Cytotoxic activity of fumonisin B₁ in Vero cells: comparison between 2D and 3D structural microplates

The present study aimed to estimate cytotoxic activity of fumonisin B₁ (FB₁) in Vero cells using crystal violet staining assay (CVA) and lactate dehydrogenase assay (LDH) performed in flattened (2D) and three dimensional (3D) bottom (V, U, and M) microplates. Vero cells were exposed to different concentrations of FB₁ ranging from 0 to 10 μg/ml for 24 and 48 h. Tween 20 was used as a positive control and acetonitrile 50% in water was used as a negative control. Results revealed that CVA could be performed in the F type microplate for 24 and 48 h but it was useless in the 3D microplates. LDH assay showed that FB₁ induced significant cytotoxicity on Vero cells after 24 h exposure in all microplates. Using 3D bottom microplates allowed formation of spheroid cell aggregates and reduced cell adhesion. LDH release in the U type microplate showed a significant dose-dependent increase, while V type and M type microplates showed a significant dose-independent increase in all exposed cells. Forty-eight hours exposure to FB₁ in 2D microplate induced time-related cytotoxicity in all exposed cells pronounced as increased percentage of dead cells and significant increase in LDH release at 0.01, 0.1, 1, and 10 μg/ml. It was concluded that 2D culture plate is suitable for both LDH and CVA while 3D microplates are suitable only for the LDH assay. LDH assay could detect the cytotoxic effect of FB₁ at lower concentrations than crystal violet staining assay.