Fig. 4

Administration of NHE1 activators, instead of inhibitors, resists pathological cardiac damage in mice during MI with acute hyperglycemia. A Schematic diagram showing the strategy for administering vehicle (DMSO) and NHE1 inhibitor (cariporide, Cari) to the mice. B The ratios of heart weight to body weight (HW/BW) in DMSO and Cari mice post 7 days MI with acute hyperglycemia, n = 10 (DMSO) and n = 8 (Cari). C and D High-frequency ultrasound echocardiography (HFUS) at day 7 after MI with acute hyperglycemia and the quantification of left ventricular ejection fraction (LVEF), n = 10 (DMSO) and n = 8 (Cari). E–G Representative Masson's trichrome staining and quantification of cardiac fibrosis in total heart area and LV wall thickness in DMSO and Cari mice at day 7 post MI with acute hyperglycemia, n = 7 per group, scale bar, 1 mm. H Analysis of serum BNP levels between DMSO and Cari mice at day 7 post-MI with acute hyperglycemia, n = 5 (DMSO) and n = 7 (Cari). I The experimental scheme of high-throughput screening of the activators of NHE1. J Schematic diagram showing the strategy for administering vehicle (Saline, 0.9% NaCl), LA and 3% NaCl to the mice. K Comparison of EF at baseline and day 7 post MI with acute hyperglycemia in Saline and 3% NaCl mice, n = 5 (Saline) and n = 8 (3% NaCl). L–N Representative Masson’s trichrome staining and quantification of cardiac fibrosis in total heart section area and LV wall thickness in Saline (n = 7), LA (n = 5) and 3% NaCl (n = 6) mice at day 7 post MI with acute hyperglycemia, scale bar, 1 mm. O Serum sodium concentrations from the Sham (n = 7), Saline (n = 7) and 3% NaCl (n = 6) post 7 day MI with acute hyperglycemia. P Correlation of serum sodium concentrations with EF post 7 day of MI with acute hyperglycemia (n = 13). Q Schematic diagram showing the strategy for I/R, Glu + I/R + vehicle (Saline) and Glu + I/R + 3% NaCl (3% NaCl) administration to the mice during I/R. R and S Representative Masson’s trichrome staining and quantification of cardiac fibrosis in Saline and 3% NaCl mice at day 7 post-reperfusion following 30 min of ischemia, with or without 15 min of acute hyperglycemia, n = 5 per group, scale bar, 1 mm. T and U Analysis of serum BNP levels and serum sodium concentrations from the Saline and 3% NaCl groups post 7 days reperfusion with acute hyperglycemia, n = 4 per group. Statistical significance in B, D, F, G, H and T, U were determined by two-tailed unpaired student’s t-test, while in K, M, N, O and S were determined by one-way ANOVA with Tukey’s test. The correlation in P was analyzed by Pearson's correlation coefficient and simple linear regression analyses. All quantitative data are expressed as mean ± SD. NS, not significant