Abstract: Objective To investigate the role of Creatine phosphate in myocardial ischemia-reperfusion (I/R) injury of rat heart in vivo. Methods 24 male SD rats weighing 200g～250g, were randomly divided into a Sham group; a I/R group and a Creatine phosphate（CP）group. CP group used the intravenous administration of 4 mg/kg Creatine Phosphate Sodium before the reperfusion. TUNEL method was used to detect apoptosis of cardiomyocytes. The formation of autophagosomes was observed by transmission electron microscopy. Expression of LC3-II was measured by the Western blotting. Results Comparing with Sham group, I/R aggravates injury of mitochondria, and increase autophagic vacuoles (AVs) (P<0.01) and apoptosis of cardiomyocytes (P<0.01). However, CP group alleviates injury of mitochondria and reduce autophagic vacuoles (P<0.05) and apoptosis of cardiomyocytes (P<0.05) comparing to I/R group. LC3-II formation, an autophagy marker, was down-regulated in the CP group (P<0.01), which less increased than I/R-injured rats (P<0.05). Conclusion These results suggest that Creatine phosphate inhibits apoptosis and excessive autophagy to diminish the cell death induced by the myocardial I/R injury.

Key words: autophagy, Ischemia-reperfusion injury, Creatine phosphate, apoptosis