FIGURE 4.

IL-13-induced barrier regulation does not require epithelial apoptosis. A, apoptosis was assessed by cleaved caspase 3 detection. Even at high doses (light gray bars; 1 ng/ml for 24 h), IL-13 did not induce epithelial apoptosis. Z-VAD (all hatched bars; 50 μm) reduced apoptosis in control and IL-13-treated T84 monolayers to the same degree. B and C, neither TER nor PNa⁺/PCl⁻ were affected by Z-VAD (all hatched bars) after high dose IL-13 treatment (gray bars). Results were similar with lower IL-13 doses (0.1 ng/ml, not shown) (***, p ≤ 0.001, S.E.).