title: Two-step freezing of two-cell rabbit embryos after partial dehydration at room temperature.
abstract: The effect of rapid freezing and thawing on the survival of 2-cell rabbit embryos was examined. When embryos in 2.2 M-propanediol were directly plunged from room temperature to liquid nitrogen some of them survived after thawing (8%) but only if they had been pretreated by exposure to an impermeable solute, sucrose, that makes the blastomeres shrink osmotically before cooling. High survival (77-88%) in vitro was obtained when pretreated embryos were first held at -30 degrees C for 30-240 min before immersion into liquid nitrogen. Transfer of such frozen-thawed embryos gave a survival rate to live young similar to that obtained with controls (26% and 32% respectively). DMSO was less effective than propanediol; only 2 out of 38 sucrose-pretreated frozen-thawed embryos developed in vitro. The present work shows that a combination of partial dehydration of blastomeres at room temperature with their permeation by a cryoprotective agent offers a simple method for successful rapid freezing and thawing of rabbit embryos.
mesh_terms: D000818:Animals; D001757:Blastomeres; D003890:Desiccation; D004624:Embryo Transfer; D005260:Female; D005615:Freezing; D019946:Propylene Glycol; D011409:Propylene Glycols; D011817:Rabbits; D013395:Sucrose; D014021:Tissue Preservation / Q000379:methods*
chemical_list: D011409:Propylene Glycols; D013395:Sucrose; D019946:Propylene Glycol