The Influence Of Protease Activated Receptor-2on NF-κBp65Expression Of Cardiomyocytes With Ischemic Preconditioning Rats

Objective To study the effects of the specificity agonists of protease activated receptor-2(SLIGRL-NH2) preconditioning on the expression of NF-κBp65during ischemic preconditioning in rats hearts, and investigate the possible mechanism and cardioprotective effects.Methods60male Sprague-Dawley rats were anesthetized with20%urethane intraperitoneal (5ml/kg), and intraperitoneal injections of heparin sodium500u/kg, rapidiy removed of the heart. Immediately hung the heart on the Langendorff shelf after4℃saline washed away the remainder. Perfusion fluid was constitute with95%O2+5%CO2saturated Krebs-Henseleit (K-H). Retrograde perfusion fluid through the aorta of non-recirculating perfusion heart. Flow rate is controlled by the constant flow pump for6ml/min. Perfusion process with constant temperature water bath to maintain constant temperature of37℃. All the hearts balance the infusion for15minutes, and all the heart were randomly divided into the following5groups after infusion, each group is made up of12hearts.(1) group A is normal control group:K-H liquid continuous infusion95minutes.(2) group B is ischemia-reperfusion group:K-H liquid perfusion for35minutes after the heart and the heart heat preservation moisture, stop the infusion45minutes before15minutes of reperfusion.(3)Group C is ischemic preconditioning group (IPC): K-H liquid heart perfusion for ischemic pretreatment operation5minutes. And Reperfusion were for5minutes after stopping perfusion5minutes,the process repeated three times, at last reperfusion were for15minutes after stopping perfusion45minutes.(4) D group is SLIGRL-NH2in Low-dose pretreatment group(SLIGRL-NH2in low-dose group):K-H liquid heart perfusion5minutes ischemic preconditioning operation, stopping irrigation after5minutes, containing SLIGRL-NH2(based on the body weight of rats at0.5mg/kg basis) KH solution perfusion5minutes, this process repeated three times, and then stopping irrigation45minutes, at last reperfusion were for15minutes.(5)E group is SLIGRL-NH2in high dose pretreatment group (SLIGRL-NH2high dose group):the methods were same as group D, but SLIGRL-NH2contented in K-H solution perfusion after calculated according to weight (3mg/kg). we collected the coronary effluent before the end of10minutes in the experiment, using biochemical analyzer to measure myocardial enzymes. death myocardial area was measured by Image Pro Plus analysis system, the expression level of NF-κBp65in myocardial tissue was measured by Western Blot.Results Compared with normal control group, each group of myocardial necrosis in different degree (P<0.05); the dead myocardial area of ischemic preconditioning group is less than ischemia-reperfusion group (P<0.05);Compared with ischemic preconditioning group, SLIGRL-NH2pretconditioning in low-dose group reduces the dead myocardial area is significantly (P<0.05); Compared with SLIGRL-NH2pretconditioning in low-dose group, SLIGRL-NH2pretconditioning in high dose group had a significantly reducing dead myocardial area (P<0.01); Compared with normal control group, each group of creatine kinase and lactate dehydrogenase, myoglobin were increased(P<0.05);Compared with ischemia-reperfusion group, creatine kinase and lactate dehydrogenase, myoglobin of ischemic preconditioning group were lower (P<0.01);Compared with ischemic preconditioning group, creatine kinase and lactate dehydrogenase, myoglobin of SLIGRL-NH2pretconditioning in low dose group were reduced significantly (P<0.05); Compared with SLIGRL-NH2pretconditioning in low-dose group, creatine kinase and lactate dehydrogenase, myoglobin of SLIGRL-NH2pretconditioning in high-dose decreased significantly (P<0.05);Compared with control group, I/R caused a marked increase in the expression of NF-κBp65(P<0.01). Compared with I/R group, IPC group caused a marked decrease in the expression of NF-κBp65(P<0.05). Compared with IPC group, SLIGRL-NH2pretconditioning in low doses group caused a marked decrease in the expression of NF-κBp65(P<0.05). Compared with SLIGRL-NH2pretconditioning in low doses group, SLIGRL-NH2pretconditioning in heavy doses group caused a remarkable decrease in the expression of NF-κBp65(P<0.05).Conclusion Specificity agonists of Protease activated receptor2plays a protective effect on ischemic preconditioning myocardial; through regulates expression of NF-κBp65in myocardial tissue and inhibits myocardial cell death may be one of important mechanism which protease-activated receptor2plays myocardial protection.