USE OF CULTURED PERMANENT LINES OF INTESTINAL EPITHELIAL-CELLS FOR THE ASSAY OF OKADAIC ACID IN MUSSEL HOMOGENATES

Two non-transformed intestinal epithelial cell lines (RIE-1 and IEC-6) and three intestinal carcinoma cell lines (HT-29, T84 and MCA-38) wer e used to detect the toxic effects due to okadaic acid in the presence of mussel tissue homogenates. Cytotoxicity was assessed by measuremen t of the metabolic conversion of 3-[4,5-dimethylthiazol-2-yl]-2,5-diph eny tetrazolium bromide to its corresponding formazan dye. All of the cell lines were sensitive to okadaic acid, with HT-29, RIE-1 and IEC-6 showing the greatest response. Dilutions of whole mussel tissue homog enates caused some loss of viability in most of the cell lines but had no significant effect on the viability of RIE-1 cells. In no case did the mussel homogenate compromise the dose-response curve to okadaic a cid when data were normalized to the appropriate control value. These intestinal epithelial cell lines may prove useful in the bioassay of o kadaic acid and related toxins.