The Use of Whole Embryo Culture in the Study of Teratogenic Mechanisms

Abstract

The techniques of whole embryo culture have been extensively used in the study of teratogenic mechanisms and are now being evaluated for possible applications in teratogen screening. The culture method may be used in several ways depending on the information required. 1. Direct exposure of the embryo to the teratogen. This will reveal the direct effect of an agent independent of any interaction with the maternal metabolism. 2. Addition of the agent with drug metabolising systems. This is a method of re-adding drug metabolism by incorporation of microsomes and co-factors or intact, isolated hepatocytes. It is analogous to the Ames test. 3. Serum from a treated or deficient individual as the culture medium. This procedure re-adds the effects of maternal metabolism and has greater similarity to in vivo exposure. Human serum can be used. 4. In vivo treatment with in vitro evaluation — pregnant rats are dosed with the teratogen. The embryos are subsequently explanted and cultured in serum from untreated individuals for evaluation. 5. Embryo culture as above followed by organ culture. The prolongation of development in vitro could permit repair of damaged tissue or reveal abnormalities which appear late in gestation.