Objective   Cell lines were empolyed to explore the possibility of taking permanent cell lines as models for detecting microcystins and studying their mechanism of cytotoxicity.

  Methods   Eight kinds of cell strains from different hosts (KB, NIH/3T3, H-4-II-E, Hela, Vero, HepG2, Caco-2, HL-60 cell)were mixed with purified microcystin-LR and incubated for 24, 48, 72 and 96 hours; Meanwhile morphological alterations, colorimetric 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide(MTT)assays, lactate dehydrogenase(LDH)release assay were respectively used to evaluate the end point of toxicity.

  Results   Among 8 cell lines, KB and H-4-II-E cell lines showed significant dose-response effect at toxin concentrations greater than 18.8μg/ml with 96-hour incubation.In KB cells the toxin induced marked morphological alterations after incubation for 8 hours which was with good reproducibility and consistency.LDH assay results showed that microcystin-LR caused cell membrane damage.

  Conclusion   Purified microcystin-LR did induce toxic effect on KB and H-4-II-E cell lines.However, considering morphological changes, reproducibility and consistency, KB cells seemed to be a better potential model for evaluating cytotoxicity of microcystin-LR.