大鼠体外循环心肌胰岛素抵抗实验模型的建立

目的构建大鼠体外循环(CPB)心肌缺血再灌注损伤(MIRI)实验模型并评估其诱导心肌胰岛素抵抗(IR)的效果。方法12只雄性SD大鼠采用随机数字表法分为两组,对照组不阻断主动脉(n=6),模型组主动脉阻断30 min再灌注15 min(n=6);经尾动脉置入灌注管、右侧颈外静脉插入右心房引流管、开胸阻断升主动脉,建立体外循环(CPB),于开放主动脉后15 min采集血液及心肌组织标本,检测血浆葡萄糖、胰岛素水平并进一步计算葡萄糖摄取率、胰岛素抵抗指数(IRI)的变化。采用蛋白质印迹法(Western blot)、免疫荧光检测心肌细胞膜葡萄糖转运蛋白4(GLUT4)的表达。组间比较采用独立样本t检验。结果缺血再灌注后15 min,模型组[静脉葡萄糖浓度(Glu-V)(20.23±0.30)mmol/L;胰岛素浓度(15.89±1.72)mIU/L;IRI(14.29±1.59)]高于对照组[Glu-V(8.31±0.67)mmol/L;胰岛素浓度(6.54±1.77)mIU/L;IRI(2.42±0.73),t=38.945、9.286、16.593,P值均<0.01],差异有统计学意义。而模型组葡萄糖摄取率为(7.68±2.29)%低于对照组[(45.46±3.67)%,t=21.410,P<0.01],差异有统计学意义。模型组左心室收缩压(LVSP)为(34.8±6.6)mmHg低于对照组LVSP[(60.4±6.9)mmHg,t=-6.586,P<0.01],差异有统计学意义。模型组Western blot所测心肌细胞膜蛋白相对表达量为(0.30±0.08)低于对照组(1.04±0.21,t=7.979,P<0.01),差异有统计学意义。结论成功建立操作简便、经济适用、个体差异小且更能模拟临床的CPB缺血再灌注心肌IR大鼠模型。

Establishment of myocardial insulin resistance model in rats during cardiopulmonary bypass

Objective To establish an experimental model of myocardial ischemia-reperfusion injury(MIRI)induced by cardiopulmonary bypass(CPB)in rats and evaluate its effect on myocardial insulin resistance(IR).Methods A total of 12 sprague-dawley(SD)rats purchased from Experimental Animal Center of Guizhou Medical University were divided into two groups by random number table method:control group,no aortic occlusion(n=6);model group,aortic occlusion for 30 min and reperfusion for 15 min(n=6).The CPB was established by placing perfusion tube through caudal artery,intubation from right external jugular vein to right atrium and right femoral vein for drainage.The blood samples of carotid artery,right atrium and left ventricular apical tissue were collected 15 min after the aorta was opened.Plasma glucose and insulin levels were detected,and the changes of glucose uptake rate and insulin resistance index(IRI)were calculated.The expression of glucose transporter 4(GLUT4)was analysis by Western blotting and immunofluorescence.Independent sample t test was used for comparison between groups.Results At 15 min after myocardial ischemia-reperfusion,in the model group venous glucose(glu-v)[(20.23±0.30)mmol/L],insulin concentration[(15.89±1.72)mIU/L],and IRI[(14.29±1.59)]were higher than in the control group[glu-v:(8.31±0.67)mmol/L;insulin concentration:(6.54±1.77)mIU/L;IRI(2.42±0.73);t=38.945,9.286,16.593,P<0.01].The glucose uptake rate in the model group was(7.68±2.29)%,lower than that in the control group[(45.46±3.67)%,t=21.410,P<0.01].Left ventricular systolic pressure(LVSP)in the model group was(34.8±6.6)mmHg,lower than that in the control group[(60.4±6.9)mmHg,t=-6.586,P<0.01].The relative expression of myocardial cell membrane protein in the model group(0.30±0.08)was lower than that in the control group(1.04±0.21,t=7.979,P<0.01).Conclusion We have successfully established a CPB ischemia-reperfusion myocardial IR rat model which is easy to operate,economical and applicable,with less individual difference and closer to clinical practice.