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Updated: Dec 19, 2025
Retrieval of Mouse Oocytes
Published on: April 28, 2007
Improvement of a twice collection method of mouse oocytes by surgical operation
Rei Inoue1, Kana Harada1, Sayaka Wakayama2
1Faculty of Life and Environmental Science, University of Yamanashi, Yamanashi 400-8510, Japan.
Abstract:
Mouse oocytes are generally collected after euthanasia. However, if oocytes were collected without euthanasia, then mice could be used to collect oocytes again after recovery. This condition is especially useful for mice that are genotypically rare. In this study, we examined the reusability of mice after collecting oocytes via a surgical operation. When oocytes were collected using medetomidine/midazolam/butorphanol combination anesthesia and examined for the quality of oocytes after in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI), they could develop to full term at the same rate as controls. When oocytes were collected from those mice a second time, the average number of oocytes was reduced by nearly 1/3. However, the blastocyst and offspring rates of those oocytes after IVF or ICSI were the same as those of the control regardless of the recovery day period. Although germinal vesicle (GV) oocytes can be collected from all reused mice, the final number of offspring did not increase. Interestingly, when oocytes were collected from the front position of the ampulla, 76% of the oviducts possessed oocytes after reuse, and the average number of oocytes significantly increased to a level comparable to that of the control. Finally, we examined whether reused mice can be used as recipient females, and then healthy offspring were obtained similarly as the control recipients. In conclusion, we provide a new method to collect a sufficient number of oocytes from reused mice without concern.
Insights
Mice can be reused for oocyte collection after surgical recovery, yielding viable embryos and offspring. Reusing mice offers a valuable method for preserving genetically rare mouse lines without compromising reproductive outcomes.
Area of Science:
- Reproductive Biology
- Animal Models
- Oocyte Collection
Background:
- Traditional mouse oocyte collection often involves euthanasia.
- Genetically rare mouse lines require preservation and efficient reproductive strategies.
- Non-lethal oocyte retrieval methods are needed to maximize the utility of valuable mouse models.
Purpose of the Study:
- To evaluate the feasibility and efficacy of reusing mice for oocyte collection after a surgical procedure.
- To assess the developmental potential and offspring rates of oocytes obtained from reused mice.
- To determine if reused mice can serve as effective recipients for embryo transfer.
Main Methods:
- Surgical oocyte collection from mice under medetomidine/midazolam/butorphanol anesthesia.
- In vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) of collected oocytes.
- Assessment of oocyte quality, blastocyst formation, and offspring rates.
- Evaluation of reused mice as embryo recipients.
Main Results:
- Oocytes from reused mice supported normal embryonic development and full-term offspring rates after IVF/ICSI.
- Second oocyte collection yielded approximately one-third fewer oocytes, but blastocyst and offspring rates remained comparable to controls.
- Collection from the anterior ampulla significantly increased oocyte yield in reused mice.
- Reused mice functioned effectively as recipient females, producing healthy offspring.
Conclusions:
- Mouse reuse for oocyte collection is a viable strategy, particularly for rare genetic lines.
- Surgical oocyte retrieval and subsequent reuse do not compromise oocyte developmental potential or offspring viability.
- Optimizing collection sites within the oviduct can enhance oocyte yield from reused mice.
- This method provides a humane and efficient approach to maximize the reproductive output from valuable mouse models.
