title: Effect of Culture System on Developmental Competence, Cryosurvival and DNA-Fragmentation of In Vitro Bovine Blastocysts.
abstract: BACKGROUND
  This study investigated the effect of two in vitro embryo culture systems (co-culture system versus cell-free sequential-media) on developmental competence, cryosurvival and DNA- fragmentation of in vitro developed bovine blastocysts.
  
  
  METHODS
  Bovine presumptive zygotes were cultured in Ménézo's B2 (B2) plus vero-cells or sequential synthetic oviductal fluid (SOF) for eight days. Subsequently, half of the expanded blastocysts developed in both groups were vitrified, warmed within 30 minutes and post- warming embryos along with their corresponding non-vitrified embryos were cultured for two additional days in the same medium used before vitrification. Embryo development, cryosurvival and apoptosis were compared between the groups.
  
  
  RESULTS
  For non-vitrified embryos, culture in SOF significantly promoted the potency of embryos to develop into blastocysts compared with the co-culture system. The difference in post vitrification survival rate of SOF blastocysts (83.3%) was insignificant compared with co-culture (84.3%). However, while total cell number of warmed blastocysts in the co-culture system was significantly higher in the co-culture versus the sequential system (215.4 vs. 170.4), the quality of survived embryos in terms of hatching ability and apoptosis was adversely affected by co-culture compared with SOF (65.0% vs. 74.3%, and 13.5% vs. 10.0%, respectively; p<0.05).
  
  
  CONCLUSIONS
  Although co-culture system may increase the viability of embryos following cryopreservation, the potency and dynamics of blastocyst formation significantly increased with sequential media compared to the co-culture system which can compensate for the lower efficiency of sequential media for vitrification/warming purposes.
authors.affiliation: Reproduction and Development Department, Reproductive Biomedicine Center, Royan Institute for Animal Biotechnology, ACECR, Isfahan, Iran.
authors.forename: Mahdi
authors.initials: M
authors.lastname: Hajian
authors.affiliation: Reproduction and Development Department, Reproductive Biomedicine Center, Royan Institute for Animal Biotechnology, ACECR, Isfahan, Iran.
authors.forename: Seyed Morteza
authors.initials: SM
authors.lastname: Hosseini
authors.affiliation: Reproduction and Development Department, Reproductive Biomedicine Center, Royan Institute for Animal Biotechnology, ACECR, Isfahan, Iran.
authors.forename: Vajiheh
authors.initials: V
authors.lastname: Asgari
authors.affiliation: Reproduction and Development Department, Reproductive Biomedicine Center, Royan Institute for Animal Biotechnology, ACECR, Isfahan, Iran.
authors.forename: Somayyeh
authors.initials: S
authors.lastname: Ostadhoosseini
authors.affiliation: Reproduction and Development Department, Reproductive Biomedicine Center, Royan Institute for Animal Biotechnology, ACECR, Isfahan, Iran ; Animal Sciences Department, Islamic Azad University, Marvdasht Branch, Marvdasht, Iran.
authors.forename: Mohsen
authors.initials: M
authors.lastname: Forouzanfar
authors.affiliation: Reproduction and Development Department, Reproductive Biomedicine Center, Royan Institute for Animal Biotechnology, ACECR, Isfahan, Iran ; Embryology Department, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iran.
authors.forename: Mohammad Hossein
authors.initials: MH
authors.lastname: Nasr Esfahani
keywords: Blastocyst; Co-Culture; Cryoperservation; Embryo Development; Vitrification