Teratogenic effect of a diphenylhydantoin on the neurulation of the explanted early chick embryos were studied using the punched-out filter paper explantation technique. The 6th to 9th Hamburger and Hamilton staged chick embryos were explanted
and
cultured in the Ham's F-10 media treated with 15㎍/ml, 30㎍/ml, 60㎍/ml, 90㎍/ml, 120㎍/ml of diphenylhydantoin in the CO2 incubator for 6-9hours. The morphological characteristics and the ultrastructural changes of the neuroepithelium of early
chick
embryos were compared with the control and experimental group using the stereomicroscope and the electron microscope. Of the 40 chick embryos cultured in the Ham's F-10 media without dr㎍, 37 embryos (92.5%) developed normally and 3 embryos
(7.5%)
developed abnormally. The 153 embryos cultured in the diphenylhydantoin-treated media were developed abnormally in 94 embryos (61.4%) The frequent anomalous features of the embryos were deformities of the neural folds in the cranial regions,
failure of
neural tube closure, dispersion of somites and developmental arrest. The scanning electron microscopic findings of neuroepithelial cells of abnormally developed embryos were diminished surface blebs and microvilli, flattened and smooth cellular
surfaces, and irregular size of cells. The transmission electron microscopic findings of neuroepithelial cells of abnormally developed embryos showed not significant changes of the development of intracellular organelles except the smooth
cellular
surfaces and mild underdevelopment of microfilaments.
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