FIG. 8.

Flux measurement with Lucifer yellow. Confluent monolayers of IEC-6 cells were grown on Millicell-HA filters and incubated for 24 h with live parasites, live parasites after pretreatment of cells with the broad-spectrum caspase inhibitor Z-VAD-fmk, or live parasites along with the antiprotozoal drug metronidazole. Monolayers incubated with only growth medium served as a negative control. Permeability was determined by measurement of Lucifer yellow fluxes across the monolayer as described in Materials and Methods. A significant increase in the epithelial permeability can be noticed after incubation with live parasites and parasitic lysate in comparison to the control monolayer. Pretreatment of IEC-6 cells with caspase inhibitors does not considerably rescue these cells from Blastocystis-induced effect on permeability, but exposure of Blastocystis to metronidazole abolished the effect significantly. Values are means ± standard deviations (error bars) (three monolayers per group). Values that were significantly different from the values for live-parasite-treated samples are indicated (*, P = 0.2; **, P < 0.05).