缺血预适应对糖尿病大鼠再灌注心肌的保护作用

目的　通过建立大鼠缺血预适应 (IP)模型 ,探讨IP对缺血 再灌注 (I/P)糖尿病大鼠心肌的保护作用。方法　在SD大鼠腹腔内注射链佐星 (6 0mg/kg)制造糖尿病大鼠模型。 2d后 ,随机时刻测定血糖 ,将血糖≥ 11.1mmol/L定为糖尿病大鼠 2 2只 ,另外 2 2只血糖正常鼠为非糖尿病鼠。 2周后 ,麻醉大鼠 ,结扎和放松冠状动脉左前降支(LAD)复制IP和I/P模型。将 44只大鼠分为IP糖尿病大鼠组 (DIP组 )、IP非糖尿病大鼠组 (NDIP组 )、非IP糖尿病大鼠组 (DNIP组 )和非IP非糖尿病大鼠组 (NDNIP组 )各 11只。记录II导联心电图。取心脏切片染色 ,计算心肌缺血范围和心肌坏死范围。结果　各组间心肌缺血范围无显著差异 (P >0 .0 5 )。DIP组心肌坏死范围较DNIP组明显减小 (P <0 .0 1)。DNIP组室性心律失常增多 ,尤其心室颤动较其他各组显著增多 (P <0 .0 1)。结论　缺血预适应可以减轻糖尿病大鼠随后较长时间缺血 再灌注对心肌的严重损害 ,能减少心肌坏死范围和降低心室颤动的发生率。

The protective effect of the myocardial ischemic preconditioning on ischemic-reperfused myocardium (I/P) of diabetic rat

Objective To investigate the protective effect of the myocardial ischemic preconditioning(IP) on ischemic reperfused myocardium (I/P) of diabetic rat.Methods The diabetic rat model was established by intraperitoneal injection of streptozotocin (60 mg/kg).After two days,the rats showing blood sugar≥11.1 mmol/L were considered to have diabetes.After two weeks,the myocardial IP and I/P models were established by ligating and opening left anterior descending branch (LAD) of coronary artery.Forty four SD rats were divided into four groups (diabetic rats IP group,DIP group;non diabetic rats IP group,NDIP group;diabetic rats non IPgroup,DNIP group;non diabetic rats non IP group,NDNIP group) of 11 rats each.ECGs of lead Ⅱ were recorded continuously.The sizes of areas of the myocardial ischemia and necrosis were calculated.Results The sizes of areas of the myocardial ischemia were not different between various groups (P>0.05). The size of area of myocardial necrosis in DIP group was significantly smaller than that in DNIP group(P<0.01). The ventricular arrhythmia increased in DNIP group,especially,the ventricular fibrillation increased significantly as compared with that in other groups(P<0.05).Conclusion The myocardial ischemic preconditioning could markedly reduce myocardial necrosis and ventricular fibrillation induced by ischemic reperfusion injury.