The Protective Effect Of The Myocardial Ischemic Postconditioning On Ischemicreperfused Myocardium (I/R) Of Diabetic Rat And Their Relation With P-Akt

BacgroundPostconditioning and ischemic preconditioning are organisms on ischemic-reperfused injury in a natural protective mechanism,Their are have some effects and signal transduction pathways similar,For example,PI3k-Akt,Extracellular signal transduction pathway and so on.And the both may be inhibit the mPTP of Mit from opening hole to protect myocard.This study describes the protective effect of the myocardial ischemic postconditioning on ischemic-reperfused myocardium(I/R)of diabetic rat and Signaling mechanism.Materials and Methods1.Animals:healthy SD rats weighing 250-300g2.Protocols:①Bank control group②Ischemia-reperfusion groupc③Postconditioning group④Diabetic postconditioning group⑤Diabetic Ischemia-reperfusion group⑥Diabetic blank control group.Rats in each group were randomly selected 10.3.Diabetic rat model of production methods:With STZ intraperitoneal injection of 65mg/kg,Two consecutive blood glucose measurements≥16.65mmol/L after 48h.And drinking,foodding,polyuria,weight loss,such as the performance model is to determine the success of diabetes.4.Surgical procedures:All rats were used intraperitoneal injection of chloral hydrate anesthesia.Intraperitoneal injection of heparin 500U / kg before open chest 5 min.The hearts were quickly made an incision at the base of the heart and put in ice-cold K-H solution.Gently squeeze the heart hematocele from the heart cavity. Rapid aortic cannulation would be fixed in the heart of non-circulating Langendorff isolated rat heart perfusion system.Cardiac perfusion temperature maintained at 36℃.5.Myocardial specimens taken time,location and preservation methods: Specimens in each group of myocardial perfusion in the balance after the end of study,was cut the size of soybean grain.Specimens were be use by western blot and Electron microscopy.6.Detect indicators:Heart coronary perfusion flow,Determination of myocardial infarct size,western blot and changes in myocardial and mitochondrial by Electron microscopy.7.Statistical analysis:All analysis were performde with the SPSS11.0.Data were experssed as the means±SD.One-way ANOVA and Student-Newman-Keuls post test were used to compare the significance between the groups.P＜0.05 was considered significant.Results1.Diabetic rats average blood glucose concentration is(23.15±2.16)mmol/ L, Non-diabetic rats average blood glucose concentration is(4.16±0.31)mmol/L.Two groups of rats with blood glucose concentration have significant Differences(P＜0.01).2.Determination of reperfusion beginning of the first minutes of coronary flow 2,10,120.At the 2 minutes postconditioning group with ischemia-reperfusion group have statistically significant(P＜0.05).3.postconditioning group and ischemia-reperfusion group compared to the scope of myocardial infarction have statistical significance(P＜0.05).Diabetic rats than healthy rats in ischemia-reperfusion group the myocardial infarction range bigger and has statistical significance(P＜0.05).4.Western blot determination P-Akt:Post group and IR group,Dpost group and DIR group have statistical significance(71.5±4.8vs45.2±3.4,81.2±4.6vs46.5±3.6).5.Myofilament obvious fracture with a wide range of changes in mitochondrial vacuolation in IR group and DIR group.The degree integrity of Myocardial fibers and mitochondrial in Post group and Dpost more than in IR group and DIR group. Conclusionpostconditioning in diabetic ischemic isolated rat heart also has protective effects. This role may be associated with Akt activation.