Repeated surgical oocyte collection from severe immunodeficient NOG mice after repeated superovulation with inhibin antiserum and eCG

Repeated surgical oocyte collection in mice enables the harvest of multiple cohorts of eggs from a single female, thereby reducing the need for animal use. Traditionally, oocyte collection for the mouse requires euthanasia, and only two sequential collections have been reported. The most efficient superovulation protocol involves the use of inhibin antiserum; however, repeated administration may pose a risk of anaphylactic reactions. In this study, we used severely immunodeficient NOG mice to evaluate the feasibility of performing three serial oocyte collections with inhibin antiserum treatments. We found that three consecutive cycles of antiserum administration followed by surgical retrieval cycles were achieved without mortality. Although the number of mice from which oocytes could be collected decreased over successive cycles, oocyte retrieval remained feasible. The application of the anti-adhesion film improved the number of mice from which oocytes could be recovered. Furthermore, embryos derived from the third retrieval developed to term after transfer. However, compared with the control group, we were unable to achieve a proportional increase in the number of retrieved oocytes corresponding to the number of collection cycles. Further improvements to this repeated collection method may include increasing the number of consecutive retrievals, optimizing the protocol to enhance both the oocytes yield and the fertilization rates. Such advances could increase oocyte yield per female, enable the mass production of embryos from fewer animals.