Generation of Cynomolgus Monkeys (Macaca fascicularis) Embryos with ICSI Based on the MII-Stage Oocytes Acquired by Personalized Superovulation Protocol

ABSTRACT The use of cynomolgus monkeys ( Macaca fascicularis ) has facilitated the establishment of gene-modified animal models, and the appropriate number of high-quality mature oocytes (MII-stage oocytes) are crucial in assisted reproductive technologies (ART) of cynomolgus macaques. In this study we performed 3 different superovulation protocols on 24 female cynomolgus monkeys aimed to improve the proportion of MII-stage oocyte retrieval. The results suggested some differences in the proportion of MII-stage oocytes between the personalized superovulation protocol and the superovulation protocols I and II. Afterwards, we performed Intracytoplasmic sperm injection (ICSI) on 22 MII-stage oocytes derived from one animal with personalized superovulation protocol, obtained 15 embryos of 2-4-cells, 2 cases of successful pregnancy after transferring to 4 surrogate female, and obtained 3 aborted fetuses. These results suggested that personalized superovulation protocol incorporated the menstrual cycle length of each cynomolgus monkey, and the timing of oocytes retrieval based on the equation: menstrual cycle length/2 ± 1, which increased the rate of MII-stage oocytes acquired and generation of cynomolgus monkeys embryos with ICSI based on these oocytes, and finally could successfully develop into fetus under conditions that effectively guarantee the synchronization of the surrogate mothers. SUMMARY STATEMENT The personalized superovulation protocol based on the menstrual cycle length of each cynomolgus monkey can increase the rate of MII-stage oocytes acquired, and finally could successfully develop into fetus under conditions that minimize damage to the surrogate mothers and effectively guarantee the synchronization of the surrogate mothers.