title: Vitrification solution without sucrose for cryopreservation in mouse blastocysts.
abstract: OBJECTIVE
  This study was designed to investigate the survival rate of vitrified mouse blastocysts depending on the presence or absence of sucrose in vitrification solution.
  
  
  METHODS
  Mouse two-cell embryos were collected and cultured to blastocysts. Two vitrification solutions were prepared. The control solution was composed of 25% glycerol, 25% ethylene glycol, and 0.5 M sucrose (G25E250.5S) containing 2.5 mL glycerol, 2.5 mL ethylene glycol, 2 mL SSS, and 0.855 g sucrose in 5 mL PB1. The experimental solution was composed of 25% glycerol and 25% ethylene glycol (G25E25) and contained 2.5 mL glycerol and 2.5 mL ethylene glycol in 5 mL PB1. Artificial shrinkage was conducted by aspirating the blastocoelic fluid using an ICSI pipette. To examine the effect of sucrose in the vitrification solution on the survival rate of mouse blastocysts, the shrunken-equilibrated blastocysts were rehydrated or vitrified after being exposed to one of the two vitrification solutions. After exposure and the vitrification-thawing process, the re-expansion rate and hatching rate were evaluated after 6 hours of in vitro culture.
  
  
  RESULTS
  The re-expansion rate of mouse blastocysts exposed to vitrification solution with and without sucrose were not different in the experimental solution (without sucrose) (98%) and the control solution (with sucrose) (92%) (p>0.05). The hatching rate was higher in the experimental solution (95%) than in the control solution (88%), but did not differ across two treatments (p>0.05). The re-expansion rate of mouse blastocysts vitrified in the control solution was 92% and 94%, respectively (p>0.05), and the hatching rate was higher in the experimental solution (90%) than in the control solution (74%) (p<0.05).
  
  
  CONCLUSIONS
  Sucrose need not be added in vitrification solution for freezing of artificially shrunken mouse blastocysts.
authors.affiliation: Department of Obstetrics and Gynecology, Pusan National University School of Medicine and Medical Research Institute, Pusan National University Hospital, Busan, Korea.
authors.forename: Jong Kil
authors.initials: JK
authors.lastname: Joo
authors.affiliation: Department of Obstetrics and Gynecology, Pusan National University School of Medicine and Medical Research Institute, Pusan National University Hospital, Busan, Korea.
authors.forename: Young Ju
authors.initials: YJ
authors.lastname: Lee
authors.affiliation: Department of Obstetrics and Gynecology, Pusan National University School of Medicine and Medical Research Institute, Pusan National University Hospital, Busan, Korea.
authors.forename: Ju Eun
authors.initials: JE
authors.lastname: Jeong
authors.affiliation: Department of Obstetrics and Gynecology, Pusan National University School of Medicine and Medical Research Institute, Pusan National University Hospital, Busan, Korea.
authors.forename: Seung Chul
authors.initials: SC
authors.lastname: Kim
authors.affiliation: Infertililty Center, Pusan National University Hospital, Busan, Korea.
authors.forename: Gyoung Rae
authors.initials: GR
authors.lastname: Ko
authors.affiliation: Department of Obstetrics and Gynecology, Pusan National University School of Medicine and Medical Research Institute, Pusan National University Hospital, Busan, Korea.
authors.forename: Kyu Sup
authors.initials: KS
authors.lastname: Lee
keywords: Artificial shrinkage; Blastocyst; Sucrose; Vitrification