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目的:探讨一定周期较大强度耐力运动预处理后大鼠缺血再灌注(I/R)心肌SOD2蛋白表达及其活性变化与心肌保护效应的关系。方法:成年雄性SD大鼠36只,随机分为假手术对照组(A)、心肌缺血再灌注组(B)、较大强度耐力运动+心肌缺血再灌注组(C)。C组在运动干预后与B组一同建立在体I/R(缺血30 min,再灌注60 min)心肌模型。造模过程中观察心电图J点变化,每组选取造模成功者8例进入后续实验。测定血清c Tn I、CK-MB浓度;Western Blotting法测定心肌SOD2蛋白表达水平,测定心肌SOD2、T-SOD活性及MDA含量。结果:B、C组心电图J点、T波值及Q-T间期于心肌缺血30 min时显著增加及延长,而再灌注60 min时的J点基本恢复、T波低平。B组SOD2蛋白表达水平显著高于A组,C组又显著高于B组。造模结束后,B、C组MDA含量及c Tn I、CK-MB浓度显著升高,同时SOD2活性及T-SOD活性显著下降;上述异常变化均以B组更明显。结论:较大强度耐力运动预处理可能通过提高I/R心肌SOD2蛋白表达,缓解SOD2活性下降及活性氧代谢水平升高程度,发挥心脏保护效应。
Objective: To investigate the relationship between myocardial SOD2 protein expression and myocardial protective effect after myocardial ischemic reperfusion (I / R) myocardial preconditioning in a certain period of time. Methods: Thirty - six adult male Sprague - Dawley rats were randomly divided into sham operation control group (A), myocardial ischemia - reperfusion group (B), intensive endurance exercise + myocardial ischemia reperfusion group (C). In group C, myocardial I / R (ischemia 30 min, reperfusion 60 min) was established together with group B after exercise intervention. In the process of modeling, we observed the J-point changes of electrocardiogram, and selected 8 successful cases in each group to enter the follow-up experiment. The concentrations of cTn I and CK-MB in serum were measured. The expression of SOD2 protein in myocardium was measured by Western Blotting. The activity of SOD2, T-SOD and the content of MDA were measured. Results: The J point, T wave and Q-T interval in group B and group C were significantly increased and prolonged at 30 min after myocardial ischemia, while J point at 60 min after reperfusion was recovered and T wave was low. The level of SOD2 protein in group B was significantly higher than that in group A, while it was significantly higher in group C than that in group B. After modeling, the content of MDA and the concentrations of cTn I and CK-MB in group B and group C increased significantly, while the activity of SOD2 and the activity of T-SOD decreased significantly. The abnormal changes were more obvious in group B than those in group B. CONCLUSION: Greater intensity endurance exercise preconditioning may exert cardioprotective effects by increasing the expression of SOD2 protein in I / R myocardium, alleviating the decrease of SOD2 activity and the level of reactive oxygen metabolism.