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

Abstract

To determine whether modified TES and Tris (TEST) yolk buffer (TYB) made using a commercially available egg yolk extract would exhibit lab performance characteristics equal to the existing preparation made with whole egg yolk and to define the phospholipid content of the new modified TYB formulation. Divided ejaculates from 21 normozoospermic and 7 oligozoospermic males presenting for pre-IVF evaluation were stored at 0 to 4 degrees C for 42 hours using commercially available or modified TYB before analysis in the optimized sperm penetration assay (SPA). A commercial tissue culture manufacturer and a clinical fertility reference laboratory. Sperm swim-up recoveries and average penetrations per ovum, determined by the SPA, were used as measures of sperm function. High-pressure liquid chromatography (HPLC) was used to profile the egg yolk extract. No significant differences in either sperm swim-up recovery rates or SPA results were found in normal or poor quality semen that was treated with modified or commercial TYB. The major constituent in commercial egg yolk extract is lecithin. Commercially available egg yolk extract passes easily through a 0.2-microns filter, is a rich source of lecithin, and can be substituted effectively for whole egg yolk in preparing TYB.