有氧训练对猪慢性冠状动脉狭窄后内皮细胞介导的侧支循环依赖血管扩张的影响

Endothelium-mediated relaxation of porcine collateral-dependent art erioles is improved by exercise training

目的 探讨有氧训练后侧支循环依赖血管的扩张与内皮介导的一氧化氮合酶 (ecNOS)的基因表达之间的关系。方法 健康雄性 3月龄猪 2 2只 ,采用Ameroid缩窄器建立慢性冠状动脉左回旋支 (LCX)狭窄模型后 ,随机分为对照组 (n =7)和运动组 (n =8)。对照组保持安静饲养 7周 ;运动组进行中等强度有氧运动训练 7周。以逆转录 聚合酶链反应 (RT PCR)法测定未狭窄冠状动脉左前降支 (LAD)和侧支循环依赖的LCX小动脉ecNOS的mRNA表达情况。结果 运动组LCX和LAD小动脉的ecNOSmRNA的表达无差异 ,P >0 .0 5 ;对照组LCX小动脉ecNOS的mRNA表达较LAD显著下降 ,P <0 .0 1。结论 运动训练可以上调狭窄的冠状动脉ecNOS的基因表达 ,增加一氧化氮 (NO)的产生 ,改善侧支循环依赖的血管的扩张 。

Objective To evaluate the hypothes is that exercise training enhances endothelium-mediated relaxation and increases endothelial constitutive nitric oxide synthase(ecNOS) mRNA levels of collateral -dependent microvasculature by use of a porcine model of chronic coronary occlu sion and collateral development. Methods Twenty-two pigs(3 months old) were subjected to chronic, progressive ameroid occlusion of the proximal left circumflex coronary artery(LCX). Four weeks after operation, t he animals were divided into the sedentary group and the exercise training group . The pigs in the exercise training group were administered with aerobic treadm ill training at moderate intensity for 7 weeks, while those in the sedentary gro up were kept sedentary. Arterioles were sampled at the end of the exercise train ing program and used for ecNOS mRNA analysis(RT-PCR techniques). Results It was found that in the sedentary animals, ecNOS mRNA exp ression in arterioles isolated from LCX was significantly decreased as compared with that in arterioles from left anterior descending coronary artery (LAD) regi ons.However, ecNOS mRNA expression was not significantly different between LAD a nd LCX arterioles in the pigs in the exercise training group. Co nclusion Exercise training enhances relaxation of collateral-depend ent LCX arterioles isolated after chronic coronary occlusion, most likely becaus e of effects on ecNOS mRNA expression and increased production of NO.