title: Development of a method of vitrification, thawing, and transfer of mammalian blastocysts using a single closed cryo-straw.
abstract: BACKGROUND
  There are different methods for cryopreservation of mammalian embryos with variable degrees of success. These methods require specific vessels for embryo vitrification, thawing, and transfer.
  
  
  OBJECTIVE
  Here, we report a simple and inexpensive way to vitrify, thaw and transfer mammalian blastocysts in one straw.
  
  
  METHODS
  This in-straw vitrification solution with microdrop (ISVDM) was compared with EM grid and normal 0.25 mL straw methods.
  
  
  RESULTS
  There were no differences in the rates of re-expanded and hatching-to-hatched murine and bovine blastocysts exposed to 1, 0.5, and 0.3 M of sucrose in the diluent that was loaded into the straw. Low re-expanded and hatching-to-hatched rates of murine and bovine blastocysts were observed with PBS only. The pregnancy rates of control murine blastocysts (57.1%) and blastocysts exposed to 0.3 M sucrose in diluent and ISVDM (71.4%) were significantly higher (p < 0.05) than those exposed to 1, 0.5, and 0 M sucrose and those loaded into 0.25 mL straws. The rate of offspring delivery was highest in the control group. There was no significant difference (p < 0.05) in the rate of offspring delivery among ISVDM, 0.25 mL straw, and EM grid groups.
  
  
  CONCLUSIONS
  Our results indicate that vitrified embryos can be warmed and diluted in a single straw and that this one-step method enables farm animal embryo transfer without a microscope or other laboratory equipment.
authors.affiliation: Department of Animal Sciences, Chungbuk National University, Cheongju, South Korea.
authors.forename: Young Tae
authors.initials: YT
authors.lastname: Heo
authors.affiliation: Min Byung Yul Infertility Hospital, Cheongju, South Korea.
authors.forename: Joon Kyo
authors.initials: JK
authors.lastname: Lim
authors.affiliation: Department of Animal Sciences, Chungbuk National University, Cheongju, South Korea.
authors.forename: Yong Nan
authors.initials: YN
authors.lastname: Xu
authors.affiliation: Department of Animal Sciences, Chungbuk National University, Cheongju, South Korea.
authors.forename: Woo
authors.initials: W
authors.lastname: in Jang
authors.forename: Soon Hong
authors.initials: SH
authors.lastname: Jeon
authors.affiliation: Department of Animal Sciences, Chungbuk National University, Cheongju, South Korea. nhkim@chungbuk.ac.kr.
authors.forename: Nam-Hyung
authors.initials: NH
authors.lastname: Kim
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D002417:Cattle; D015925:Cryopreservation; D003451:Cryoprotective Agents / Q000494:pharmacology; D004624:Embryo Transfer / Q000295:instrumentation / Q000379:methods / Q000662:veterinary*; D005260:Female; D005307:Fertilization in Vitro / Q000295:instrumentation / Q000379:methods*; D051379:Mice; D008813:Mice, Inbred ICR; D011247:Pregnancy; D018873:Pregnancy Rate; D013395:Sucrose / Q000494:pharmacology; D058989:Vitrification
chemical_list: D003451:Cryoprotective Agents; D013395:Sucrose