In Vitro Cytotoxicity of the Organotin Compound Bis-(tri-n-butyltin)oxide to FG Cells.

The FG cell line derived from the gills of flounder paralichthys olivaceus was used to determine the acute cytotoxic effects of the organotin compound bis-(tri-n-butyltin)oxide (TBTO). Its cytotoxic effects were initially measured by three endpoint systems: neutral red (NR) uptake assay, tetrazolium (MTT) assay, and cell protein assay. Results indicated that the doses of TBTO ranging from 1.7 x 10(- 10) to 1.3 x 10(- 7) M were all toxic, and no difference in cytotoxicity was found between the three test systems. The transmission electron microscopic examination of TBTO-exposed cells revealed that their ultrastructures were markedly altered, as evidenced by dilation of mitochondria, breakdown of rough endoplasmic reticulum, nuclear membrane dissolution, and increased level of lysosomes. It is clear that the cells are highly susceptible to TBTO. This renders FG cells one of several choices for rapidly evaluating the acute toxicities of organotin compounds like TBTO. The mode of action of TBTO leading to the cytotoxicity, including the ultrastructural alteration in FG cells, is also proposed.