A simple method of culture of 11.5-day-old rat embryos in DMEM/F12 and 20% fetal bovine serum

Post-implantation mouse and rat embryos are usually cultured in sera obtained from various rodents and from humans. We describe here a simple and inexpensive culture medium - Dulbecco's minimal essential medium/Ham's F12 (DMEM/F12) supplemented with 20% fetal bovine serum (FBS) - in which E11.5 rat embryos of the Hebrew University Sabra strain grow for 28 h slightly better than in heat-inactivated 90% rat serum with 10% distilled water and addition of 1 mg mL^-1 glucose. They have good growth and development and a low rate of anomalies, similar to that observed in embryos cultured on rat serum. Their size, total score and olfactory system development is slightly higher than in rat embryos cultured in rat serum. About 7.2% of these embryos exhibit subcutaneous haemorrhages in various areas, but these do not seem to interfere with their growth and development. This method is not appropriate for younger embryos; in E10.5 embryos cultured for 28 h we found increased embryonic death and anomalies.