Fig. 4. Inhibition of NHE-1 prevents ERS-induced apoptosis. (A) Effect of pretreatment with NHE-1 specific inhibitor, cariporide, on cardiomyocyte apoptosis. Twenty micromolar of cariporide was added 30 minutes before TM (100 ng/ml) treatment. After 48 h, cardiomyocytes were subjected to TUNEL assay. Apoptotic cells represented by the TUNEL-positive cells (magenta in the merged images) were counted. Nuclei were identified by staining with Hoechst 33342 (blue). (B) Quantification of the percentage of TUNEL-positive cells. (C) NRVMs were treated with cariporide (20 μM) 30 minutes before TM (100 ng/ml) treatment for 24 h. Western blotting was performed using an antibody against CHOP. α-tubulin is shown as a loading control (Left). The quantitative analysis of the western blotting results is presented (Right). All data represent mean ± SEM; N = 3; Statistical significance is shown as *P ＜ 0.05 or **P ＜ 0.001. Data were statistically analyzed by one-way ANOVA followed by a Bonferroni’s multiple-comparison of multiple means.