Study on effectiveness of vitrificaiton using Electron Microscope(EM) Grid in mice embryo cryopreservation = 생쥐 수정란의 동결보존시 Electron Microscope(EM) Grid를 이용한 초자화동결법의 효용성에 관한 연구

Abstract

This present study was conducted to examine the effectiveness of vitrification by electron microscope (EM) grid in cryopreservation of mouse 2cell embryos. A total of 2,744 mouse 2-cell embryos were used, and the rate of survival and development in vitro after freezing-thawing by three different cryopreservation methods were comparatively examined. In the experiment of only exposure on freezing and thawing solution, the survival rates of 2-cell mice embryos were not significant difference between vitrification method (VM) I and II (90.4% and 93.3%, respectively), and also, the rates of development into blastocyst were not significant difference between two groups (76.4% and 78.0%, respectively) after 72h in culture in vitro. The survival rates of frozen-thawed embryos between slow-freezing (81.8%), VM I (76.5%) and II (82.7%) were not significances. In the developmental rate into blastocyst, VM II was highest between three experimental groups, but there were no significances. Using VM II at room temperature, in the rates of survival and development into blastocyst by exposure time of embryos on freezing solutions, the embryos exposed for 3 min in EG20 and then 0.5 min in EFS40 were revealed highest (83.1% and 74.1%, respectively) except for control. However, at 37oC, in the rates of survival and development into blastocyst, the embryos exposed for 2 min in EG20 and then 0.5 min in EFS40 was revealed highest (80.2% and 74.1%, respectively) except for control. In the survival rate by exposure time of embryos on thawing solutions, the embryos exposed sequentially intervals 1.5 min was highest (84.3%), however, in the developmental rate into blastocyst, the embryos exposed sequentially intervals 2 min was highest (74.6%).