Figure 8. Exogenous H2S restores PC-induced cardioprotection by up-regulating the HB-EGF/EGFR pathway, which activates the ERK1/2-c-myc (and fos and c-jun) and PI3K-Akt-GSK-3β pathways in the aged cardiomyocytes. Endogenous H2S is decreased and then leads to loss of the protective role of PC in the aged cardiomyocytes. Supplementation of exogenous H2S up-regulates the HB-EGF/EGFR pathway, which activates the ERK1/2-c-myc (and fos and c-jun) and PI3K-Akt-GSK-3β pathways, which inhibits apoptosis via down-regulating the mitochondrial apoptosis pathway (Cyt c-caspase-3) by decreasing the release of Cyt-c and the expression of caspase-3, and -9 and increasing the expression of Bcl-2. Finally, PC-induced cardioprotection is restored.