Figure 1.
(A) To examine the dose-dependent effect of tumor necrosis factor α (TNFα) on IPEC-J2 cells, increasing concentrations were added basolateral to the monolayers and transepithelial electrical resistance (TEER) was measured for 48 h. Concentrations of 1000 U/mL and 5000 U/mL revealed a decrease in TEER in IPEC-J2 cells (one-way ANOVA, * p < 0.05, *** p < 0.001; n = 14–22). Therefore, following experiments were carried out using 1000 U/mL. (B) No significant changes in TEER could be observed after 24 h with 1000 U/mL TNFα. (C) Flux measurements using [3H]-D-Mannitol revealed an increased paracellular flux after 24 as well as 48 h (unpaired t-test, ** p < 0.01, n = 6). Resistance values are expressed as percentage of initial resistance and compared to controls, respectively. For analysis of paracellular flux, controls were set to 100% and values were compared to this, respectively. All data shown are presented as means ± SEM.