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Use of zona drilling for safe and effective biopsy of murine oocytes and embryos
1Brookdale Center for Molecular Biology, Mt. Sinai Medical Center, New York, New York 10029.
Abstract:
With the mouse as a model, we have used zona drilling to devise procedures for safe removal of the first polar body or one or more blastomeres from cleaving embryos. These methods require minimal disruption of the zona pellucida and little or no direct contact between microtools and the materials to be biopsied. Of 175 eggs subjected to the polar body biopsy procedure, 1 was killed, and 165/174 survivors were fertilized (94.8%). For blastomere biopsy, embryos from the 2- to 16-cell stage were incubated in a chelating medium containing 100 mM sucrose for at least 30 min. The zonae were then drilled, and one or more blastomeres were "pushed" out through the hole by pressure exerted against the zona at some distance from the drilling site. In all 85 embryos biopsied, one or more additional intact blastomeres were successfully removed. Moreover, 83/84 biposied embryos that were subsequently cultured developed into blastocysts (98.8%). Although acid Tyrode's solution was used in this study, mechanical methods of zona opening were also effective. The data indicate that oocyte and embryo biopsy assisted by zona drilling is safe and does not appear to affect fertilization or development, and as such, it is applicable to genetic diagnostic procedures.
Insights
Zona drilling enables safe oocyte and embryo biopsy in mice, facilitating polar body or blastomere removal without impacting fertilization or development. This technique is suitable for genetic diagnostics.
Area of Science:
- Reproductive Biology
- Developmental Biology
- Assisted Reproductive Technologies
Background:
- Oocyte and embryo biopsy are crucial for preimplantation genetic diagnostics.
- Minimally invasive techniques are needed to ensure safety and viability.
Purpose of the Study:
- To develop and evaluate safe and effective methods for oocyte and embryo biopsy using zona drilling.
- To assess the impact of zona drilling-assisted biopsy on fertilization and embryonic development.
Main Methods:
- Zona drilling was employed to create small openings in the zona pellucida of mouse oocytes and embryos.
- Polar bodies and blastomeres were removed through these openings with minimal manipulation.
- Embryos were cultured to assess developmental potential post-biopsy.
Main Results:
- Polar body biopsy resulted in a high fertilization rate (94.8%) among survivors.
- Blastomere biopsy from 2- to 16-cell stage embryos yielded intact blastocysts in 98.8% of cases.
- Both acid Tyrode's solution and mechanical methods for zona opening proved effective.
Conclusions:
- Zona drilling is a safe and effective assisted reproductive technology for oocyte and embryo biopsy.
- The procedure does not adversely affect fertilization or subsequent embryonic development.
- This technique is applicable for genetic diagnostic purposes.