Fig. 1.

Schematic diagram of the surgical operation and examination of the quality of First- and Second-oocytes. As a control, oocytes were collected after euthanasia as usual. Exp. 1: First-oocytes were collected via surgery under anesthesia, and their quality was examined by in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). Then, fertilized embryos were cultured up to 4 days, or on the next day, two-cell stage embryos were transferred into recipient females. Exp. 2: 10–30 days after surgical operation, Second-oocytes were collected by euthanasia, and their quality was examined as in Exp. 1. Exp. 3: 10–30 days after surgical operation, germinal vesicle (GV)-stage oocytes were collected from the ovaries and matured in vitro. Once these oocytes matured to the MII stage, they were used as in Exp. 1. Exp. 4: To prevent the adhesion of oviducts, the cutting position of the ampulla was changed, and the number of Second-oocytes was examined. Exp. 5: Reused mice were used as recipient mice at 10–30 days after surgical operation. Morulae/blastocysts were transferred into the uteri of pseudopregnant reused mice.