A simple method for preparing modified TES and Tris yolk buffer that is optically clear and membrane filterable

Area of Science:

• Reproductive biology
• Sperm function analysis
• Biochemical analysis of media

Background:

• Traditional TES and Tris (TEST) yolk buffer (TYB) is crucial for sperm preparation in assisted reproduction.
• The preparation of TYB traditionally uses whole egg yolk, posing potential variability and challenges.
• Evaluating alternative, standardized components for TYB is essential for consistent laboratory performance.

Purpose of the Study:

• To assess the laboratory performance of a modified TYB using a commercial egg yolk extract.
• To compare the efficacy of modified TYB with the traditional whole egg yolk TYB.
• To characterize the phospholipid content, specifically lecithin, of the modified TYB formulation.

Main Methods:

• Sperm samples from normozoospermic and oligozoospermic males were stored in modified or commercial TYB.
• Sperm function was evaluated using the optimized sperm penetration assay (SPA).
• Sperm swim-up recovery rates and average ovum penetration were measured; HPLC analyzed egg yolk extract composition.

Main Results:

• No significant differences were observed in sperm swim-up recovery rates between modified and commercial TYB.
• Optimized sperm penetration assay (SPA) results were comparable for both TYB preparations across different semen qualities.
• High-pressure liquid chromatography (HPLC) identified lecithin as the primary component of the commercial egg yolk extract.

Conclusions:

• Commercially available egg yolk extract is a rich source of lecithin and can be filtered (0.2-microns).
• Modified TYB prepared with egg yolk extract demonstrates equivalent performance to whole egg yolk TYB.
• The commercial egg yolk extract serves as an effective and potentially more standardized substitute for whole egg yolk in TYB preparation.