| Objective:To compare the applied value of phosphorus-31 magnetic resonance spectroscopy (31P-MRS) and high performance liquid chromatography (HPLC) in canine with stunned myocardium; To conduct a dynamic survey on relationship among the energy metabolism, the changing regularity of the potential of hydrogen (pH) and the change of myocardial ultrastructure in stunned myocardium; To investigate the occurrence mechanism and the process of outcome; To create dynamic abservational survey method of local change on the energy metabolism of myocardium. Thus we provide noninvasive diagnostic method for clinical evaluation of the myocardial energy metabolism, immediate myocardium protection therapy, prognosis and follow-up. Methods:18 canine of 14~17 Kilogram were chosen as the object of experiments. The chest was opened under anaesthesia, an animal model of stunned myocardium was established by reperfusing the left anterior descending branch (LAD) of coronary artery after its occlusion for 15 minutes. The change of high-energy-6-phosphates compound was observed at 15 minutes after myocardial ischemia and 2h, 6hx 2dx 3d after reperfusion by HPLC. The change of 31P-MRS was also observed on the same site at the same time so as to have a comparison. The absolute value of energy metabolism of myocardium \vas gained by basic physical chemistry methods to investigate the relationship between the change of energy metabolism according to 31P-MRS of stunned myocardium and the change of energy metabolism by HPLC. Thus the survival condition of myocardium can be determined. The change of cell and tissue under myocardial ischemia and reperfusion was also observed through light microscope and electron microscope to investigate relationship of local energy metabolism and tissue change between 31P-MRS and HPLC observation.Results:1. HPLC results in canine with stunned myocardium show that the content of PCr obviously decreased, and the content of ATP also decreased, but still maintained in the relatively higher level (P<0.05) 15 minutes after myocardial ischemia. At the same time, the content of ADP and AMP increased, while total adenine nucleotides and energy charge decreased markly (PO.05). The content of PC^ ATP, TAN and EC increased respectively(P<0.05), while the content of ADP and AMP decreased (P<0.05) 2 hours after reperfusion. PCr turned to normal limits 6 hours after reperfusion. and has no obvious change after this time point, while ATP, TAN and EC increased more gradually than PCr and still didn't return to normal limits until 3 days after reperfusion (p<0.05).2.31P-MRS results show that PCr, P -ATP, PCr/ P -ATP and the pH decreased (PO.05), but Pi, Pi/PCr and Pi/P -ATP ratio increased (PO.05) 2 hours after reperfusion on the case of acute myocardial ischemia for 15 minutes. PCr and Pi/PCr turned to normal level 6 hours after reperfusion, and they have no obvious changes after this time point. PCr/P -ATP and the pH increased (PO.05) 6 hours after reperfusion, while Pi and Pi/ P -ATP ratio decreased, and gradually turned to normal level until 3 days after reperfusion.-7-3. The results of synchronous observation of J|P-MRS and HPLC on the same site of myocardium at corresponding time shows that two methods have good correlation, and no significant differentce (P>0.05). Both of the two methods shows that PCr> ATP and PCr/ATP ratio all decreased 2 hours after reperfusion, while PCr/ATP ratio increased to the peak 6 hours after reperfusion, and was still higher than the normal level 3 days after reperfusion. The content of PCr turned to and exceeded normal level 6 hours after reperfusion, while the content of ATP still could not return to normal level until 3 days after reperfusion.4.The changes of stunned myocardium through light microscope show swollen myofibrils, unclear striate and light staining, after reperfusion, striate can be visible. The changes through electron microscope show markedly swollen myofibrils, unclear striate, light chromosome margination, edema cardiac muscle cell, swollen...
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