ATLA::Alternatives to Laboratory Animals

Volume 27, Number 6

Gastrulating Rat Embryo in a Serum-free Culture Model: Changes of Development Caused by Teratogen 5-Azacytidine.

ATLA 27, 925-933, November/December 1999

Floriana Bulic-Jakus,¹ Maja Vlahovic,¹ Godana Juric-Lekic,² Vesna Crnek-Kunstelj¹ and Drasko Serman¹

¹Strategic Toxicological Sciences and ²Statistical Services, GlaxoWellcome Research and Development, Ware, Hertfordshire SG12 ODP, UK

SUMMARY

Developmental processes in gastrulating rat embryos were investigated by using an original, serum-free, chemically defined model system. 9.5-day-old rat embryos, without extraembryonic membranes, were cultivated at the air-liquid interface in a serum-free medium with and without a protein supplement, for 2 weeks. A teratogenic, demethylating agent, 5-azacytidine, was added to serum-free and protein-free culture medium and to serum-free medium supplemented with human transferrin. A single dose of 5-azacytidine impaired the survival growth and differentiation of embryos in protein-free medium and serum-free medium with transferrin. In contrast, repeated exposure to 5-azacytidine was required to impair growth in serum-supplemented medium. It was concluded that the activity of 5-azacytidine was easier to detect in a simple, chemically defined medium than in a serum-supplemented medium. This serum-free in vitro method could be useful in screening for teratogenic or embryotoxic substances during gastrulation, the most critical stage of mammalian development.

Keywords: rat embryo, serum-free, 5-azacytidine, teratogen, transferrin