Effect of Different Media and Protein Source on Equine Gametes: Potential Impact During In Vitro Fertilization.

This study examines the inconsistency observed in equine in vitro fertilization (IVF) and tests the impact different media and proteins have on equine gametes during IVF. More specifically, it studies how modified Whitten’s medium, Tissue Culture Medium 199, Foetal Bovine Serum, and Bovine Serum Albumin affect equine oocytes and sperm, and their potential impact on IVF results.

Research Methodology

• The researchers classified equine oocytes into two groups: Compact (Cp) and expanded (Ex) cumuli equine oocytes.
• These oocytes were then matured and placed in two types of media – Tissue Culture Medium 199 (TCM) and modified Whitten’s (MW) medium – for a span of 18-20 hours, each supplemented with either Bovine Serum Albumin (BSA) or Foetal Bovine Serum (FBS).
• Equine sperm were then capacitated in the same types of media at a concentration of 10 × 10(6) sperm/ml for 4 hours at a controlled temperature of 37 degrees Celsius.
• The team assessed total motility and protein tyrosine phosphorylation in the capacitated sperm.

Research Findings

• In the case of Ex oocytes, those placed in TCM-199 and accompanied with either FBS or BSA demonstrated higher metaphase II rates compared to MW poached oocytes supplemented with BSA or FBS.
• This enhancement, however, was not observed in the Cp oocyte group.
• While there was no change in sperm motility, TCM or MW supplemented with FBS showed a substantial increase in the number of sperm exhibiting protein tyrosine phosphorylation (PY) compared to media supplemented with BSA.
• However, despite these positive findings on oocyte maturity and sperm functions, when researchers ran the actual IVF trials—using the same media supplemented with 200ng/ml of progesterone—no fertilization occurred.

Conclusion and Implications

• The study concluded that TCM supplemented with FBS had a more positive impact on Expanded equine oocyte’s aptitude for meiosis than when MW was supplemented with BSA.
• It additionally discovered that the inclusion of FBS in either TCM or MW successfully induced equine PY, more than media supplemented with BSA.
• These findings have implications for the procedures, media, and protein sources used in equine IVF practices, potentially providing direction for researchers hoping to solve the inconsistencies in equine in vitro fertilization.