NF-κB activation and expression of cytokines in bladder cells after E. coli challenge. Bladder cells were stimulated with heat-killed E. coli for 24 h at a concentration corresponding to 108 cfu/ml. (A) Relative NF-κB activation was measured by luciferase activity (n = 4) and the protein levels of (B) TNF, (C) IL-6, and (D) CXCL8 were measured by ELISA (n = 3). Error bars represent the standard errors of the means. Bars labeled with an asterisk significantly differ from the control (p-values < 0.05).