title: Laser-assisted hatching of cleavage-stage embryos impairs developmental potential and increases DNA damage in blastocysts.
abstract: This study aims to investigate the influence of two- (day 2) and six-to-eight-cell-stage (day 3) laser-assisted hatchings on the developmental potential and genetic integrity of the embryos. In this prospective experimental study, two- and six-to-eight-cell-stage mouse embryos were subjected to laser hatching using 1,480 nm diode laser, and then assessed for the developmental potential and DNA integrity in blastocysts. Similarly, four-cell-stage human embryos from 20 patients were also subjected to laser hatching, and then assessed for the developmental competence. Laser-assisted hatching in mouse embryos significantly enhanced the blastocyst hatching potential on day 4.5 (P < 0.0001). However, a significant decline in blastocyst total cell number (TCN) was observed in six-to-eight-cell-stage laser-hatched embryos (P < 0.001). Conversely, no significant difference in TCN was observed between laser-hatched and unhatched human four-cell-stage embryos after 24 h. Attempt to understand the genetic integrity in laser-hatched mouse blastocysts revealed significantly higher labeling index when hatching was done at two- (P < 0.01) and six-to-eight-cell stage (P < 0.05). DNA damage induced by the laser manipulation may affect implantation and postimplantation developmental potential of the embryos. However, further studies are required to elucidate the impact of laser-induced DNA damage on the reproductive outcome.
authors.affiliation: Division of Clinical Embryology, Department of Obstetrics and Gynecology, Kasturba Medical College, Manipal University, Manipal, 576 104, India.
authors.forename: Sachin D
authors.initials: SD
authors.lastname: Honguntikar
authors.forename: Shubhashree
authors.initials: S
authors.lastname: Uppangala
authors.forename: Sujith R
authors.initials: SR
authors.lastname: Salian
authors.forename: Guruprasad
authors.initials: G
authors.lastname: Kalthur
authors.forename: Pratap
authors.initials: P
authors.lastname: Kumar
authors.forename: Satish K
authors.initials: SK
authors.lastname: Adiga
mesh_terms: D000368:Aged; D000818:Animals; D001755:Blastocyst / Q000502:physiology / Q000528:radiation effects*; D002452:Cell Count; D004249:DNA Damage; D046149:Embryo Culture Techniques; D047108:Embryonic Development / Q000528:radiation effects; D006801:Humans; D054023:Lasers, Semiconductor; D053844:Lasers, Solid-State; D051379:Mice