| Objective:To investigate the effect of mitochondrial fusion protein 2(Mfn2) recombinant adenovirus over-expression on myocardial ischemia reperfusion injury and apoptosis of sevoflurane postconditioning in diabetic rats and for myocardial protection in patients with diabetes mellitus provide new target and theoretical basis. Methods:(1) Myocardial ischemia reperfusion model were established in diabetic rats.Forty-five male SD rats,weighing 210~260g,were divided into sham operation group(NC),diabetic model group(DMS)and myocardial ischemia reperfusion injury in diabetes mellitus(DMIR),15 rats in each group.Rats in DMIR group were given streptozotocin(STZ60mg/kg) and induced by occlusion of the left coronary artery for 30 min followed by 120 min reperfusion.Rats in NC group were injected same amount of sodium citrate buffer as control.Rats in DMS group were received streptozotocin(STZ60mg/kg).Respectively measuring fasting blood glucose,body weight(including wet heart weight and left ventricular mass),urine volume,the amount of water before modeling,after injection of STZ(1,2,3 and 4 weeks).After the success of the model,the area of myocardial infarction were tested.HE staining to observe the myocardial pathological damage degree.(2) To investigate the effect of Mfn2 recombinant adenovirus(Adv-Mfn2) over expression for sevoflurane postconditioning on myocardial ischemia reperfusion injury in diabetic rats and apoptosis effect. Experiments with reference to the first part manufacturing diabetic myocardial ischemia reperfusion injury model,with random number table method, Forty-five male SD rats,weighing 210~260g,were divided into 5 groups(n=9) : diabetic sham operation group C, diabetic myocardial ischemia reperfusion group I, diabetic myocardial ischemia reperfusion+sevoflurane postconditioning group IS, diabetes myocardial ischemia reperfusion and empty vector+sevoflurane postconditioning group IAS and myocardial ischemia in diabetes after perfusion+Mfn2 recombinant adenovirus+sevoflurane postconditioning groupIMS.The rats in group I induced by occlusion of the left coronary artery for 30 min followed by 120 min reperfusion.In IS group,sevoflurane was inhaled 5 minutes before reperfusion,and reperfusion 120 min later,and In IAS group,first, were injected with empty vector(Adv),the rest part as group IS.IMS group rats were anesthetized,and then in the apical injection Ad-Mfn2 adenovirus and the rest part was similar with the treatment of group IS.The rats were sacrificed at 120 min of reperfusion,measuring the concentration of creatine kinase isoenzyme(CK-MB) and cardiac troponin I(cTnI) and myocardial tissues were taken for determination of the contents of myocardial Mfn2 and myocardial apoptosis index(AI).The ultrastructure of myocardium was examined with electron microscope.Results:(1) NC group rats increased gradually with the weight of time activity,bright white hair.In diabetic rats(DMS and DMIR) modeling after 1 week,blood glucose value all expressed 16.7mmol/L,and modeling in the 1,2,3 and 4 weeks was stable at a high level,diabetic rats(DMS and DMIR) had a different with blood glucose,weight,water intake and urine volume compared with same time NC group(P<0.05).With the prolongation of diabetic rats,decreased activity,weight loss,subcutaneous fat was significantly reduced,loose and dull yellowish fur.Compared with the NC group,the body weight,heart wet weight and left ventricular mass were reduced,and myocardial infarction size were increased(DMIR) in DMS group and DMIR group.Compared with the DMS group,DMIR group rats body weight and heart wet weight and left ventricular mass difference no statistical significance,but the area of myocardial infarction were increased(P<0.05).In NC group,myocardial structure clear and tidy,uniform staining,cell morphology was normal.DMS group myocardial fibers arranged neatly, cells with mild edema,visible amounts of inflammatory cells infiltration.DMIR group myocardial cell swelling and myocardial fiber diffuse ischemia necrosis, arranged in an irregular,fracture,shape distortion,border is not clear.(2) Compared with group C,group I,group IS,group IAS,and group IMS rat serum CK-MB,cTnI and AI of myocardial cells were increased,myocardial pathological damage aggravated,and myocardial Mfn2 expression were down regulated in group I,group IS and group IAS,and was up-regulated in group IMS(P<0.05).Compared with I group,the CK-MB,cTnI and AI were decreased,the expression of myocardial Mfn2 was up-regulated in group IMS(P<0.05).Compared with IS group,the CK-MB,cTn I and AI in myocardial cell were decreased,the expression of myocardial Mfn2 was up-regulated in group IMS(P<0.05).Compared with IAS group,the CK-MB,cTn I and AI in myocardial cell were decreased,the expression of myocardial Mfn2 was up-regulated in group IMS(P<0.05).The CK-MB,cTnI and AI in the myocardial cells and myocardial Mfn2 expression showed no significant difference in group I,group IS and group IAS(P>0.05),and myocardial pathological changes is not obvious. Conclusion:(1) Myocardial ischemia reperfusion in diabetic model by intraperitoneal injection of streptozotocin(STZ,60mg/kg) and ligation of the LAD model,which modeling method is simple,high success rate,good stability,is related to myocardial ischemia animal model of diabetes ideal.The diabetic rats after glucose and urine volume around the basic stability,is the best time for the heart of IR.(2) Diabetes can cancel sevoflurane treatment protective effect on myocardial ischemia reperfusion injury and its mechanism may be associated with the down-regulation of expression of Mfn2 in the myocardium of diabetic rats.Mfn2 gene recombinant adenovirus expression may achieve the recovery of sevoflurane treatment protective effect on myocardial ischemia reperfusion injury, the mechanism may related to increase mitochondrial fusion of Mfn2 and maintain homeostasis of mitochondria and reduction of cell apoptosis. |
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