title: Effect of cryotop vitrification on preimplantation developmental competence of murine morula and blastocyst stage embryos.
abstract: Vitrification is an effective method for the cryopreservation of mammalian embryos. Nevertheless, it is unclear which embryonic developmental stage is the most suited for vitrification and would ensure maximal developmental competence upon subsequent warming. This study, therefore, compared the effects of cryotop vitrification on the developmental competence of murine morula and blastocyst stage embryos. Additionally, trophectoderm (TE) and inner cell mass (ICM) cell numbers were compared in two hatched blastocyst groups derived from vitrified morulae and blastocysts, respectively. The post-vitrification survival rates for mouse embryos at the morula and blastocyst stage were 95.4% (186/195) and 96.5% (195/202), respectively. The blastocyst formation rate was significantly lower for vitrified morulae (90.3%) compared with the non-vitrified control group (98.4%) (P < 0.05). The hatching rates were similar between the vitrified morula (79.6%) and the vitrified blastocyst (81.0%) groups. When further development to the fully hatched blastocyst stage was compared, fully hatched blastocysts derived from vitrified morulae had significantly higher cell counts for both the ICM and TE lineage, as compared with hatched blastocysts derived from vitrified blastocysts (P < 0.001). Cryotop vitrification of mouse embryos at the morula stage rather than blastocyst stage would thus ensure a higher degree of post-warming developmental competence.
authors.affiliation: Department of Reproduction, Nanjing Maternity and Child Health Hospital, Nanjing Medical University, Nanjing, PR China.
authors.forename: Xiu Feng
authors.initials: XF
authors.lastname: Ling
authors.forename: Jun Qiang
authors.initials: JQ
authors.lastname: Zhang
authors.forename: Shan Ren
authors.initials: SR
authors.lastname: Cao
authors.forename: Jie
authors.initials: J
authors.lastname: Chen
authors.forename: Yuzhu
authors.initials: Y
authors.lastname: Peng
authors.forename: Xirong
authors.initials: X
authors.lastname: Guo
authors.forename: Boon Chin
authors.initials: BC
authors.lastname: Heng
authors.forename: Guo Qing
authors.initials: GQ
authors.lastname: Tong
authors.forename: Xinru
authors.initials: X
authors.lastname: Wang
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000166:cytology*; D015925:Cryopreservation; D046149:Embryo Culture Techniques; D047108:Embryonic Development / Q000502:physiology*; D005260:Female; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009028:Morula / Q000166:cytology*