Optimization and Application of Mouse Embryo Transfer Technology

doi:10.12300/j.issn.1674-5817.2026.069

Abstract

Abstract:

Objective To optimize the technical parameters of mouse embryo transfer (including oviduct opening method, pseudopregnant recipient body weight, number of embryos transferred per recipient, and unilateral vs. bilateral oviduct transfer), improve the efficiency of embryo transfer (the pregnancy rate of recipient female mice after embryo transfer is used as the evaluation index), and improve the utilization rate of high-quality embryo germplasm resources (the birth rate of mice after embryo transfer is used as the evaluation index). Methods 560 SPF-grade ICR mice and 440 C57BL/6J mice were used as experimental animals. 2-cell embryos were obtained through in vitro fertilization. A single-factor controlled variable method was used to systematically investigate the effects of four factors, including oviduct opening method, pseudopregnant recipient body weight, number of embryos transferred per recipient, and unilateral vs. bilateral oviduct transfer, on the pregnancy rate and birth rate of mouse embryo transfer. Results The pregnancy rate of recipients with an opening made in the oviduct using a 26G syringe needle reached 90%, which was significantly higher than the 43% in the group with oviduct openings cut by Vannas scissors (P<0.05). Pseudopregnant recipients weighing 29-35 g exhibited optimal embryo transfer outcomes, with a pregnancy rate of 90% and a birth rate of 44%, and no pups were crushed by the recipient mothers. The highest birth rate of 42% was observed in the group receiving 16-25 embryos per recipient. Transferring 26-35 embryos per recipient achieved a 90% pregnancy rate and maximized embryo utilization efficiency. However, transfer efficiency decreased significantly when more than 35 embryos were transferred. Transfer of 24-26 embryos per recipient balanced relatively high pregnancy and birth rates. Bilateral oviduct transfer of mouse embryos yielded slightly higher pregnancy and birth rates than unilateral transfer, but the difference was not statistically significant (P>0.05). Conclusion Selecting pseudopregnant recipient female mice weighing 29-35 g, using a 26G syringe needle to make an opening in the oviduct, and controlling the number of transferred embryos at 24-26 per recipient can effectively improve the success rate of embryo transfer and achieve efficient utilization of high-quality embryo germplasm resources.

Key words: Embryo transfer, In vitro fertilization, Technical optimization, Transfer efficiency, ICR mice, C57BL/6J mice

CLC Number:

ZHANG Jiaoling,LIN Aping,XU Shiying,et al. Optimization and Application of Mouse Embryo Transfer Technology[J]. Laboratory Animal and Comparative Medicine, 2026, 46(5): 750-758. DOI: 10.12300/j.issn.1674-5817.2026.069.

Figures/Tables 4

Figure 1 Effects of two oviduct opening methods （Vannas scissors cutting <i>vs</i>. 26G needle puncture） on pregnancy rate and pup birth rate of pseudopregnant ICR mice during embryo transfer

Note： A， Schematic diagram of making an opening in the oviduct using Vannas scissors； B， Schematic diagram of making an opening in the oviduct using a 26G syringe needle； C， Statistical results of pregnancy rate in recipient mice with two oviduct opening methods； D， Statistical results of pup birth rate after embryo transfer with two oviduct opening methods. ^*** P<0.001.

Figure 2 Effects of different body weight ranges of pseudo-pregnant ICR recipients on pregnancy rate， pup birth rate， and 7-day pup survival rate following embryo transfer

Note： A， Comparison of pregnancy rate in recipient mice among different body weight groups； B， Comparison of pup birth rate among different body weight groups； C， Comparison of 7-day pup survival rate among different body weight groups. ^* P<0.05， ^** P<0.01， ^*** P<0.001， ^**** P<0.000 1.

Figure 3 Effects of the number of 2-cell embryos transferred per recipient in a single transfer on pregnancy rate and pup birth rate in pseudopregnant ICR mice

Note： A， Pregnancy rates in recipients transplanted with embryos at gradient doses of 5-15， 16-25， 26-35， and 36-45 embryos； B， Pup birth rates in the same four groups； C and D， Pregnancy and pup birth rates， respectively， in recipients grouped by finer embryo-number intervals with the range of 16-35 embryos. ^ns P>0.05， ^** P<0.01， ^*** P<0.001， ^**** P<0.000 1.

Figure 4 Effects of unilateral and bilateral oviduct embryo transfer on pregnancy rate and pup birth rate in pseudopregnant ICR mice

Note： A， Pregnancy rate of recipient mice subjected to unilateral or bilateral oviduct embryo transfer； B， Pup birth rate after unilateral or bilateral oviduct embryo transfer. ^ns P>0.05.

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