Comparison Between Direct Plunging and Vitrification Techniques on Development of Mouse Embryos at Various Preimplantation Stages

Abstract

This study evaluated the efficiency of direct plunging and vitrification techniques in preserving mouse embryos at various preimplantation stages. Embryos were from superovulated ICR female mice. In direct plunging, embryos were equilibrated in EG (4.0 M), sucrose (0.25 M), BSA (4%), loaded into straw and plunged into LN(2). The straw was thawed in water bath (37 degrees C) and embryos were equilibrated in sucrose (0.5 M), BSA (4%). In vitrification, embryos were equilibrated with EG (7.5%), DMSO (7.5%) with EG (15%), DMSO (15%) and loaded onto cryoleaf. The cryoleaf was plunged into LN(2). Embryos were warned in sucrose (1.0 M), sucrose (0.5 M), washing solution and in modified WM medium. Frozen-thawed/vitrified-warmed embryos were cultured in modified WM medium in 5% CO(2) incubator (37 degrees C). Some embryos were transferred into pseudopregnant CBA/ca females for in vivo viability assessment. Vitrification gave higher survival rates than direct plunging technique at all developmental stages studied. No significant differences in the percentage of live-birth from direct plunging (22.40 +/- 4.40%), vitrification (29.80 +/- 9.00%) and control embryos (28.83 +/- 3.25%).