Figure 2.

Effects of BAPTA on digoxin- and caffeine-induced calcium release and increased PPARδ expression in HG-treated H9c2 cells. (A) The intracellular calcium ion concentrations in H9c2 cells exposed to digoxin at final concentrations of 0.001, 0.01, 0.1 and 1 µM compared that control cells not treated with digoxin and (B) the effects of the various treatments on the changes in intracellular calcium concentration, as detected by the fura-2 probe using a fluorescence spectrofluorometer. (C) Effect of BAPTA on the digoxin-induced PPARδ expression in the HG-treated cells. Cells were treated with 25 mmol·L⁻¹ BAPTA for 30 min before incubation with 1 µmol·L⁻¹ digoxin or 1 µmol·L⁻¹ caffeine for 30 min, and then harvested to measure PPARδ protein expression by Western blot analysis. The response to caffeine at a concentration sufficient to increase intracellular calcium was used as positive control. All values are expressed as mean ± SEM (n = 4 per group). *P < 0.05, **P < 0.01 and ***P < 0.001 as compared with the HG-treated cells. ##P < 0.01 and ###P < 0.001 as compared with the HG-treated cells incubated with digoxin or caffeine.