Protective effect of Xinning tablet on acute myocardial ischemia in anesthesia dogs

This work aimed to observe the protective effect of Xinning tablets on experimental myocardial ischemia. The canine model of acute myocardial infarction was established by ligating the anterior descending coronary artery of dogs. The ultrasound Doppler method was adopted to determine myocardial blood flow. Heart membrane electrical diagram coup and nitro blue tetrazolium (N-BT) staining were used to calculate the extent of myocardial ischemia and myocardial infarct size. Radioimmunoassay was used to determine plasma ET, TXB₂ and 6-Keto-PGF_1α levels. 30-180 min after administration of Xinning tablets at 1.2 and 0.6 g/kg, the dog myocardial ischemia icon measured from the epicardial electrogram was significantly reduced; the infarct area was decreased according to NBT staining. 30-120 min after the administration, cardiac blood flow was significantly increased in the myocardial ischemia area, the levels of plasma ET and TXB₂ were greatly inhibited, and the 6-Keto-PGF1α content to TXB₂/6-Keto-PGF1α ratio was increased. Taken together, Xinning tablets have significant protective effect on dog acute myocardial ischemia and myocardial infarction, the mechanism of which may be related to ET inhibition, TXA₂ release and increased myocardial blood flow, consequently improving the impaired heart function.