Preconditioning the rat heart with 5-azacytidine attenuates myocardial ischemia/reperfusion injury via PI3K/GSK3β and mitochondrial K signaling axis.

5-Azacytidine is well known for its clinical usage in cancer treatments. The present study investigates the role of 5-azacytidine as a cardioprotective agent to ameliorate ischemia/reperfusion (I/R) injury. The cardioprotective effect of 5-azacytidine was evaluated in three experimental models: in vitro, ex vivo, and in vivo. The cardioprotective effect was evaluated via cell viability, hemodynamic indices, infarct size measurement, and assessment of histopathology, oxidative stress, and mitochondrial function. The experiments were repeated in the presence of PI3K/GSK3β and mitochondrial K (mtK ) cardioprotective signaling pathway inhibitors to understand the underlying mechanism. 5-Azacytidine improved the cell viability by 29% in I/R-challenged H9C2 cells. Both isolated rat heart and LAD ligation model confirmed the infarct sparing effect of 5-azacytidine against I/R. It also provided a beneficial effect by normalizing the altered hemodynamics, reducing the infarct size and cardiac injury markers, reversing the perturbation of mitochondria, reduced oxidative stress, and improved the pPI3K and pAKT protein expression from I/R. In addition, it also augmented the activation of PI3K/AKT and mtK signaling pathway, confirmed by using wortmannin (PI3K inhibitor), SB216763 (GSK3β inhibitor), and glibenclamide (mtK channel closer). The effectiveness of 5-azacytidine as a cardioprotective agent is attributed to its activation of the PI3K/GSK3β and mtK channel signaling axis, thereby preserving mitochondrial function and reducing oxidative stress.