The effect of DG on calcium accumulation induced by a H/R-challenge in H9c2 cells. A) calcium signal was measured at 0, 5, 10 and 15 min by a confocal microscope after Fluo-4 AM staining; B) Quantitative, real-time measurement of calcium accumulation. KB-R 7943 was a Na+-Ca2+ exchanger antagonist, which was used as a positive control. The calcium signal was normalized to that at 0 min in each group. The data were expressed as mean ± S.E.M. Three independent experiments were performed. ***p < 0.001 indicated the groups with significant difference when compared to the control group.