Survival of trophoblastic fragments and vesicles after vitrification, ultrarapid freezing, and storage at 4 degrees C.

Embryos recovered from superovulated cows on Day 13 or Day 17 of their sexual cycles were cut into fragments to make trophoblastic vesicles. The fragments were suspended in a cryoprotectant solution consisting of glycerol and sucrose and frozen by direct immersion into liquid nitrogen: alternatively, they were vitrified using the Massip method in a mixture of glycerol and 1,2-propanediol. Trophoblasts and fragments of a chilled embryo were placed into a temperature-controlled humidified chamber for culture. Vesicles which developed from trophoblastic fragments were subjected to vitrification according to the method of Massip. We observed good survival of trophoblastic fragments which had been subjected to chilling, freezing, or vitrification. Their survival did not differ from the survival of "fresh" trophoblastic fragments.