Abstract:Objective To observe the effect of Shuangshen Ningxin capsule in alleviating myocardial ischemia/reperfusion injury in rats by regulating mitochondrial adenosine triphosphate（ATP）-sensitive potassium channels. Method A total of 56 adult male Sprague-Dawley rats were randomly divided into sham-operated control group (sham), model group (model), Shuangshen Ningxin group (SSNX, 90 mg·kg-1).Shuangshen Ningxin and mitochondrial ATP-sensitive potassium channel (MitoKATP) channel inhibitor group 5-hydroxyl-acid group (SSNX+5-HD, 5 mg·kg-1), with 14 rats in each group. Except the sham operation group, the other three groups received occlusion of left anterior descending coronary artery (LAD) for 45 min, and were sacrificed 3 h after reperfusion. Myocardial ischemia and infarct size were observed by TSC Evans blue staining, and myocardial tissue damage degree was observed by hematoxylin-eosin(HE) staining. The kit was used to measure serum lactate dehydrogenase (LDH), creatine kinase (CK) and creatine kinase isoenzyme (CK-MB). The ultrastructural changes of mitochondria and mitochondrial autophagy were observed under transmission electron microscope. The changes of mitochondrial membrane potential in cardiomyocytes were detected by fluorescent probe. Result Compared with the sham group, myocardial infarct size and myocardial ischemic area percentage in the model group were significantly increased, myocardial tissue arrangement was disordered and loose, individual myocardial fibers were broken, cardiomyocytes were necrotic, and serum CK, CK-MB, LDH activities were significantly increased (P<0.01). Mitochondrial membrane potential was significantly decreased (P<0.01), and mitochondrial structure was destroyed by transmission electron microscopy. Compared with the model group, the myocardial tissue of the SSNX group was arranged orderly, and a small amount of cell edema was mildly degenerated. The percentage of myocardial infarct size and myocardial ischemic area was significantly decreased, serum CK, CK-MB, and LDH activities were significantly decreased (P<0.01), while mitochondrial membrane potential increased (P<0.01). Compared with the model group, the SSNX+5-HD group had mild myocardial tissue disorder and mild degeneration of cell edema in some areas, the percentage of myocardial infarct size and myocardial ischemic area was significantly reduced, serum CK, CK-MB, and LDH activities were significantly decreased (P<0.01), and mitochondrial membrane potential increased (P<0.01). Compared with SSNX group, SSNX+5-HD group had significant increase in serum CK, CK-MB and LDH activities (P<0.01), significant increase in the percentage of myocardial infarct size and myocardial ischemic area, and mitochondrial membrane potential Reduced (P<0.05). Conclusion SSNX protects rat myocardial ischemia-reperfusion injury by opening mitochondrial ATP-sensitive potassium channel.
