1型糖尿病大鼠心肌缺血再灌注在体模型的时效研究

Research about prescription of an in vivo myocardial ischemia-reperfusion injury model in type 1 diabetes mellitus rats

目的：探讨在1型糖尿病（T1 DM）基础上如何有效建立大鼠在体心肌缺血再灌注（IR）模型．方法：SPF级SD雄性大鼠72只，随机分为6组（N1、N2、N3、T1、T2、T3组），N1、N2、N3组血糖正常，T1、T2、T3组实施尾静脉注射65 mg/kg剂量链脲佐菌素（STZ）T1DM造模，N1、T1组IR时间为30/90 min，N2、T2组IR时间为60/90 min， N3、T3组IR时间为60/180 min，每组12只．T1DM造模成功后，与正常血糖大鼠均饲养8 w，麻醉后开胸行心肌缺血再灌注，再灌注结束后经右颈静脉注入伊文思蓝染色，剪下大鼠心脏并洗净置于-80℃，冻结后应用心肌切片模具将心脏切成1 mm厚度薄片，置于含质量分数1％TTC与10％甲醛的磷酸盐缓冲液中染色固定，37℃下避光静置20 min，取出切片拭净残液，数码相机拍照，应用ImageJ图像处理软件计算心肌梗死面积．结果：N1、N2、N3、T1、T2、T3组心梗面积分别为（31.08±7.78）％、（39.31±11.89）％、（39.18±8.33）％、（32.16±9.57）％、（44.96±9.07）％、（45.99±12.10）％，N1组与N2、N3组之间差异均有统计学意义（P＝0.042，P＝0.046），T1组与T2、T3组之间差异均有统计学意义（P＝0.008，P＝0.010），N1组与T1组之间差异无统计学意义（P＝0.785），N2组与T2组之间差异有统计学意义（P＜0.05），N3组与T3组之间差异有统计学意义（P＜0.05）．结论：大鼠在体IR中缺血60 min模型的心梗面积显著大于缺血30 min模型，在T1 DM状态下，最佳心肌缺血时间在30～60 min之间．

Aim：To investigate a reliable method of in vivo model of myocardial ischemia-reperfusion （IR）injury based on type 1 diabetes mellitus（T1 DM）in rats.Methods：Seventy-two male SD rats were randomly divided into 6 groups（N1,N2,N3,T1,T2,T3;n=12）,of which 3 groups are with normal glu-cose levels（N1,N2,N3）and the other 3 are STZ-induced T1DMrats,dosed 65 mg/kg by caudal vein in-jection.All rats are respectively subjected to 30/90 min（N1,T1）,60/90 min（N2,T2）and 60/180 min （N3,T3）IR duration.All rats were raised for 8 weeks after induction of T1DM.Myocardium was dyed by jugular vein injection of evans blue when IR model was made in vivo,then cut off and transfered to-80 ℃fridge.1 mm-thickness myocardial biopsy was made by a specific slice mould.Photographs were taken after slices were immobilized in 1%TTC and 10%methanal solution for 20 min in dark,then ana-lyzed with software to determine the infarct size.Results：The infarct size in groups N2 and groups N3 nbsp;were stastically larger than in group N1 respectively（P=0.042,P=0.046）,while the infarct size in group T2 and group T3 were also larger than in group T1（P=0.008,P=0.010）.There is no significant difference in the infarct size between group N1 and group T1.Conclusion：Compared to 30 min-ischemia model,the infarct size in 60 min-ischemia model is signally larger for in vivo IR model of rats.The best ischemia duration of IR model is between 30 to 60 minutes In T1 DM rats.