LAUSR

High concentrations of cryoprotective agents (CPAs) used for vitrification of equine oocytes and porcine embryos are believed to negatively affect developmental competence. Here, osmotic events were simulated using 2P formalism (Kleinhans, Cryobiology 37, 271–289) to predict effects of reduced duration of CPA exposure and effects of use of non-permeating CPAs. Varying concentrations of permeating CPAs (ethane-1,2-diol and Me2SO) were used in the first step (equilibration solution, ES) and second step (vitrification solution, VS). In VS, varying concentrations of additional non-permeating solute (sucrose) were used. The duration of the first step (ES) was varied between 0.5-10 min, while exposure to VS was 0.51 min. Values for Lp and Ps were based on published values for oocytes and embryos respectively.