投入液氮前的平衡温度及时间对兔胚冻后存活的影响

本研究旨在了解投入液氮前的平衡温度及时间对兔胚冻后存活的影响。经0.5M蔗糖与1.5,2.0或2.5M乙二醇组成的冷冻液处理后的兔胚,在-30℃或-37℃平衡10或20分钟后即投入液氮保存或直接投入液氮保存。胚胎解冻在37℃的水浴进行。当平衡温度由-30℃下降到-37℃时,胚胎的冻后形态正常率及存活率均极显著下降(P<0.01)。在-30℃平衡20分钟与10分钟的冻后存活率无明显差异(P>0.05),但直接投入液氮时,冻后存活率则很低(8.3％)。由此表明:兔胚冻前在-30℃平衡10—20分钟是必要的。

Effects of the Equilibrating Temperure and Duratation before Cooling to Liquid Nitrogen on the Survival of Rabbit Embryos Frozen by Two Steps

The rabbit embryos teated with one of the three freezing media consisting of 0.5 M sucrose and 1.5, 2.0 or 2.5 M ethylene glycol in PB1 were directly cooled to -30 or -37°C with a holding time of 20 or 10 min at this temperature before immersion into liquid nitrogen or directly cooled to liquid nitrogen, and rapidly thawed in a waterbath at 37°C.Decrease of the equilibrating temperature from -30°C down to -37°C resulted in a significant decrease in either morpho-logicaly normal rate or survival rate(p<0.05).when the equilibrating duration at-30°C was shortened from 20 min to 10 min, the survival rate of embryos thawed did not change obviously, but very few of embryos (8.3%) survived when the embryos were directly cooled to liquid nitrogen. These results indicate that the rabbit embryos should be equilibrated at -30°C for 10-20 min before cooling to liuqid nitrogen.