【作者】 陆晓；

【导师】 励建安； 周士枋； 张馥敏；

【作者基本信息】 南京医科大学 ， 运动医学， 2008， 博士

【摘要】 目的:在小型猪可控性心肌缺血动物模型上,观察运动诱发的适宜短暂性心肌缺血对缺血区域冠状动脉侧支循环生成的作用及其分子生物学机制。方法:小型猪开胸后在其左回旋支第一分支钝缘支装上水囊缩窄器。4周后,冠状动脉造影证实可控性心肌缺血动物模型建立。小型猪随机分为三组:第一组为假手术组,第二组为单纯缺血组,第三组为运动组。单纯缺血组每天通过水囊缩窄器注水加压使心肌产生短暂性缺血2次,缺血时间为每次2分钟;运动组除以上静息状态心肌缺血外,还需每天平板运动训练30分。运动训练方案根据运动试验结果确定:先做3分钟的准备活动,然后将平板速度渐升至中等强度(80%最大心率)运动10分钟,后继续升高平板速度至缺血阈强度(100%最大心率)运动2分钟,降低平板速度(80%最大心率)运动10分钟,然后再升至缺血阈强度运动2分钟,最后做3分钟的结束活动。单纯缺血组及运动组每周训练5天,共8周。假手术组在这8周中不作任何干预。在手术日及取材日注入不同颜色微球以测定训练前及训练后缺血区域相对心肌血流量(RMBF)。免疫组化Ⅷ因子染色测定毛细血管密度(CD),Western-Blot及Real time RT-PCR测定缺血心肌局部血管内皮细胞生长因子(VEGF)及其受体F1k-1的蛋白表达量及mRNA表达量,ELISA法确定血中肌钙蛋白(cTnI)含量,电镜及光镜检查缺血区域心肌细胞损伤情况以确定训练安全性。结果:运动组CD为9.35±0.97个/视野,显著高于单纯缺血组4.5±0.75个/视野(p＜0.01)及假手术组1.63±0.69个/视野(p＜0.01);单纯缺血组CD亦显著高于假手术组(p＜0.01)。运动组RMBF显著高于单纯缺血组(p＜0.01)及假手术组(p＜0.01);单纯缺血组的RMBF显著高于假手术组(P＜0.01)。运动组VEGF蛋白表达量显著高于单纯缺血组(P＜0.05)及假手术组(P＜0.01),F1k-1蛋白表达量运动组亦显著高于单纯缺血组(P＜0.05)及假手术组(P＜0.01);单纯缺血组VEGF(P＜0.05)及F1k-1(P＜0.05)的蛋白表达量显著高于假手术组。VEGF及F1k-1的mRNA表达量结果与蛋白表达量结果相似。运动组(p＞0.05)及单纯缺血组(p＞0.05)训练后CTnI与训练前相比无显著增加,光镜及电镜检查心肌细胞无明显异常。结论:在小型猪可控性心肌缺血动物模型上,运动诱导的适宜间断性心肌缺血可以安全有效地通过缺血心肌局部VEGF及其受体F1k-1的增加促进冠状动脉侧支循环的生成。更多还原

【Abstract】 Objective:To hypothesize that appropriate intermittent myocardial ischemia induced by exercise could safely promote coronary collateral formation in the ischemic area through the increased expression of vascular endothelial growth factor(VEGF)and its receptor fetal liver kinase-1(Flk-1).Design:A balloon constrictor was surgically implanted in the first obtuse marginal coronary artery(OM1)of Guangxi BA-MA miniature pigs The subjects were divided into 3 groups:sham-operated(SO),pure ischemia (PI),and exercise training(ET).Subjects in the ET group performed individualized treadmill programs with 2 episodes of exercise-induced ischemia for 8 weeks;2 pre-exercise episodes of pure ischemia induced by brief OM1 occlusion were also conducted.Only pure ischemia was induced in the PI group,and the SO group remained sedentary for the experimental period.VEGF and Flk-1 expression levels were measured by Western Blot and Real time RT-PCR analyses;capillary density by immunohistochemistry;relative myocardial blood flow by microspheres; and cardiac troponin I by enzyme-linked immunosorbent assay;Light microscope and electron microscope were also employed to examine whether there was some damage in ischemic area. Results:The capillary density in the ET group was statistically higher than those in the PI(P＜0.01)and SO groups(P＜0.01),the capillary density in the PI group was significantly higher than that in the SO group (P＜0.01).The relative myocardial blood flow in the ET group was higher than those in the PI(P＜0.01)and SO groups(P＜0.01),and this parameter in the PI group was also significantly higher than that in the SO group (P＜0.01).The VEGF protein expression in the ET group were statistically higher than those in the PI(P＜0.05)and SO groups(P＜0.01),The Flk-1 protein expression in the ET group were statistically higher than those in the PI(P＜0.05)and SO groups(P＜0.01);the VEGF(P＜0.05),Flk-1 (P＜0.05)protein expression increased significantly in the PI group compared to that in the SO group.The results of mRNA expression were just the same as the results of VEGF,Flk-1 protein expression.There was no myocardial damage in the ET(P＞0.05)or PI group(P＞0.05)by cardiac troponin I,light microscope and electron microscope.Conclusions:Intermittent myocardial ischemia induced by exercise with optimal stimulation safely promotes coronary collateral formation through increased VEGF and Flk-1 expression in a porcine model.更多还原