p38 MAP kinase and tumor necrosis factor-α (TNF-α) are important regulators that mediate stretch-induced TLR4 expression in cardiomyocytes. (A) Representative Western blots for TLR4 protein levels in cardiomyocytes subjected to cyclic stretch for 6 h or control cells without stretch in the absence or presence of different inhibitors, and siRNA. CM indicates conditioned medium. (B) Quantitative analysis of TLR4 protein levels. The values from stretched cardiomyocytes have been normalized to values in control cells (n = 4 per group). *P < 0.001 vs. stretch 6 h. **P < 0.01 vs. stretch 6 h. +P < 0.001 vs. control.