中等强度耐力运动对心脏局部Ang II及AT_1R表达的影响

Effect of Moderate-intensity Endurance Exercise on Cardiac Local Angiotensin II and Type 1 Receptor Expression

目的:探讨中等强度耐力运动对心脏局部Ang II及AT1R表达的影响及其作用机制。方法:健康雄性SD大鼠40只,随机分为耐力运动组(E组,n=20)和对照组(C组,n=20)。每组内包括2个平行的亚组:形态学检测亚组(C1/E1组,n=10)和实时荧光定量PCR检测亚组(C2/E2组,n=10)。耐力运动组进行为期8周的跑台训练,建立大鼠耐力运动型心肌肥大模型。使用实时荧光定量PCR技术,对两组大鼠心脏局部Ang II及AT1R mRNA的表达进行测定;使用免疫组织化学方法,结合计算机图像处理技术,对心脏局部Ang II及AT1R的分布和表达进行观察和测定。结果:8周中等强度耐力训练后:1)E组大鼠较C组大鼠体重发生显著性下降(P<0.05),心脏质量下降,但心系数显著增加(P<0.05),心脏组织HE染色未见病理性改变;2)E组大鼠心脏局部Ang II的mRNA表达显著增加(P<0.05),而AT1R的mRNA表达显著下调(P<0.05);3)E组大鼠心脏局部Ang II蛋白免疫反应阳性面积和光密度显著增加(P<0.05);心脏局部AT1R蛋白免疫反应阳性面积和光密度显著下调(P<0.05)。结论:1)心脏局部Ang II主要分布在心肌细胞的细胞质和细胞膜上,AT1R主要分布在冠状血管壁的平滑肌上。2)中等强度耐力运动后心脏局部Ang II表达上调,是一种对中等强度耐力运动的生理性适应性改变。3)中等强度耐力运动可使心肌细胞和冠状血管壁平滑肌上的AT1R表达下调,从而增加冠状血管血流量,避免心肌过度肥大而产生病理性改变。

Objective： To study the effect of moderate-intensity endurance exercise on cardiac local Angiotensin Ⅱ and 1 type receptor expression. Methods ： Male SD rats were randomly divided into control group （ n = 20） and moderate-intensity endurance training group （n = 20）. Using the 8-week moderate-intensity treadmill endurance training to build a cardiac hypertrophy model of rats. Using the real-time quantitative PCR method to test the mRNA expression of Ang Ⅱ and AT1R. Using the immunohistochemistry combined with computer image processing technology meas- ured the immune response positive area and optical density of Ang Ⅱ and AT1R. Result： After the cardiac hypertro- phy induced by the moderate-intensity endurance exercise, the mRNA expression of cardiac local Ang Ⅱ was signifi- cantly increased （P 〈 0.05 ）, while AT1R was significantly reduced （ P 〈 0. 05 ） ; by using immunohistochemistry combined with computer image processing technology, the Ang Ⅱ immune-positive area and optical density were sig-nificantly enhanced （ P 〈 0.05 ） ; the AT1R immune-positive area and optical density were significantly decreased （ P 〈 0.05 ）. Conclusion ： 1 ） The Ang Ⅱ mainly distributes in the cardiac muscle cell cytoplasm and the cell membrane,the AT1R mainly distributes on the coronal blood vessel smooth muscle. 2） The endurance training can make the Ang Ⅱ expression increased. 3） After the endurance training, the AT1R expression declines so as to increase coro-nal blood vessel blood current capacity and avoid changing to pathological cardiac hypertrophy.