Ovarian stimulation, in vitro fertilization, and effects of culture conditions on baboon preimplantation embryo development

Objective: To evaluate the effects of ovarian stimulation and intracytoplasmic sperm injection (ICSI)-induced fertilization and efficacy of various culture systems on in vitro development of baboon embryos. Design: In vitro study, animal model. Setting: Research laboratory. Animal(s): Baboons in laboratory animal research facility. Intervention(s): Baboons received FSH (75 IU daily) for 7 to 8 days and FSH/LH (75/75 IU daily) for 3 days, followed by hCG (2,000 IU). Oocytes were retrieved laparoscopically 36 hours after hCG. Intracytoplasmic sperm injection was performed on metaphase II (MII) oocytes. Fertilized embryos were placed into different culture conditions and feeder cell coculture. Embryo development was observed through the most advanced stages, including blastocyst formation. Main Outcome Measure(s): Oocytes retrieved, fertilization rates, multicell embryo rates, and blastocyst rates. Result(s): Baboon oocytes (n = 1,924, from 49 cycles) were retrieved. Significant heterogeneity was seen in ovarian response to exogenous gonadotropins and subsequent oocyte maturation. The percentage of MII oocytes showed no significant difference among individual female baboons and stimulation cycles. Nearly two thirds of MII oocytes were successfully fertilized with ICSI. Blastocyst rates varied significantly among embryos in different treatments. Coculture with feeder cells in P1/Blast, Quinn's Advantage, and Sydney IVF media generated better blastocyst rates. Conclusion(s): We tested multiple media and feeder cell combinations to optimize culture conditions in baboon embryo culture and obtained a high blastocyst rate similar to those reported for rhesus monkey embryos cultured in vitro, but still lower than with assisted reproductive technologies in women.