[Studies on the pharmacological bases of fetal toxicity of drugs. (VI) Teratogenic effects of trypan blue and related compounds in rats].

The teratogenicity of trypan blue and its related compounds was studied in Wistar rats and the following results were obtained: 1) o-Tolidine, 1-amino-8-naphthol-3, 6-disulfonic acid or 1-nitronaphthalene-3, 6-disulfonic acid was injected subcutaneously on day 7 of pregnancy (sperm = day 0). No fetotoxicity was observed in any group. 2) The main fractions, blue fraction (blue fr.) and red fraction (red fr.), were separated from commercial trypan blue (C-TB) by silica gel column chromatography. C-TB, blue fr. or red fr. was injected into pregnant rats subcutaneously on day 7 of pregnancy. The incidence of malformed fetuses after injection of blue fr. was higher than that of C-TB, and the types of malformations induced by C-TB and blue fr. were similar. However, no fetotoxicity was detected after injection of red fr. 3) Blue fr. or red fr. was injected into the exocoelom on day 11 of pregnancy. The incidence of malformed fetuses in the group injected with blue fr. (2.5 micrograms/embryo) was 39%, and the types of malformations were abnormal tail and vertebrae, which were also observed after injection of C-TB or blue fr. into pregnant rats. No significant teratogenic effect was observed after injection of red fr. From these data, it was concluded that the teratogenic effect of C-TB might be due to the blue fr., but not the red fr.