The Protection Of The Caspase-3Inhibitor On CPB-induced Cardiac Function Injury

Objectives and background:Myocardial ischemia-reperfusion injury is a important factor of heart dysfunction after the heart surgery via cardiopulmonary bypass. A large number of experimental studies suggest that the cardiomyocyte apoptosis is a main pathological features of myocardial ischemia-reperfusion injury. Myocardial ischemia reperfusion injury is not only through the heart dysfunction after cardiopulmonary bypass heart surgery, but also to start and induce other organ dysfunction/injury led to multiple organ dysfunction syndrome important initial factor. Pathophysiology of ischemia-reperfusion injury, the mechanism of its biological effects are one of the hot area of much concern in the medical and other biological sciences disciplines over the years. Its research significance is not only for the cell/molecular level to reveal the molecular basis of ischemia-reperfusion injury, but more important is a major impact of the problem in clinical medicine of many fields common ischemia-reperfusion injury prevention. The research caspase-3inhibitor myocardial protection during cardiopulmonary bypass can be for clinical cardiopulmonary bypass heart surgery’s myocardial ischemia-reperfusion injury prevention to provide important theoretical basises. Methods:30clean and healthy New Zealand white rabbits (male or female), body weight (2.0-2.5) kg, were randomly divided into control and experimental groups, and simulated clinical rat cardiopulmonary bypass model. Experimental groups:the inhibitor of caspase-3——Ac-DEVD-CHO (A group), half an hour prior to the surgery through the femoral vein of the New Zealand white rabbits give Ac-DEVD-CHO3mg/kg, after the end of cardiopulmonary bypass through the femoral vein to give Ac-DEVD-CHO3mg/kg again; control group:5%ethanol saline (C group), half an hour prior to the surgery through the femoral vein of the New Zealand white rabbits give5%ethanol saline3mg/kg, after the end of cardiopulmonary bypass through the femoral vein to give5%ethanol saline3mg/kg again.With the beginning of the cardiopulmonary bypass, at the bypassing20min, stopped cardiopulmonary bypass1h and stopped cardiopulmonary bypass3h, four point take venous blood lml-2ml, and immediately centrifuged and frozen the plasma reserved for detection of creatine kinase isoenzyme (CK-MB), cardiac troponin (cTnI), the activity of caspase-3and myeloperoxidase (MPO) activity. Such as, cTnl and CK-MB concentrations were measured by ELISA; Caspase-3activity assay:Caspase-3activity was measured by fluorescence spectrophotometer; Detection of myeloperoxidase (MPO):In accordance with the myeloperoxidase (MPO) detection kit; Using TUNEL method, situ nick end labeling method, detect myocardial apoptosis. And observe histopathological changes in myocardial cells after cardiopulmonary bypass using light microscopy and electron microscopy ultrastructural changes in myocardial cells after cardiopulmonary bypass. Data were statistically analyzed using SPSS13.0statistical software, and the measurement data are x±s said. Multiple samples are several completely randomized design one-way ANOVA, pairwise comparisons using LSD test.Results:1. In the different periods of cardiopulmonary bypass CPB cardiac troponin I (cTnI), creatine kinase isoenzyme (CK-MB), myeloperoxidase (MPO) activity and Caspase-3activity level changes:Cardiac troponin I (cTnl), creatine kinase MB (CK-MB), myeloperoxidase (MPO) in the CPB bypass and after cardiopulmonary bypass was significantly higher than the level before cardiopulmonary bypass (cardiopulmonary bypass CPB)(P＜0.05), and increased1h after reperfusion sharpest; to stop cardiopulmonary bypass (cardiopulmonary bypass CPB) and after1h of reperfusion, caspase-3activity increased, and continued to increase with reperfusion time prolonged.2. The influence of Caspase-3inhibitors——Ac-DEVD-CHO in cardiopulmonary bypass (CPB) with cardiac troponin (cTnI), creatine kinase isoenzyme (CK-MB), myeloperoxidase (MPO) and the activity of Caspase-3:At the point of hypoperfusion20min,at the end of cardiopulmonary bypass (CPB) and3h after the cardiopulmonary bypass (CPB), experimental group’s creatine kinase isoenzyme (CK-MB), cardiac troponin I (cTnI) serological levels were significantly lower than the corresponding control group (P＜0.05). Experimental group’s Caspase-3activity and myeloperoxidase (MPO) activity compared to the control group were significantly lower (P＜0.05).3. Light and electron microscope could observe that the the myocardial ultrastructure degree of injury of the experimental group’s were more slightly than the control group’s:Normal myocardial cells in the microscopic structure were seen that its cell structure integrity, muscle fibers arranged rules, cell quality no edema, mitochondrial shape and full and crest dense; the control group myocardial cells were seen that muscle fibers slender and partially denatured fracture, intercellular edema significantly, mitochondrialvisible swelling and reduce the crest;there were more slightly damage to the microscopic structure of the myocardial cells of the experimental group than the control group significantly; there were occasional TUNEL (+) myocardial cells in the normal myocardium, while the control group more TUNEL (+) cardiomyocytes, the experimental group TUNEL (+) myocardial cells compared with the control group decreased significantly (P<0.05).Conclusion: Apoptosis can cause the cardiopulmonary bypass’s myocardial ischemia-reperfusion injury, is also an important factor of influence heart function after cardiopulmonary bypass-heart surgery. Caspase-3’s specific inhibitor-Ac-DEVDCHO by inhibiting apoptosis after myocardial ischemia and reperfusion can reduce myocardial microstructure pathological damage and reaches a certain myocardial protection. In short, Caspase-3inhibitors play a protective role during heart function damage in/after cardiopulmonary bypass.