Toxic effects of tributyltin on early zebrafish embryos
2002
Muramoto, W. (Rakuno Gakuen Univ., Ebetsu, Hokkaido (Japan)) | Shirato, R. | Kumagai, Y. | Teraoka, H. | Hiraga, T.
Tributyltin (TBT) is one of the most extensive marine pollutants, because it has been widely used as a pesticide and antifouling paint for a long time. Recent findings of severe endocrine disruptive actions of TBT, especially in mollusks, had had a great impact. It has been reported that TBT has developmental toxicity as well as neurotoxicity and immunotoxicity in mice. However, little is known about the effects of TBT on development of fish, despite their importance for the fishery industry. In the present study, we investigated the effects of waterborne TBT on early-stage embryos of zebrafish (Danio rerio). High concentrations of TBT (92-154 nM) caused mortality from 24 to 120 hours post fertilization (hpf). Mortality was not observed at 120 hpf in embryos that had been exposed to TBT of less than 31 nM. TBT caused concentration-dependent edema around the heart, yolk and eyes after 84 hpf. Degeneration of the tip of the tail fin bud by TBT was detected by acridine orange staining, and this was followed by fin fold atrophy and curvature of the tail. TBT severely retarded growth of upper jaw and lower jaw primordia without having any remarkable effect on total body length. This effect might not arise from migration failure of neural crest cells, because TBT exerted the same effect by later application. TBT reduced blood flow in the trunk but did not affect the head region, including the region around jaw, suggesting that TBT has direct effects on jaw primordia. These results suggest that zebrafish embryos are an useful model for study of the mechanisms of developmental toxicolosrv by TBT.
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