Figure 4.

Flux measurement with FITC-conjugated Dextran. Confluent monolayers of Caco-2 cells were coincubated for 24 h with Blastocystis ST-4 or ST-7. Some monolayers were coincubated with ST-7 after pretreatment of cells with the broad-spectrum caspase inhibitor Z-VAD-fmk. Permeability was determined by measurement of Dextran-FITC fluxes across the monolayer as described in Section 2. A significant increase in the epithelial permeability can be noticed after incubation with ST-7, compared to negative control and ST-4 coincubation (P value < 0.01). Pretreatment of Caco-2 cells with caspase inhibitor significantly rescued these cells from Blastocystis-induced effect on permeability. Cytochalasin D (Cyt-D) was used as a positive control in inducing permeability increase. Values are means ± standard error (error bars) (n = 6).