Optimised CO2-containing medium for in vitro culture and transportation of mouse preimplantation embryos without CO2 incubator

PLoS One. 2021 Dec 23;16(12):e0260645. doi: 10.1371/journal.pone.0260645. eCollection 2021.

Abstract

Conventional in vitro culture and manipulation of mouse embryos require a CO2 incubator, which not only increases the cost of performing experiments but also hampers the transport of embryos to the other laboratories. In this study, we established and tested a new CO2 incubator-free embryo culture system and transported embryos using this system. Using an Anaero pouch, which is a CO2 gas-generating agent, to increase the CO2 partial pressure of CZB medium to 4%-5%, 2-cell embryos were cultured to the blastocyst stage in a sealed tube without a CO2 incubator at 37°C. Further, the developmental rate to blastocyst and full-term development after embryo transfer were comparable with those of usual culture method using a CO2 incubator (blastocyst rate: 97% versus 95%, respectively; offspring rate: 30% versus 35%, respectively). Furthermore, using a thermal bottle, embryos were reliably cultured using this system for up to 2 days at room temperature, and live offspring were obtained from embryos transported in this simple and very low-cost manner without reducing the offspring rate (thermal bottle: 26.2% versus CO2 incubator: 34.3%). This study demonstrates that CO2 incubators are not essential for embryo culture and transportation and that this system provides a useful, low-cost alternative for mouse embryo culture and manipulation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blastocyst / physiology*
  • Carbon Dioxide / administration & dosage*
  • Culture Media
  • Culture Techniques / methods
  • Embryo Culture Techniques / methods*
  • Embryo Transfer / methods*
  • Embryo, Mammalian / cytology*
  • Embryo, Mammalian / physiology
  • Female
  • Fertilization in Vitro
  • Incubators / statistics & numerical data
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Inbred ICR

Substances

  • Culture Media
  • Carbon Dioxide

Grants and funding

This work was partially funded by the Japan Society for the Promotion of Science to M.O. (17K15394), to D.I. (JP20J23364); the Naito Foundation to S.W.; Takahashi Industrial and Economic Research Foundation to S.W. (189); Asada Science Foundation to T.W.; Takeda Science Foundation to T.W.: and Canon Foundation for Scientific Research to T.W. (M20-0006).