Vitrification of mouse embryos using the thin plastic strip method.
OBJECTIVE
The aim of this study was to compare vitrification optimization of mouse embryos using electron microscopy (EM) grid, cryotop, and thin plastic strip (TPS) containers by evaluating developmental competence and apoptosis rates.


METHODS
Mouse embryos were obtained from superovulated mice. Mouse cleavage-stage, expanded, hatching-stage, and hatched-stage embryos were cryopreserved in EM grid, cryotop, and TPS containers by vitrification in 15% ethylene glycol, 15% dimethylsulfoxide, 10 µg/mL Ficoll, and 0.65 M sucrose, and 20% serum substitute supplement (SSS) with basal medium, respectively. For the three groups in which the embryos were thawed in the EM grid, cryotop, and TPS containers, the thawing solution consisted of 0.25 M sucrose, 0.125 M sucrose, and 20% SSS with basal medium, respectively. Rates of survival, re-expansion, reaching the hatched stage, and apoptosis after thawing were compared among the three groups.


RESULTS
Developmental competence after thawing of vitrified expanded and hatching-stage blastocysts using cryotop and TPS methods were significantly higher than survival using the EM grid (p<0.05). Also, apoptosis positive nuclei rates after thawing of vitrified expanded blastocysts using cryotop and TPS were significantly lower than when using the EM grid (p<0.05).


CONCLUSIONS
The TPS vitrification method has the advantages of achieving a high developmental ability and effective preservation.
Maria Fertility Hospital, Seoul, Korea.
Eun Kyung
EK
Ryu
Yong Soo
YS
Hur
Ji Young
JY
Ann
Ja Young
JY
Maeng
Miji
M
Park
Jeong Hyun
JH
Park
Jung
J
Yoon
San Hyun
SH
Yoon
Chang Young
CY
Hur
Won Don
WD
Lee
Jin Ho
JH
Lim
Apoptosis; Container; Embryos; Mice; Vitrification