注射用心肌肽预处理对大鼠未成熟心肌缺血再灌注损伤的保护作用及其机制

目的:探讨注射用心肌肽预处理对幼鼠未成熟心肌缺血再灌注损伤的保护作用,阐明其相应的作用机制.方法:通过结扎SD幼鼠冠状动脉左前降支建立缺血再灌注损伤模型.SD大鼠随机分为假手术组、模型对照组及注射用心肌肽预处理组(CMP组).检测血清乳酸脱氢酶(LDH)、肌酸磷酸激酶同工酶(CK-MB)、肌钙蛋白T (Tn-T)和心肌...

Protective effect of cardiomypeptidin for injection preconditioning on immature myocardial ischemia - reperfusion injury in young rats and its mechanism

Objective To investigate the protective effect of cardiomyopeptidin(CMP) for injection preconditioning on the immature myocardial ischemia-reperfusion injury in young rats,and clarify its mechanism.Methods 30 young healthy SD rats were randomly divided into sham-operated group,model control group and CMP group(n=10).The levels of serum lactic dehydrogenase(LDH),creatine kinase MB(CK-MB),troponin Tn-T were detected;the contents of superoxide dismutase(SOD),malondialdehyde(MDA),nitric oxide(NO),total nitric oxide synthase(TNOS),inducible nitric oxide synthase(iNOS)and endothelial nitric oxide synthase(eNOS)in myocardium tissue were measured;the expression levels of iNOS,eNOS and Caspase-3 protein in myocardial tissue were detected by immunohistochemical method.The expressions of iNOS,eNOS and Caspase-3 mRNA in myocardial tissue were measured by real-time fluorescence quantitative PCR.The changes of myocardial structures were observed with optical microscope and transmission electron microscope.The apoptosis of myocytes was observed by TUNEL.Results Compared with model control group,the levels of LDH,CK-MB,Tn-T in CMP group were decreased(P<);Compared with sham-operated group,the contents of MDA,SOD,TNOS,and iNOS were increased and the expression levels of iNOS and caspase-3 mRNA were significantly down-regulated in CMP group,but less than those in model control group(P<0.01 or P<0.05).Several pieces of myocardial hemorrhage and inflammatory cell infiltration were observed in model control group,severe degeneration and necrosis of myocytes could be found,the apoptotic myocytes were significantly increased;while in CMP group,the myocardial pathological injuries were mitigated,only mild degeneration and necrosis of myocardial cells could be found,the vascular structure was near-complete,the number of apoptotic myocytes between sham operation group and control group.Conclusion Cardiomyopeptidin for injection preconditioning can protect immature myocardium against ischemia-reperfusion injury in young rats.The mechanism may be associated with reducing oxygen free radical(OFR) and NO production,inhibiting the expressions of iNOS mRNA,Caspase-3 mRNA and Caspase-3 protein in myocytes,and reducing apoptosis.