title: The effect of various assisted hatching techniques on the mouse early embryo development.
abstract: OBJECTIVE
  In search of an ideal method of assisted hatching (AH), we compared the effects of conventional micropipette-AH and laser-AH on the blastocyst formation rate (BFR) and blastocyst cell numbers.
  
  
  METHODS
  Four- to five-week-old ICR female mice were paired with male mice after superovulation using Pregnant mare's serum gonadotropin (PMSG) and hCG. The two-cell embryos were flushed from the oviducts of female mice. The retrieved two-cell embryos underwent one of five AH procedures: single mechanical assisted hatching (sMAH); cross mechanical assisted hatching (cMAH); single laser assisted hatching (sLAH); quarter laser assisted hatching (qLAH); and quarter laser zona thinning assisted hatching (qLZT-AH). After 72 hours incubation, double immunofluorescence staining was performed.
  
  
  RESULTS
  Following a 72 hours incubation, a higher hatching BFR was observed in the control, sMAH, cMAH, and sLAH groups, compared to those in the qLAH and qLZT-AH groups (p<0.05). The hatched BFR was significantly higher in the qLAH and qLZT-AH groups than in the others (p<0.05 for each group). The inner cell mass (ICM) was higher in the control and sMAH group (p<0.05). The trophectoderm cell number was higher in the cMAH and qLAH groups (p<0.05).
  
  
  CONCLUSIONS
  Our results showed that the hatched BFR was higher in groups exposed the the qLAH and qLZT-AH methods compared to groups exposed to other AH methods. In the qLAH group, although the total cell number was significantly higher than in controls, the ICM ratio was significantly lower in than controls.
authors.affiliation: Fertility Clinic, Mirae Ladies Hospital, Daejeon, Korea.
authors.forename: Sung Baek
authors.initials: SB
authors.lastname: Park
authors.affiliation: Department of Obstetrics and Gynecology, Chungnam National Hospital, Daejeon, Korea.
authors.forename: Hye Jin
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Fertility Clinic, Mirae Ladies Hospital, Daejeon, Korea.
authors.forename: Young Bae
authors.initials: YB
authors.lastname: Choi
authors.affiliation: Fertility Clinic, Mirae Ladies Hospital, Daejeon, Korea.
authors.forename: Kwang Hwa
authors.initials: KH
authors.lastname: Ahn
authors.affiliation: Department of Obstetrics and Gynecology, Chungnam National Hospital, Daejeon, Korea.
authors.forename: Kee Hwan
authors.initials: KH
authors.lastname: Lee
authors.affiliation: Department of Obstetrics and Gynecology, Chungnam National Hospital, Daejeon, Korea.
authors.forename: Jung Bo
authors.initials: JB
authors.lastname: Yang
authors.affiliation: Department of Animal Resources, Daegu University, Gyeongsan, Korea.
authors.forename: Chang Seok
authors.initials: CS
authors.lastname: Yu
authors.affiliation: Department of Animal Resources, Daegu University, Gyeongsan, Korea.
authors.forename: Byoung Boo
authors.initials: BB
authors.lastname: Seo
keywords: Assisted hatching; Cell number; Laser assisted hatching; Mechanical assisted hatching; Mouse embryo