缺血预处理对糖尿病大鼠心肌梗死和细胞因子的影响

The influence of preconditioning for myocardial ischemia on the myocardial infarction and the cytokines in diabetic rats

目的 观察大鼠心肌梗死面积和细胞相关因子的变化 ,探讨缺血预处理 (IP)对缺血 再灌注 (I/R)糖尿病大鼠心肌的保护作用。 方法 向健康SD大鼠腹腔内注射链脲佐菌素 (每只 6 0mg/kg)制造糖尿病大鼠模型。 2d后测定血糖 ,将血糖≥ 11 1mmol/L定为糖尿病大鼠 ,共 39只。 2周后 ,麻醉大鼠 ,开胸结扎冠状动脉左前降支 (LADCA)复制IP和I/R模型。将 39只糖尿病大鼠分为IP组、非缺血预处理 (NIP)组、对照组 ,每组 13只。记录Ⅱ导联心电图 ,测定心腔血清肌酸激酶同工酶(CK MB)、白细胞介素 8(IL 8)、肿瘤坏死因子α(TNFα)、心肌组织丙二醛 (MDA)、超氧化物歧化酶(SOD)含量。取心脏切片染色 ,计算心肌缺血范围和心肌坏死范围。 结果 IP组和NIP组间心肌缺血范围分别为 46 6 %和 48 6 % ,无显著性差异 ,心肌坏死范围分别为 6 4 8%和 32 6 % (P <0 0 1)。IP组再灌注期室性心律失常减少 ,尤其是室颤较NIP组显著减少 5 2 9% (P <0 0 1)。IP组CK MB和TNFα及MDA显著低于NIP组 (P <0 0 5 )。 结论 缺血预处理可通过减少TNFα和抗氧化作用 ,减少心肌坏死范围和降低糖尿病大鼠室颤的发生 ,从而减轻糖尿病大鼠心肌I/R的严重损害。

Objective To study the protective role of the myocardial ischemic preconditioning(IP) on myocardial infarction of diabetic rat by means of observing the infarction areas and cytokines. Methods The diabetic rat model was established by streptozotocin injection (60 mg/kg body weight) to the abdominal cavities of Spraque Dawlay(SD) rats. Two days later, the diabetic rats were considered diabetes mellitus according to blood sugar≥11 1mmol/L. Two weeks later, the myocardial IP and I/R models were established by ligature and opening left anterior descending coronary artery (LADCA) in anesthetic SD rats. Thirty nine SD rats were divided into three groups with each group 13 rats (diabetic rat IP group, diabetic rat non IP group and diabetic rats control group). The II lead ECG was recorded continuously. The areas of the myocardial ischemia and necrosis were calculated. The levels of serum CK MB, IL 8 and TNFα were determined. The MDA and cu zn SOD were assessed in myocardial tissues. Results The areas of the myocardial ischemia were not different in IP and NIP groups (46 6% and 48 6%, P >0 05), While the areas of myocardial necrosis in IP and NIP groups were 64 80% and 32 60%, respectively( P <0 01). The ventricular arrhythmias decreased in IP group during reperfusion period and the ventricular fibrillation arrhythmia decreased more significantly than that of NIP groups(52 9%, P <0 01). The levels of serum CK MB and TNFα,and myocardium MDA in IP group decreased more significantly than that of NIP group ( P <0 05). Conclusions The myocardial ischemic preconditioning markedly reduced the myocardial necrosis areas and the happening of the ventricular fibrillation arrhythmias in the diabetic rats during the ischemic reperfusion period as a result of decreased TNFα and anti oxidation.