New technique for mouse oocyte injection via a modified holding pipette

Area of Science:

• Reproductive Biology
• Developmental Biology
• Assisted Reproductive Technologies

Background:

• Intracytoplasmic sperm injection (ICSI) is a key assisted reproductive technology.
• Improving oocyte survival rates post-ICSI is crucial for successful fertilization.
• Current methods sometimes involve modifications to the injection pipette, but holding pipette modifications offer an alternative approach.

Purpose of the Study:

• To enhance mouse oocyte survival rates following intracytoplasmic sperm injection (ICSI).
• To evaluate the efficacy of a novel holding pipette design with a trumpet-shaped opening for ICSI.
• To assess fertilization and survival rates using this modified holding pipette for both autologous and interspecies ICSI.

Main Methods:

• A modified holding pipette featuring a trumpet-shaped opening was designed and utilized.
• Mouse oocytes were injected with mouse spermatozoa (autologous ICSI) and human spermatozoa (interspecies ICSI) at 37°C.
• Oocyte survival and fertilization rates were compared between the modified holding pipette and a conventional holding pipette.

Main Results:

• The modified holding pipette resulted in a significantly higher mouse oocyte survival rate (83%) compared to the conventional pipette (21%) for autologous ICSI (P<0.001).
• Fertilization rates were comparable between the two methods for autologous ICSI (82% vs. 81%).
• For interspecies ICSI (mouse oocyte with human spermatozoon), the modified pipette yielded a superior survival rate (82%) and acceptable fertilization rate (71%).

Conclusions:

• A holding pipette with a trumpet-shaped opening offers a more convenient manipulation method for ICSI.
• This modified holding pipette design significantly improves mouse oocyte survival rates.
• The technique allows for acceptable mouse oocyte survival and fertilization rates using standard sharp injection pipettes, even for interspecies ICSI under typical human ICSI conditions.