reproductive Biology
• Embryology
• Animal Science

Background:

• Early bovine embryo development is crucial for reproductive success.
• Current coculture systems often require complex media and may not optimize development.
• Bovine oviduct epithelial cells (BOEC) are a potential component for improved embryo culture.

Purpose of the Study:

• To develop a simple, effective coculture system for early bovine embryos.
• To evaluate the impact of different media and BOEC conditions on embryo development.
• To optimize conditions for achieving morula and blastocyst stages.

Main Methods:

• Coculture of in vivo-fertilized 1-2 cell bovine embryos using bovine oviduct epithelial cells (BOEC).
• Comparison of a simple glucose-free, serum-free medium (CZB) against commercial media (Ham's F-10, CMRL-1066).
• Evaluation of fresh vs. frozen-thawed BOEC monolayers and BOEC-conditioned medium.
• Assessment of glucose presence during early culture stages.

Main Results:

• The simple CZB medium with fresh BOEC monolayers yielded superior embryo quality and development.
• Embryos cultured with fresh BOEC monolayers had significantly higher cell counts than those with frozen-thawed BOEC or conditioned medium.
• Absence of glucose in the initial 48 hours of culture increased blastulation rates.
• A trend towards increased hatching was observed in BOEC coculture.

Conclusions:

• A chemically simple medium combined with fresh BOEC monolayers significantly benefits early bovine embryo development.
• This optimized coculture system promotes development to morula and blastocyst stages.
• The findings offer a more efficient approach for bovine embryo culture and assisted reproductive technologies.