AMPK works upstream of Nox2 in diabetic hearts. A, The change in protein expression of AMPK during myocardial I/RI in Con and diabetic rats, with or without Vas2870 treatment; B, The change in protein expression of p‐AMPK during myocardial I/RI in Con and diabetic rats, with or without Vas2870 treatment; C, The change in protein expression of AMPK during H/R in NG and HG, with or without siRNA Nox2; D, The change in protein expression of p‐AMPK during H/R in NG and HG, with or without siRNA Nox2; E, The change in protein expression of p‐AMPK during H/R in NG and HG, with or without siRNA AMPK, or agonist AICAR. Myocardial ischaemia reperfusion(I/R) was achieved by 30 min ischaemia and 120 min reperfusion; in the HG group, H9C2 cells were subjected 30 mmol/L glucose treatment for 48 h, H/R was achieved by 6 h hypoxia exposure and 12 h reperfusion. Data are expressed as mean ± SEM of two independent experiments, each performed in triplicates. n = 6 per group. * P < 0.05, **P < 0.01