Generation of cynomolgus monkey fetuses with intracytoplasmic sperm injection based on the MII-stage oocytes acquired by personalized superovulation protocol

BACKGROUND: Mature oocytes at the metaphase II status (MII-stage oocytes) played an important role in assisted reproductive technology in non-human primates. OBJECTIVES: In order to improve the proportion of MII-stage oocytes retrieval, three different superovulation protocols were performed on 24 female cynomolgus monkeys. METHODS: All the monkeys received once-daily injection of follicle-stimulating hormone (25 international unit [IU]) on day 3 of the menstruation, 3-day intervals, twice daily for 8–12 days until the time of human chorionic gonadotropin (1,500 IU) injection, on the 14–17th day of menstruation collecting oocytes. The difference between protocol I and protocol II was that 0.1 mg the gonadotropin-releasing hormone agonist was injected on day 1 of the menstruation, while the difference between personalized superovulation protocol and protocol II was that oocytes could be collected on the 14–17th day of menstrual cycle according to the length of each monkey. RESULTS: The total number of oocytes harvested using the personalized superovulation protocol was much higher than that using protocol I (p < 0.05), and the proportion of MII-stage oocytes was significantly greater than that from either superovulation protocol I or II (p < 0.001 and p < 0.01 respectively), while the proportion of immature oocytes at the germinal vesicle was less than that from superovulation protocol I (p < 0.05). CONCLUSIONS: The personalized superovulation protocol could increase the rate of MII-stage oocytes acquired, and successfully develop into embryos after intracytoplasmic sperm injection, and eventually generated fetus.