Studies on the Effects of Ethylene glycol on the Survival of Frozen-Thawed Mouse Embryos

Jo, Choong-ho; Cheong, Chang-kook; Hwang, Woo-suk

Korean Journal of Veterinary Research 1987;27(2):331-334.

Choong-ho Jo, Chang-kook Cheong, Woo-suk Hwang

College of Veterinary Medicine, Seoul National University

Mouse수정란(受精卵)의 동결(凍結), 융해(融解)에 있어 Ethylene glycol의 효과(效果)에 관(關)한 연구(硏究)

조충호, 정창국, 황우석

서울대학교 수의과대학

Abstract

The effects of ethylene glycol as a cryoprotective agent on the survival of frozen-thawed mouse embryos were examined. The effects of the stage of development of ethylene glycol were also examined. Eight-cell embryos, morulae, early blastocysts and mid-blastocysts were recovered from superovulated immature ddY mice. Ethylene glycol was added to the embryos in 5 equal increments 5 minutes apart, giving a final concentration of 1.5M. The embryos were cooled to ${-6^{circ}C}$ at ${1^{circ}C/min}$ and seeding was induced at ${-6^{circ}C}$. After being held for a further 5minutes at the seeding temperature, the samples were cooled to ${-35^{circ}C}$ at ${0.3^{circ}C/min}$ and then transferred to liquid nitrogen. Rapid thawing was done by placing the straws in ${37^{circ}C}$ water. The thawed embryos were diluted in PBS of same time and manners as adding procedures. Survival of 8-cell embryos and morulae were assessed as a normal development of the embryos to the blastocyst stage and expanding blastocyst after 54 hours and 48 hours of in vitro culture, respectively. While those of the early and mid-blastocysts were assessed to the expanding blastocyst stage after 24 hours of in vitro culture. The survival rates of 8-cell embryos, morulae, early blastocysts and mid-blastocysts were 73.8%, 74.3%, 87.8% and 77.4%, respectively. Significant difference on the survival rate among the four stages of development was not observed.