LASER-ASSISTED MICRODISSECTION OF THE ZONA-PELLUCIDA FACILITATES POLAR BODY BIOPSY

Objective: To investigate whether polar body biopsy can be performed a fter laser microdissection of the zona pellucida (ZP). Design: Mouse z ygotes were allocated randomly to three groups. The zygotes were subje cted to laser microdissection of the ZP and polar body biopsy (group 1 ), laser microdissection alone (group 2), or no treatment (group 3). S etting: University-based IVF program. Patient(s): Animal study. Interv ention(s): A hole was drilled in the ZP of mouse zygotes using a 1.48- mu m noncontact diode laser. A microneedle was inserted and the polar body was aspirated. Main Outcome Measure(s): The efficacy of polar bod y biopsy after laser microdissection of the ZP was evaluated. Result(s ): The laser diode beam allowed for precise drilling of a 14- to 18-mu m hole in the ZP. Polar bodies could be aspirated without damaging th e zygote and did not disintegrate during the biopsy. Zygotes developed to blastocysts and underwent the same hatching as control zygotes. Lo wer hatching rates were observed in untreated zygotes. Conclusion(s): Laser microdissection of the ZP with a noncontact laser system facilit ates subsequent polar body biopsy. The use of blunt-ended micropipette s greatly reduces the risk of damage to the zygote or the polar body. This procedure makes polar body biopsy more accurate and effective for preimplantation genetic diagnosis. (C) 1998 by American Society for R eproductive Medicine.