A Nonsurgical Embryo Transfer Technique for Fresh and Cultured Blastocysts in Rats

Area of Science:

• Reproductive Biology
• Animal Science
• Laboratory Animal Science

Background:

• Surgical embryo transfer in rodents can cause pain and distress.
• Existing assisted reproductive techniques for rats lack a refined, nonsurgical embryo transfer method.
• Developing a nonsurgical approach is crucial for animal welfare and ethical research practices.

Purpose of the Study:

• To describe an efficient nonsurgical embryo transfer technique for rat blastocysts.
• To introduce the rat nonsurgical embryo transfer (rNSET) device for delivering fresh or cultured embryos.
• To validate the safety and efficacy of the rNSET technique in pseudopregnant female rats.

Main Methods:

• Development and utilization of the rat nonsurgical embryo transfer (rNSET) device, comprising a Teflon catheter and a pipette hub.
• Cervical dilation using oxytocin to facilitate catheter insertion into the uterine horn.
• Delivery of fresh or cultured blastocyst-stage embryos into the uterine horn of recipient rats.

Main Results:

• The rNSET technique achieved pup recovery rates comparable to traditional surgical embryo transfer.
• Nonsurgical embryo transfer did not induce significant stress in recipient rats, evidenced by stable weight and normal corticosterone levels.
• The procedure was performed effectively without the need for anesthesia or analgesia.

Conclusions:

• The developed rat nonsurgical embryo transfer (rNSET) technique is an efficient and refined method for rodent assisted reproduction.
• This nonsurgical approach minimizes animal distress and health complications associated with surgical procedures.
• The rNSET method provides a humane and effective alternative for rat embryo transfer in research settings.