title: Effect of laser-assisted multi-point zona thinning on development and hatching of cleavage embryos in mice.
abstract: OBJECTIVE
  This study aimed to examine the effect of laser-assisted zona thinning (LAZT) at one or four-points on the blastocyst formation and hatching process in mice with respect to female age.
  
  
  METHODS
  Eight-cell or morula embryos collected from superovulated C57BL female mice with different ages (6-11 and 28-31 weeks) were treated with LAZT at one-point (LAZT1) or four-points (LAZT4). The zona pellucida was thinned to more than 70% of its initial thickness by making two holes of 15-20 µm.
  
  
  RESULTS
  In the young mice, LAZT resulted in a significant increase in early hatching and hatching rates compared to the control group (p<0.05). However, in the old mice, LAZT significantly increased blastocyst formation as well as early hatching and hatching compared to the controls (p<0.05). These effects were more remarkable in LAZT4 than in LAZT1 and in aged mice than in young ones.
  
  
  CONCLUSIONS
  These results show that multi-point LAZT leads to a significant improvement of blastocyst formation and hatching in mice compared to controls.
authors.affiliation: Department of Pediatric Cardiology, Dong-A University Hospital, Busan, Korea.
authors.forename: Young Seok
authors.initials: YS
authors.lastname: Lee
authors.affiliation: Research Center for Anti-Aging Technology Development, Pusan National University, Busan, Korea.
authors.forename: Min Jung
authors.initials: MJ
authors.lastname: Park
authors.affiliation: Department of Obstetrics and Gynecology, Good Moonhwa Hospital, Busan, Korea.
authors.forename: Sea Hee
authors.initials: SH
authors.lastname: Park
authors.affiliation: Department of Obstetrics and Gynecology, Good Moonhwa Hospital, Busan, Korea.
authors.forename: Ja Seong
authors.initials: JS
authors.lastname: Koo
authors.affiliation: Department of Obstetrics and Gynecology, Good Moonhwa Hospital, Busan, Korea.
authors.forename: Hwa Sook
authors.initials: HS
authors.lastname: Moon
authors.affiliation: Research Center for Anti-Aging Technology Development, Pusan National University, Busan, Korea.
authors.forename: Bo Sun
authors.initials: BS
authors.lastname: Joo
keywords: Blastocyst formation; Hatching; Laser-assisted zona thinning; Multipoint laser-assisted zona thinning