title: Opening of the mouse zona pellucida by laser without a micromanipulator.
abstract: A contact-free laser system is described for ablation of the embryonic mouse zona pellucida using a pulsed excimer 308 nm laser. Effects on further embryonic development were evaluated. Zonae of 8- to 16-cell mouse embryos were either lased (n = 189), zona-drilled with acidified Tyrode's solution (n = 183) or left zona-intact (n = 188). Blastocyst formation (99-100%) was similar in the three groups. Hatching occurred earlier in lased embryos compared to those of the control group. These blastocysts hatched through the laser ablated area. Significantly more embryos were hatching on day 4 in the conventionally drilled group when compared to the laser treated group (50% versus 24% respectively). On day 7 of development, significantly (P < 0.05) more embryos conventionally zona-drilled (37%) were intact than those which were previously laser treated (10%). Abnormal development was also noted in a small group of embryos which were lased just on the outside of the zona in comparison to 1/3 of an embryonic width away from the zona. The current results suggest that apparently precise zona laser ablation with an excimer laser at 308 nm may have potential adverse effects which may only be manifested after a prolonged period of culture past the cavitation stage. However, implantation rates of morphologically normal laser abalated embryos were not impaired when compared to control embryos.
authors.affiliation: Beckman Laser Institute, University of California, Irvine 92715.
authors.forename: J
authors.initials: J
authors.lastname: Neev
authors.forename: A
authors.initials: A
authors.lastname: Gonzalez
authors.forename: F
authors.initials: F
authors.lastname: Licciardi
authors.forename: M
authors.initials: M
authors.lastname: Alikani
authors.forename: Y
authors.initials: Y
authors.lastname: Tadir
authors.forename: M
authors.initials: M
authors.lastname: Berns
authors.forename: J
authors.initials: J
authors.lastname: Cohen
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000528:radiation effects; D046508:Culture Techniques; D010064:Embryo Implantation / Q000528:radiation effects; D005314:Embryonic and Fetal Development / Q000528:radiation effects; D005260:Female; D053685:Laser Therapy / Q000379:methods*; D051379:Mice; D008815:Mice, Inbred Strains; D015044:Zona Pellucida