A controlled ovarian stimulation procedure suitable for cynomolgus macaques

Area of Science:

• Reproductive Biology
• Primate Research
• Assisted Reproductive Technologies

Background:

• Optimizing ovarian stimulation protocols is crucial for non-human primate research.
• Cynomolgus macaques are widely used models, necessitating efficient reproductive procedures.
• Previous methods using gonadotropin-releasing hormone agonists (GnRH-a) may impose significant physiological stress.

Purpose of the Study:

• To evaluate and compare the efficacy of gonadotropin-releasing hormone antagonist (GnRH-ant) versus GnRH-a based ovarian stimulation protocols in cynomolgus macaques.
• To assess the impact of the stimulation protocol on oocyte yield, fertilization rates, and animal well-being.
• To determine the optimal protocol for controlled ovarian stimulation in this species.

Main Methods:

• Cynomolgus macaques were divided into four groups based on stimulation protocol (GnRH-a or GnRH-ant) and prior menstruation frequency (≤7 or ≥8 times/year).
• Ovarian stimulation involved human follicle-stimulating hormone and human chorionic gonadotropin administration.
• Oocyte maturation, fertilization rates, zygote yield, and body weight changes were analyzed.

Main Results:

• The GnRH-ant groups (7AN and 8AN) showed higher fertilization rates (85.3% and 74.7%) compared to GnRH-a groups (59.1% and 47.3%).
• The 8AN group produced the highest number of zygotes (19.9 per macaque).
• Macaques receiving GnRH-ant experienced significantly smaller body weight decreases, indicating reduced physiological burden.

Conclusions:

• Controlled ovarian stimulation using GnRH-ant is more advantageous for cynomolgus macaques than GnRH-a.
• GnRH-ant protocols lead to improved fertilization rates and zygote yield.
• GnRH-ant administration reduces the physiological stress associated with ovarian stimulation in macaques.