Use of Drosophila embryo cell cultures as an in vitro teratogen assay.

An in vitro assay has been developed for detecting teratogens by adding them to primary cultures of embryonic Drosophila cells and analyzing the degree of change in cell differentiation and tissue formation. Cultures are scored by an automated image analysis system that counts the number of myotubes and ganglia in culture. A decrease in their number compared to controls is taken as an indication of teratogenicity. In the group of 100 drugs and chemicals examined thus far in this assay, a high correlation with known teratogenic activity has been obtained with few false-positives or false-negatives. Procedures also have been developed for testing metabolic products of ingested compounds for teratogenicity. Mice and rats are fed the particular agent to be tested, and their serum is then added to the differentiating culture. Preliminary trials with human serum from patients receiving chemotherapy have also been performed. With further testing, validation, and incorporation of a metabolic activation system, it is hoped that this assay can be used, along with a battery of other in vitro assays, as a screen for the large number of agents awaiting comprehensive testing of their teratogenic potential. We also see the use of this assay as means to gain further information on the basic biochemical and developmental aspects of teratogenesis.