Cardiovascular diseases such as myocardial ischaemia have a high fatality rate in patients with diabetes. This study was designed to expose the crosstalk between oxidative stress and AMPK, a vital molecule that controls
biological energy metabolism, in myocardial ischaemia
reperfusion injury (I/RI) in diabetic rats. Diabetes was stimulated in rats using
streptozotocin injection. Rats were separated on random into control, control + I/R, Diabetes, Diabetes + I/R, Diabetes + I/R + N-
acetylcysteine and Diabetes + I/R + Vas2870 groups.
Myocardial infarct size was determined, and the predominant Nox family
isoforms were analysed. In vitro, the H9C2 cells were administered excess
glucose and exposed to
hypoxia/reoxygenation to mimic diabetes and I/R. The AMPK
siRNA or
AICAR was used to inhibit or activate AMPK expression in H9C2 cells, respectively. Then, myocardial oxidative stress and programmed cell death were measured. Diabetes or high
glucose levels were found to aggravate myocardial I/RI or
hypoxia/reoxygenation in H9C2 cells, as demonstrated by an increase in
myocardial infarct size or
lactate dehydrogenase levels, oxidative stress generation and induction of programmed cell death. In diabetic rat hearts, cardiac Nox1, Nox2 and Nox4 were all heightened. The suppression of Nox2 expression using
Vas2870 or Nox2-siRNA treatment in vivo or in vitro, respectively, protected diabetic rats from myocardial I/RI. AMPK gene knockout increased
Nox2 protein expression while AMPK agonist decreased Nox2 expression. Therefore, diabetes aggravates myocardial I/RI by generating of Nox2-associated oxidative stress in an AMPK-dependent manner, which led to the induction of programmed cell death such as apoptosis, pyroptosis and ferroptosis.