| Background and aimIn recent years, the prevention and cure of the myocardial ischemia reperfusion injury (IRI), which have been widely used as the subsequent treatment method to the acute coronary artery spasm and heart intervention operation, attract more and more attention in clinic. Energy metabolism disturbance is the important mechanism of occurrence of myocardial IRI. Glycolysis, one of the fundamental energy sources in cardiac muscles, encourages the generation of adenosine triphosphate (ATP) during ischemia and the relief of IRI. Its content is directly related to the degree of myocardial injury. The increase of glucose uptake in ischemia myocardium is accomplished by the translocation of glucose transporters(GLUT), GLUT1 and GLUT4 from the cytosol to the membrane. Recent studies show that Qidan Tongmai Tablet (QDTMT) plays an important part in raising the activity of Ca2+-ATPase,Mg2+-ATPase,Ca2+-Mg2+-ATPase, inhibiting the Ca2+ inflow, degrading the amount of Ca2+ in the myocardial cells and mitochondria, lightening the calcium overload, increasing the activity of superoxide dismutase (SOD),glutathione peroxidase (GSH-Px) in myocardial mitochondria, and decreasing the content of malondialdehyde ( MDA ) in mitochondria. And thus QDTMT could effectively inhibit the destruction of oxygen free radical(OFR), reduce the size of myocardial infarction induced by ischemia and ischemia reperfusion, elevate the power of anti-oxidation and improve the function of the heart. To further investigate the mechanism that QDTMT protect the myocardial IRI, myocardial IRI model in rats was established with the coronary artery ligation, and the effects of QDTMT on expression of GLUT1, GLUT4 and glycogen in rats with myocardial IRI were studied.Methods1. The establishment of animal model 36 healthy male SD rats were randomly divided into 6 groups, 6 rats per group: control group, sham operation group, model group, QDTMT high dosage group(3.24 g/kg), QDTMT low dosage group(0.36 g/kg), Diltiazem Hydrochloride group(5 mg/kg). All rats were respectively administered with the same volume saline or drug liquid by gastrogavage once per day for 7days, and myocardial IRI model was established through the coronary artery ligation method after the last gastrogavage was given for 40 minutes on the 7th day. The coronary arteries of rats in model group and drug groups were performed ligation 40 minutes and reperfusion 4 hours. The coronary arteries in sham operation group were threaded but not ligated.2. Collection and treatment of tissue samples When the experiment was over, tissues in the reperfused region was sampled immediately, some fixed for glycogen staining, some preserved at -70℃for western blotting and the remaining for immunofluorescence.3. Periodic acid-schiff (PAS) method was applied to determine the glycogen amount in myocardial cells. The samples were observed under light microscope after fixation, embedment and section. The protein levels of GLUT1 and GLUT4 were determined by immunofluorescence and Western bolt.Results1. PAS staining is weak in model group, suggesting that the content of glycogen in myocardial cells were obviously decreased. PAS staining is strong in QDTMT high dosage group , QDTMT low dosage group and Diltiazem Hydrochloride group, suggesting that the content of glycogen were partly reduced. PAS staining is much stronger in control group and sham operation group, suggesting that the content of glycogen were not notably changed.2. Compared with control group, the expression of GLUT1 and GLUT4 increased in the model group, QDTMT high dosage group, QDTMT low dosage group and Diltiazem Hydrochloride group(P<0.05), while having no change in sham operation group(P>0.05). Compared with model group, the expression of GLUT1 and GLUT4 increased visibly in the QDTMT high dosage group, QDTMT low dosage group and Diltiazem Hydrochloride group(P<0.05). Compared with the Diltiazem Hydrochloride group, the expression of GLUT1 and GLUT4 had no change in QDTMT high dosage group(P>0.05), but decreased in the QDTMT low dosage group(P<0.05).3. GLUT1 and GLUT4 in myocardial cytomembrane were not visibly expressed in control group and sham operation group, but they were obviously expressed in model group and markedly increased in the QDTMT high dosage group, QDTMT low dosage group and Diltiazem Hydrochloride group.Conclusions1. QDTMT is effective for decreasing myocardial glycogen consumption in rats with myocardia IRI. It may be one of the mechanisms that QDTMT lessens the myocardial IRI.2. QDTMT is also effective for promoting the expression of total GLUT1 and GLUT4 in rats with myocardia IR and furthering the translocation of GLUT1 and GLUT4 to cell membrane to improve myocardial glycometabolism. This may be another mechanism that QDTMT resists the myocardial IRI.
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