ABSTRACT
Objective Diabetic mice models were established.Hearts were separated from the body,reperfused after ischemia,and disposed of with the extraneous calcitonin gene-ralated peptide (CGRP),to prove if the CGRP had protective effect on the early-staged diabetic mice with cardiac ischemia.Method ICR mice were injected with Streptozocins intraperitoneally to establish diabetic model.The model mice and the normal mice were randomly divided into 4 groups:two diabetic groups,two control groups.Hearts of the experimental mice were taken out from the chest cavity alive,and hanged on the Langendorff steadily for 30min.Western blot and radioimmunoassay techniques were used to test expression of Vanilloid receptor(VR1) and CGRP in myocardic tissue;Madlab system was used to test the cardiac function,which including left ventricular end-diastolic pressure (LVEDP),left ventricular developed pressure (LVDP),heart rate (HR),and coronary artery flow (CF),in the process of ischemic reperfusion,And ELISA assay kit was used to measure the concentration of the lactate dehydrogenase (LDH) in perfusion fluid collected from the heart.Result Expressions of VR1 and CGRP in diabetic hearts were significantly lower than those in normal ones 2 weeks later(P＜0.01).By comparing with normal hearts,diabetic hearts had higher LVEDP and CF (P＜0.05),and lower LVDP and HR(P＜0.05).However,release of LDH were lower than normal ones (P＜0.05).Predisposition of normal and diabetic hearts with CGRP can improve the cardiac function after ischemie injury.And the beneficial effect was more profound in early-staged diabetic hearts than in normal ones.Conclusion The diabetes disease(DM) can impair the expression of CGRP in myocardiac tissue.The extraneous CGRP may exert more potent protective effect on cardiac function in the early-staged diabetic heart.