Figure 1. Exogenous H2S increases the expression and content of HB-EGF and the level of phosphorylated EGFR in the aged H9C2 cells. (A) The content of HB-EGF was measured using an HB-EGF ELISA kit. The HB-EGF content in the control group was considered the basal levels, and the HB-EGF content of the others was detected as the fold change from the control group. All data are the means ± S.E.M. of 8 determinations. (B) The activity of phosphorylated EGFR and the expression of HB-EGF. The graphs represent the optical density of the bands of phosphor-EGFR (p-EGFR) normalized to the expression of total-EGFR (t-EGFR). The graphs represent the optical density of the bands of HB-EGF normalized to the expression of the GAPDH signal. All data were from three independent experiments. * p<0.05 vs. control group; # p<0.05 vs. H/R group; & p<0.05 vs. PC group; § p<0.05 vs. H/R + NaHS group; $ p<0.05 vs. PC + NaHS group.